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Merged
merged 4 commits into from
Sep 9, 2016
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@nhaustov nhaustov commented Sep 9, 2016

Code by Alexander Timofev with fixes.

@nhaustov nhaustov merged commit 1f64f88 into ROCm:amd-common Sep 9, 2016
tstellarAMD pushed a commit that referenced this pull request Nov 11, 2016
This optimization merges adjacent zero stores into a wider store.

e.g.,

strh wzr, [x0]
strh wzr, [x0, #2]
; becomes
str wzr, [x0]

e.g.,

str wzr, [x0]
str wzr, [x0, #4]
; becomes
str xzr, [x0]

Previously, this was only enabled for Kryo and Cortex-A57.

Differential Revision: https://reviews.llvm.org/D26396

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286592 91177308-0d34-0410-b5e6-96231b3b80d8
tstellarAMD pushed a commit that referenced this pull request Dec 7, 2016
BDCE has two phases:
1. It asks SimplifyDemandedBits if all the bits of an instruction are dead, and if so,
replaces all its uses with the constant zero.
2. Then, it asks SimplifyDemandedBits again if the instruction is really dead
(no side effects etc..) and if so, eliminates it.

Now, in 1) if all the bits of an instruction are dead, we may end up replacing a dbg use:
  %call = tail call i32 (...) @g() #4, !dbg !15
  tail call void @llvm.dbg.value(metadata i32 %call, i64 0, metadata !8, metadata !16), !dbg !17
->
  %call = tail call i32 (...) @g() #4, !dbg !15
  tail call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !8, metadata !16), !dbg !17

but not eliminating the call because it may have arbitrary side effects.
In other words, we lose some debug informations.
This patch fixes the problem making sure that BDCE does nothing with the instruction if
it has side effects and no non-dbg uses.

Differential Revision:  https://reviews.llvm.org/D27471

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288851 91177308-0d34-0410-b5e6-96231b3b80d8
tstellarAMD pushed a commit that referenced this pull request Feb 1, 2017
    #0 0x89cdeb in operator new[](unsigned long) /code/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:84:37
    #1 0x4ec87c4 in llvm::RegisterBankInfo::ValueMapping const* llvm::RegisterBankInfo::getOperandsMapping<llvm::RegisterBankInfo::ValueMapping const* const*>(llvm::RegisterBankInfo::ValueMapping const* const*, llvm::RegisterBankInfo::ValueMapping const* const*) const /code/llvm/lib/CodeGen/GlobalISel/RegisterBankInfo.cpp:297:9
    #2 0x9327ee in llvm::AArch64RegisterBankInfo::getInstrMapping(llvm::MachineInstr const&) const /code/llvm/lib/Target/AArch64/AArch64RegisterBankInfo.cpp:540:30
    #3 0x4eb8d07 in llvm::RegBankSelect::assignInstr(llvm::MachineInstr&) /code/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp:546:24
    #4 0x4eb9dd2 in llvm::RegBankSelect::runOnMachineFunction(llvm::MachineFunction&) /code/llvm/lib/CodeGen/GlobalISel/RegBankSelect.cpp:624:12
    #5 0x3141875 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /code/llvm/lib/CodeGen/MachineFunctionPass.cpp:62:13
    #6 0x396128d in llvm::FPPassManager::runOnFunction(llvm::Function&) /code/llvm/lib/IR/LegacyPassManager.cpp:1513:27
    #7 0x3961832 in llvm::FPPassManager::runOnModule(llvm::Module&) /code/llvm/lib/IR/LegacyPassManager.cpp:1534:16
    #8 0x3962540 in runOnModule /code/llvm/lib/IR/LegacyPassManager.cpp:1590:27
    #9 0x3962540 in llvm::legacy::PassManagerImpl::run(llvm::Module&) /code/llvm/lib/IR/LegacyPassManager.cpp:1693
    #10 0x8ae368 in compileModule(char**, llvm::LLVMContext&) /code/llvm/tools/llc/llc.cpp:562:8
    #11 0x8a7a1b in main /code/llvm/tools/llc/llc.cpp:316:22

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293351 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Oct 27, 2017
Summary:
The code comments indicate that no effort has been spent on
handling load/stores when the size isn't a multiple of the
byte size correctly. However, the code only avoided types
smaller than 8 bits. So for example a load of an i28 could
still be considered as a candidate for vectorization.

This patch adjusts the code to behave according to the code
comment.

The test case used to hit the following assert when
trying to use "cast" an i32 to i28 using CreateBitOrPointerCast:

opt: ../lib/IR/Instructions.cpp:2565: Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed.
#0 PrintStackTraceSignalHandler(void*)
#1 SignalHandler(int)
#2 __restore_rt
#3 __GI_raise
#4 __GI_abort
#5 __GI___assert_fail
#6 llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&, llvm::Instruction*)
#7 llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>::CreateBitOrPointerCast(llvm::Value*, llvm::Type*, llvm::Twine const&)
#8 (anonymous namespace)::Vectorizer::vectorizeLoadChain(llvm::ArrayRef<llvm::Instruction*>, llvm::SmallPtrSet<llvm::Instruction*, 16u>*)

Reviewers: arsenm

Reviewed By: arsenm

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39295

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316663 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Oct 27, 2017
Summary:
We no longer add vectors of pointers as candidates for
load/store vectorization. It does not seem to work anyway,
but without this patch we can end up in asserts when trying
to create casts between an integer type and the pointer of
vectors type.

The test case I've added used to assert like this when trying to
cast between i64 and <2 x i16*>:
opt: ../lib/IR/Instructions.cpp:2565: Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' failed.
#0 PrintStackTraceSignalHandler(void*)
#1 SignalHandler(int)
#2 __restore_rt
#3 __GI_raise
#4 __GI_abort
#5 __GI___assert_fail
#6 llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, llvm::Twine const&, llvm::Instruction*)
#7 llvm::IRBuilder<llvm::ConstantFolder, llvm::IRBuilderDefaultInserter>::CreateBitOrPointerCast(llvm::Value*, llvm::Type*, llvm::Twine const&)
#8 Vectorizer::vectorizeStoreChain(llvm::ArrayRef<llvm::Instruction*>, llvm::SmallPtrSet<llvm::Instruction*, 16u>*)

Reviewers: arsenm

Reviewed By: arsenm

Subscribers: nhaehnle, llvm-commits

Differential Revision: https://reviews.llvm.org/D39296

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316665 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Dec 29, 2017
Summary:
I have been getting rather difficult to reproduce SIGBUS crashes when
compiling certain FreeBSD sources, and their stack traces pointed
squarely at `SelectionDAG::salvageDebugInfo()`:

```
Core was generated by `/usr/obj/share/dim/src/freebsd/clang600-import/amd64.amd64/tmp/usr/bin/cc -cc1 -'.
Program terminated with signal SIGBUS, Bus error.
#0  isInvalidated () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h:115
115       bool isInvalidated() const { return Invalid; }
(gdb) bt
#0  isInvalidated () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SDNodeDbgValue.h:115
#1  salvageDebugInfo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7116
#2  0x00000000033b2516 in operator() () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3595
#3  __invoke<(lambda at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3593:59) &, llvm::SDNode *, llvm::SDNode *> () at /usr/include/c++/v1/type_traits:4323
#4  __call<(lambda at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3593:59) &, llvm::SDNode *, llvm::SDNode *> () at /usr/include/c++/v1/__functional_base:349
#5  operator() () at /usr/include/c++/v1/functional:1562
#6  0x00000000033b0817 in operator() () at /usr/include/c++/v1/functional:1916
#7  NodeDeleted () at /share/dim/src/freebsd/clang600-import/contrib/llvm/include/llvm/CodeGen/SelectionDAG.h:293
#8  0x0000000003529dde in RemoveDeadNodes () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:610
#9  0x00000000035556df in MorphNodeTo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:6794
#10 0x00000000033a9acc in MorphNode () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:2594
#11 0x00000000033ac80b in SelectCodeCommon () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:3601
#12 0x00000000023d464b in SelectCode () at /usr/obj/share/dim/src/freebsd/clang600-import/amd64.amd64/tmp/obj-tools/lib/clang/libllvm/X86GenDAGISel.inc:282902
#13 Select () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp:3072
#14 0x00000000033a5afa in DoInstructionSelection () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:988
#15 0x00000000033a4e1a in CodeGenAndEmitDAG () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:868
#16 0x00000000033a2643 in SelectAllBasicBlocks () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1624
#17 0x000000000339f158 in runOnMachineFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:466
#18 0x00000000023d03c4 in runOnMachineFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp:175
#19 0x00000000035cc8c2 in runOnFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/MachineFunctionPass.cpp:62
#20 0x00000000030dca9a in runOnFunction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1520
#21 0x00000000030dccf3 in runOnModule () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1541
#22 0x00000000030dd228 in runOnModule () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1597
#23 run () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/IR/LegacyPassManager.cpp:1700
#24 0x00000000014db578 in EmitAssembly () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/BackendUtil.cpp:815
#25 EmitBackendOutput () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/BackendUtil.cpp:1181
#26 0x00000000014d5b26 in HandleTranslationUnit () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/CodeGen/CodeGenAction.cpp:292
#27 0x0000000001c4c332 in ParseAST () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Parse/ParseAST.cpp:159
#28 0x00000000015d546c in Execute () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Frontend/FrontendAction.cpp:897
#29 0x0000000001cec311 in ExecuteAction () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:991
#30 0x00000000014b4f81 in ExecuteCompilerInvocation () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/lib/FrontendTool/ExecuteCompilerInvocation.cpp:252
#31 0x00000000014aa73f in cc1_main () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/cc1_main.cpp:221
#32 0x00000000014b2928 in ExecuteCC1Tool () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/driver.cpp:309
#33 main () at /share/dim/src/freebsd/clang600-import/contrib/llvm/tools/clang/tools/driver/driver.cpp:388
(gdb) frame 1
#1  salvageDebugInfo () at /share/dim/src/freebsd/clang600-import/contrib/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:7116
7116        if (DV->isInvalidated())
(gdb) disassemble
Dump of assembler code for function salvageDebugInfo():
[...]
   0x0000000003557348 <+744>:   nopl   0x0(%rax,%rax,1)
   0x0000000003557350 <+752>:   mov    (%r12),%r13
=> 0x0000000003557354 <+756>:   cmpb   $0x0,0x31(%r13)
   0x0000000003557359 <+761>:   jne    0x35573b0 <salvageDebugInfo()+848>
(gdb) info registers
[...]
r13            0x5a5a5a5a5a5a5a5a       6510615555426900570
```

The `0x5a5a5a5a5a5a5a5a` value in `r13` indicates the memory was either
uninitialized, or already freed.

Unfortunately I do not have a simple self-contained test case for this.
However, it seems pretty clear that the call to `AddDbgValue()` in
`salvageDebugInfo()` causes the problems, since it modifies
`SelectionDag::DbgInfo` while looping through one of its DenseMaps:

```
void SelectionDAG::salvageDebugInfo(SDNode &N) {
[...]
  for (auto DV : GetDbgValues(&N)) {
    if (DV->isInvalidated())
      continue;
[...]
        AddDbgValue(Clone, N0.getNode(), false);
[...]
  }
}
```

At least, if I comment out the `AddDbgValue()` call, the crashes go
away.  I propose to change this function slightly, similar to the
`SelectionDAG::transferDbgValues()` function just above it, to save the
cloned SDDbgValues in a separate SmallVector, and only call
AddDbgValue() on them after the for loop is done.

Reviewers: aprantl, bogner, bkramer, davide

Reviewed By: davide

Subscribers: davide, krytarowski, JDevlieghere, emaste, llvm-commits

Differential Revision: https://reviews.llvm.org/D41589


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321545 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Apr 21, 2018
Revert r330413: "[SSAUpdaterBulk] Use SmallVector instead of DenseMap for storing rewrites."
Revert r330403 "Reapply "[PR16756] Use SSAUpdaterBulk in JumpThreading." one more time."

r330403 commit seems to crash clang during our integrate while doing PGO build with the following stacktrace:
      #2 llvm::SSAUpdaterBulk::RewriteAllUses(llvm::DominatorTree*, llvm::SmallVectorImpl<llvm::PHINode*>*)
      #3 llvm::JumpThreadingPass::ThreadEdge(llvm::BasicBlock*, llvm::SmallVectorImpl<llvm::BasicBlock*> const&, llvm::BasicBlock*)
      #4 llvm::JumpThreadingPass::ProcessThreadableEdges(llvm::Value*, llvm::BasicBlock*, llvm::jumpthreading::ConstantPreference, llvm::Instruction*)
      #5 llvm::JumpThreadingPass::ProcessBlock(llvm::BasicBlock*)
The crash happens while compiling 'lib/Analysis/CallGraph.cpp'.

r3340413 is reverted due to conflicting changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@330416 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jun 16, 2018
Increment/decrement scalar register by (scaled) element count given by
predicate pattern, e.g. 'incw x0, all, mul #4'.

Reviewers: rengolin, fhahn, SjoerdMeijer, samparker, javed.absar

Reviewed By: SjoerdMeijer

Differential Revision: https://reviews.llvm.org/D47713



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334838 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jun 19, 2018
…tructions.

Summary:
The variants added by this patch are:
- SQINC  (signed increment)
- UQINC  (unsigned increment)
- SQDEC  (signed decrement)
- UQDEC  (unsigned decrement)

For example:
  uqincw  x0, all, mul #4

Reviewers: rengolin, fhahn, SjoerdMeijer, samparker, javed.absar

Differential Revision: https://reviews.llvm.org/D47715



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334948 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jun 19, 2018
…tructions.

The variants added by this patch are:
- SQINC     signed increment, e.g. sqinc x0, w0, all, mul #4
- SQDEC     signed decrement, e.g. sqdec x0, w0, all, mul #4
- UQINC   unsigned increment, e.g. uqinc w0, all, mul #4
- UQDEC   unsigned decrement, e.g. uqdec w0, all, mul #4
 
This patch includes asmparser changes to parse a GPR64 as a GPR32 in
order to satisfy the constraint check:
  x0 == GPR64(w0)
in:
  sqinc x0, w0, all, mul #4
         ^___^ (must match)

Reviewers: rengolin, fhahn, SjoerdMeijer, samparker, javed.absar

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D47716



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@334980 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jun 28, 2018
This patch adds a custom trunc store lowering for v4i8 vector types.
Since there is not v.4b register, the v4i8 is promoted to v4i16 (v.4h)
and default action for v4i8 is to extract each element and issue 4
byte stores.

A better strategy would be to extended the promoted v4i16 to v8i16
(with undef elements) and extract and store the word lane which
represents the v4i8 subvectores. The construction:

  define void @foo(<4 x i16> %x, i8* nocapture %p) {
    %0 = trunc <4 x i16> %x to <4 x i8>
    %1 = bitcast i8* %p to <4 x i8>*
    store <4 x i8> %0, <4 x i8>* %1, align 4, !tbaa !2
    ret void
  }

Can be optimized from:

  umov    w8, v0.h[3]
  umov    w9, v0.h[2]
  umov    w10, v0.h[1]
  umov    w11, v0.h[0]
  strb    w8, [x0, #3]
  strb    w9, [x0, #2]
  strb    w10, [x0, #1]
  strb    w11, [x0]
  ret

To:

  xtn     v0.8b, v0.8h
  str     s0, [x0]
  ret

The patch also adjust the memory cost for autovectorization, so the C
code:

  void foo (const int *src, int width, unsigned char *dst)
  {
    for (int i = 0; i < width; i++)
       *dst++ = *src++;
  }

can be vectorized to:

  .LBB0_4:                                // %vector.body
                                          // =>This Inner Loop Header: Depth=1
        ldr     q0, [x0], #16
        subs    x12, x12, #4            // =4
        xtn     v0.4h, v0.4s
        xtn     v0.8b, v0.8h
        st1     { v0.s }[0], [x2], #4
        b.ne    .LBB0_4

Instead of byte operations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335735 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 2, 2018
…ons.

Increment/decrement vector by multiple of predicate constraint
element count.

The variants added by this patch are:
 - INCH, INCW, INC 

and (saturating):
 - SQINCH, SQINCW, SQINCD
 - UQINCH, UQINCW, UQINCW
 - SQDECH, SQINCW, SQINCD
 - UQDECH, UQINCW, UQINCW

For example:
  incw z0.s, all, mul #4


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336090 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 9, 2018
r335553 with the non-trivial unswitching of switches.

The code correctly updated most aspects of the CFG and analyses, but
missed some crucial aspects:
1) When multiple cases have the same successor, we unswitch that
   a single time and replace the switch with a direct branch. The CFG
   here is correct, but the target of this direct branch may have had
   a PHI node with multiple entries in it.
2) When we still have to clone a successor of the switch into an
   unswitched copy of the loop, we'll delete potentially multiple edges
   entering this successor, not just one.
3) We also have to delete multiple edges entering the successors in the
   original loop when they have to be retained.
4) When the "retained successor" *also* occurs as a case successor, we
   just assert failed everywhere. This doesn't happen very easily
   because its always valid to simply drop the case -- the retained
   successor for switches is always the default successor. However, it
   is likely possible through some contrivance of different loop passes,
   unrolling, and simplifying for this to occur in practice and
   certainly there is nothing "invalid" about the IR so this pass needs
   to handle it.
5) In the case of #4, we also will replace these multiple edges with
   a direct branch much like in #1 and need to collapse the entries in
   any PHI nodes to a single enrty.

All of this stems from the delightful fact that the same successor can
show up in multiple parts of the switch terminator, and each of these
are considered a distinct edge for the purpose of PHI nodes (and
iterating the successors and predecessors) but not for unswitching
itself, the dominator tree, or many other things. For the record,
I intensely dislike this "feature" of the IR in large part because of
the complexity it causes in passes like this. We already have a ton of
logic building sets and handling duplicates, and we just had to add
a bunch more.

I've added a complex test case that covers all five of the above failure
modes. I've also added a variation on it where #4 and #5 occur in loop
exit, adding fun where we have an LCSSA PHI node with "multiple entries"
despite have dedicated exits. There were no additional issues found by
this, but it seems a useful corner case to cover with testing.

One thing that working on all of this code has made painfully clear for
me as well is how amazingly inefficient our PHI node representation is
(in terms of the in-memory data structures and the APIs used to update
them). This code has truly marvelous complexity bounds because every
time we remove an entry from a PHI node we do a linear scan to find it
and then a linear update to the data structure to remove it. We could in
theory batch all of the PHI node updates into a single linear walk of
the operands making this much more efficient, but the APIs fight hard
against this and the fact that we have to handle duplicates in the
peculiar manner we do (removing all but one in some cases) makes even
implementing that very tedious and annoying. Anyways, none of this is
new here or specific to loop unswitching. All code in LLVM that updates
PHI node operands suffers from these problems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336536 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 11, 2018
…d VPlan for tests."

Memory leaks in tests.
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/6289/steps/check-llvm%20asan/logs/stdio

Direct leak of 192 byte(s) in 1 object(s) allocated from:
    #0 0x554ea8 in operator new(unsigned long) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:106
    #1 0x56cef1 in llvm::VPlanTestBase::doAnalysis(llvm::Function&) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h:53:14
    #2 0x56bec4 in llvm::VPlanTestBase::buildHCFG(llvm::BasicBlock*) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanTestBase.h:57:3
    #3 0x571f1e in llvm::(anonymous namespace)::VPlanHCFGTest_testVPInstructionToVPRecipesInner_Test::TestBody() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp:119:15
    #4 0xed2291 in testing::Test::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #5 0xed44c8 in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
    #6 0xed5890 in testing::TestCase::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
    #7 0xef3634 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
    #8 0xef27e0 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #9 0xebbc23 in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
    #10 0xebbc23 in main /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/UnitTestMain/TestMain.cpp:51
    #11 0x7f65569592e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)

and more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336718 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 14, 2018
…ering"

This reverts commit r337021.

WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x1415cd65 in void write_signed<long>(llvm::raw_ostream&, long, unsigned long, llvm::IntegerStyle) /code/llvm-project/llvm/lib/Support/NativeFormatting.cpp:95:7
    #1 0x1415c900 in llvm::write_integer(llvm::raw_ostream&, long, unsigned long, llvm::IntegerStyle) /code/llvm-project/llvm/lib/Support/NativeFormatting.cpp:121:3
    #2 0x1472357f in llvm::raw_ostream::operator<<(long) /code/llvm-project/llvm/lib/Support/raw_ostream.cpp:117:3
    #3 0x13bb9d4 in llvm::raw_ostream::operator<<(int) /code/llvm-project/llvm/include/llvm/Support/raw_ostream.h:210:18
    #4 0x3c2bc18 in void printField<unsigned int, &(amd_kernel_code_s::amd_kernel_code_version_major)>(llvm::StringRef, amd_kernel_code_s const&, llvm::raw_ostream&) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:78:23
    #5 0x3c250ba in llvm::printAmdKernelCodeField(amd_kernel_code_s const&, int, llvm::raw_ostream&) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:104:5
    #6 0x3c27ca3 in llvm::dumpAmdKernelCode(amd_kernel_code_s const*, llvm::raw_ostream&, char const*) /code/llvm-project/llvm/lib/Target/AMDGPU/Utils/AMDKernelCodeTUtils.cpp:113:5
    #7 0x3a46e6c in llvm::AMDGPUTargetAsmStreamer::EmitAMDKernelCodeT(amd_kernel_code_s const&) /code/llvm-project/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUTargetStreamer.cpp:161:3
    #8 0xd371e4 in llvm::AMDGPUAsmPrinter::EmitFunctionBodyStart() /code/llvm-project/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp:204:26

[...]

Uninitialized value was created by an allocation of 'KernelCode' in the stack frame of function '_ZN4llvm16AMDGPUAsmPrinter21EmitFunctionBodyStartEv'
    #0 0xd36650 in llvm::AMDGPUAsmPrinter::EmitFunctionBodyStart() /code/llvm-project/llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp:192

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337079 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Aug 9, 2018
Summary:
Currently, in line with GCC, when specifying reserved registers like sp or pc on an inline asm() clobber list, we don't always preserve the original value across the statement. And in general, overwriting reserved registers can have surprising results.

For example:


```
extern int bar(int[]);

int foo(int i) {
  int a[i]; // VLA
  asm volatile(
      "mov r7, #1"
    :
    :
    : "r7"
  );

  return 1 + bar(a);
}
```

Compiled for thumb, this gives:
```
$ clang --target=arm-arm-none-eabi -march=armv7a -c test.c -o - -S -O1 -mthumb
...
foo:
        .fnstart
@ %bb.0:                                @ %entry
        .save   {r4, r5, r6, r7, lr}
        push    {r4, r5, r6, r7, lr}
        .setfp  r7, sp, #12
        add     r7, sp, #12
        .pad    #4
        sub     sp, #4
        movs    r1, #7
        add.w   r0, r1, r0, lsl #2
        bic     r0, r0, #7
        sub.w   r0, sp, r0
        mov     sp, r0
        @app
        mov.w   r7, #1
        @NO_APP
        bl      bar
        adds    r0, #1
        sub.w   r4, r7, #12
        mov     sp, r4
        pop     {r4, r5, r6, r7, pc}
...
```

r7 is used as the frame pointer for thumb targets, and this function needs to restore the SP from the FP because of the variable-length stack allocation a. r7 is clobbered by the inline assembly (and r7 is included in the clobber list), but LLVM does not preserve the value of the frame pointer across the assembly block.

This type of behavior is similar to GCC's and has been discussed on the bugtracker: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=11807 . No consensus seemed to have been reached on the way forward.  Clang behavior has briefly been discussed on the CFE mailing (starting here: http://lists.llvm.org/pipermail/cfe-dev/2018-July/058392.html). I've opted for following Eli Friedman's advice to print warnings when there are reserved registers on the clobber list so as not to diverge from GCC behavior for now.

The patch uses MachineRegisterInfo's target-specific knowledge of reserved registers, just before we convert the inline asm string in the AsmPrinter.

If we find a reserved register, we print a warning:
```
repro.c:6:7: warning: inline asm clobber list contains reserved registers: R7 [-Winline-asm]
      "mov r7, #1"
      ^
```

Reviewers: eli.friedman, olista01, javed.absar, efriedma

Reviewed By: efriedma

Subscribers: efriedma, eraman, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D49727

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@339257 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Aug 30, 2018
Summary:
This is a continuation of https://reviews.llvm.org/D49727
Below the original text, current changes in the comments:

Currently, in line with GCC, when specifying reserved registers like sp or pc on an inline asm() clobber list, we don't always preserve the original value across the statement. And in general, overwriting reserved registers can have surprising results.

For example:

  extern int bar(int[]);
  
  int foo(int i) {
    int a[i]; // VLA
    asm volatile(
        "mov r7, #1"
      :
      :
      : "r7"
    );
  
    return 1 + bar(a);
  }

Compiled for thumb, this gives:

  $ clang --target=arm-arm-none-eabi -march=armv7a -c test.c -o - -S -O1 -mthumb
  ...
  foo:
          .fnstart
  @ %bb.0:                                @ %entry
          .save   {r4, r5, r6, r7, lr}
          push    {r4, r5, r6, r7, lr}
          .setfp  r7, sp, #12
          add     r7, sp, #12
          .pad    #4
          sub     sp, #4
          movs    r1, #7
          add.w   r0, r1, r0, lsl #2
          bic     r0, r0, #7
          sub.w   r0, sp, r0
          mov     sp, r0
          @app
          mov.w   r7, #1
          @NO_APP
          bl      bar
          adds    r0, #1
          sub.w   r4, r7, #12
          mov     sp, r4
          pop     {r4, r5, r6, r7, pc}
  ...

r7 is used as the frame pointer for thumb targets, and this function needs to restore the SP from the FP because of the variable-length stack allocation a. r7 is clobbered by the inline assembly (and r7 is included in the clobber list), but LLVM does not preserve the value of the frame pointer across the assembly block.

This type of behavior is similar to GCC's and has been discussed on the bugtracker: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=11807 . No consensus seemed to have been reached on the way forward. Clang behavior has briefly been discussed on the CFE mailing (starting here: http://lists.llvm.org/pipermail/cfe-dev/2018-July/058392.html). I've opted for following Eli Friedman's advice to print warnings when there are reserved registers on the clobber list so as not to diverge from GCC behavior for now.

The patch uses MachineRegisterInfo's target-specific knowledge of reserved registers, just before we convert the inline asm string in the AsmPrinter.

If we find a reserved register, we print a warning:

  repro.c:6:7: warning: inline asm clobber list contains reserved registers: R7 [-Winline-asm]
        "mov r7, #1"
        ^

Reviewers: efriedma, olista01, javed.absar

Reviewed By: efriedma

Subscribers: eraman, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D51165

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@341062 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Oct 26, 2018
…>> (32 - y) pattern"

*Seems* to be breaking sanitizer-x86_64-linux-fast buildbot,
the ELF/relocatable-versioned.s test:

==17758==MemorySanitizer CHECK failed: /b/sanitizer-x86_64-linux-fast/build/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc:191 "((kBlockMagic)) == ((((u64*)addr)[0]))" (0x6a6cb03abcebc041, 0x0)
    #0 0x59716b in MsanCheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /b/sanitizer-x86_64-linux-fast/build/llvm/projects/compiler-rt/lib/msan/msan.cc:393
    #1 0x586635 in __sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) /b/sanitizer-x86_64-linux-fast/build/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_termination.cc:79
    #2 0x57d5ff in __sanitizer::InternalFree(void*, __sanitizer::SizeClassAllocatorLocalCache<__sanitizer::SizeClassAllocator32<__sanitizer::AP32> >*) /b/sanitizer-x86_64-linux-fast/build/llvm/projects/compiler-rt/lib/sanitizer_common/sanitizer_allocator.cc:191
    #3 0x7fc21b24193f  (/lib/x86_64-linux-gnu/libc.so.6+0x3593f)
    #4 0x7fc21b241999 in exit (/lib/x86_64-linux-gnu/libc.so.6+0x35999)
    #5 0x7fc21b22c2e7 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e7)
    #6 0x57c039 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/lld+0x57c039)

This reverts commit r345014.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345017 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Nov 15, 2018
Flags variable was not initialized and later used (both isMBBSafeToOutlineFrom
implementations assume it's initialized), which breaks
test/CodeGen/AArch64/machine-outliner.mir. under memory sanitizer:
MemorySanitizer: use-of-uninitialized-value
    #0  in llvm::AArch64InstrInfo::getOutliningType(llvm::MachineInstrBundleIterator<llvm::MachineInstr, false>&, unsigned int) const llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:5494:9
    #1  in (anonymous namespace)::InstructionMapper::convertToUnsignedVec(llvm::MachineBasicBlock&, llvm::TargetInstrInfo const&) llvm/lib/CodeGen/MachineOutliner.cpp:772:19
    #2  in (anonymous namespace)::MachineOutliner::populateMapper((anonymous namespace)::InstructionMapper&, llvm::Module&, llvm::MachineModuleInfo&) llvm/lib/CodeGen/MachineOutliner.cpp:1543:14
    #3  in (anonymous namespace)::MachineOutliner::runOnModule(llvm::Module&) llvm/lib/CodeGen/MachineOutliner.cpp:1645:3
    #4  in (anonymous namespace)::MPPassManager::runOnModule(llvm::Module&) llvm/lib/IR/LegacyPassManager.cpp:1744:27
    #5  in llvm::legacy::PassManagerImpl::run(llvm::Module&) llvm/lib/IR/LegacyPassManager.cpp:1857:44
    #6  in compileModule(char**, llvm::LLVMContext&) llvm/tools/llc/llc.cpp:597:8

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346761 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jan 19, 2019
Summary:
Scanning blocks in sub-loops for uses is unnecessary, as they were
already handled while dealing with the containing sub-loop.

This speeds up LCSSA for highly nested loops. For the test case in PR37202, it
halves the time spent in LCSSA. In cases were we won't be able to skip
any blocks, the additional lookup should be negligible.

Time-passes without this patch for test case from PR37202:

  Total Execution Time: 48.5505 seconds (48.5511 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
  10.0822 ( 21.0%)   0.1406 ( 27.0%)  10.2228 ( 21.1%)  10.2228 ( 21.1%)  Loop-Closed SSA Form Pass
  10.0417 ( 20.9%)   0.1467 ( 28.2%)  10.1884 ( 21.0%)  10.1890 ( 21.0%)  Loop-Closed SSA Form Pass #2
   4.2703 (  8.9%)   0.0040 (  0.8%)   4.2742 (  8.8%)   4.2742 (  8.8%)  Unswitch loops
   2.7376 (  5.7%)   0.0229 (  4.4%)   2.7605 (  5.7%)   2.7611 (  5.7%)  Loop-Closed SSA Form Pass #5
   2.7332 (  5.7%)   0.0214 (  4.1%)   2.7546 (  5.7%)   2.7546 (  5.7%)  Loop-Closed SSA Form Pass #3
   2.7088 (  5.6%)   0.0230 (  4.4%)   2.7319 (  5.6%)   2.7324 (  5.6%)  Loop-Closed SSA Form Pass #4
   2.6855 (  5.6%)   0.0236 (  4.5%)   2.7091 (  5.6%)   2.7090 (  5.6%)  Loop-Closed SSA Form Pass #6
   2.1648 (  4.5%)   0.0018 (  0.4%)   2.1666 (  4.5%)   2.1664 (  4.5%)  Unroll loops
   1.8371 (  3.8%)   0.0009 (  0.2%)   1.8379 (  3.8%)   1.8380 (  3.8%)  Value Propagation
   1.8149 (  3.8%)   0.0021 (  0.4%)   1.8170 (  3.7%)   1.8169 (  3.7%)  Loop Invariant Code Motion
   1.6755 (  3.5%)   0.0226 (  4.3%)   1.6981 (  3.5%)   1.6980 (  3.5%)  Loop-Closed SSA Form Pass #7

Time-passes with this patch

  Total Execution Time: 29.9285 seconds (29.9276 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   5.2786 ( 17.7%)   0.0021 (  1.2%)   5.2806 ( 17.6%)   5.2808 ( 17.6%)  Unswitch loops
   4.3739 ( 14.7%)   0.0303 ( 18.1%)   4.4042 ( 14.7%)   4.4042 ( 14.7%)  Loop-Closed SSA Form Pass
   4.2658 ( 14.3%)   0.0192 ( 11.5%)   4.2850 ( 14.3%)   4.2851 ( 14.3%)  Loop-Closed SSA Form Pass #2
   2.2307 (  7.5%)   0.0013 (  0.8%)   2.2320 (  7.5%)   2.2318 (  7.5%)  Loop Invariant Code Motion
   2.0888 (  7.0%)   0.0012 (  0.7%)   2.0900 (  7.0%)   2.0897 (  7.0%)  Unroll loops
   1.6761 (  5.6%)   0.0013 (  0.8%)   1.6774 (  5.6%)   1.6774 (  5.6%)  Value Propagation
   1.3686 (  4.6%)   0.0029 (  1.8%)   1.3716 (  4.6%)   1.3714 (  4.6%)  Induction Variable Simplification
   1.1457 (  3.8%)   0.0010 (  0.6%)   1.1468 (  3.8%)   1.1468 (  3.8%)  Loop-Closed SSA Form Pass #4
   1.1384 (  3.8%)   0.0005 (  0.3%)   1.1389 (  3.8%)   1.1389 (  3.8%)  Loop-Closed SSA Form Pass #6
   1.1360 (  3.8%)   0.0027 (  1.6%)   1.1387 (  3.8%)   1.1387 (  3.8%)  Loop-Closed SSA Form Pass #5
   1.1331 (  3.8%)   0.0010 (  0.6%)   1.1341 (  3.8%)   1.1340 (  3.8%)  Loop-Closed SSA Form Pass #3

Reviewers: davide, efriedma, mzolotukhin

Reviewed By: davide, efriedma

Subscribers: hiraditya, dmgreen, llvm-commits

Differential Revision: https://reviews.llvm.org/D56848

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@351567 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Feb 2, 2019
If there is only a single available value, all uses must be dominated by
the single value and there is no need to search for a reaching
definition.

This drastically speeds up LCSSA in some cases. For the test case
from PR37202, it speeds up LCSSA construction by 4 times.

Time-passes without this patch for test case from PR37202:

    Total Execution Time: 29.9285 seconds (29.9276 wall clock)

    ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
    5.2786 ( 17.7%)   0.0021 (  1.2%)   5.2806 ( 17.6%)   5.2808 ( 17.6%)  Unswitch loops
    4.3739 ( 14.7%)   0.0303 ( 18.1%)   4.4042 ( 14.7%)   4.4042 ( 14.7%)  Loop-Closed SSA Form Pass
    4.2658 ( 14.3%)   0.0192 ( 11.5%)   4.2850 ( 14.3%)   4.2851 ( 14.3%)  Loop-Closed SSA Form Pass #2
    2.2307 (  7.5%)   0.0013 (  0.8%)   2.2320 (  7.5%)   2.2318 (  7.5%)  Loop Invariant Code Motion
    2.0888 (  7.0%)   0.0012 (  0.7%)   2.0900 (  7.0%)   2.0897 (  7.0%)  Unroll loops
    1.6761 (  5.6%)   0.0013 (  0.8%)   1.6774 (  5.6%)   1.6774 (  5.6%)  Value Propagation
    1.3686 (  4.6%)   0.0029 (  1.8%)   1.3716 (  4.6%)   1.3714 (  4.6%)  Induction Variable Simplification
    1.1457 (  3.8%)   0.0010 (  0.6%)   1.1468 (  3.8%)   1.1468 (  3.8%)  Loop-Closed SSA Form Pass #4
    1.1384 (  3.8%)   0.0005 (  0.3%)   1.1389 (  3.8%)   1.1389 (  3.8%)  Loop-Closed SSA Form Pass #6
    1.1360 (  3.8%)   0.0027 (  1.6%)   1.1387 (  3.8%)   1.1387 (  3.8%)  Loop-Closed SSA Form Pass #5
    1.1331 (  3.8%)   0.0010 (  0.6%)   1.1341 (  3.8%)   1.1340 (  3.8%)  Loop-Closed SSA Form Pass #3

Time passes with this patch

  Total Execution Time: 19.2802 seconds (19.2813 wall clock)

   ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Name ---
   4.4234 ( 23.2%)   0.0038 (  2.0%)   4.4272 ( 23.0%)   4.4273 ( 23.0%)  Unswitch loops
   2.3828 ( 12.5%)   0.0020 (  1.1%)   2.3848 ( 12.4%)   2.3847 ( 12.4%)  Unroll loops
   1.8714 (  9.8%)   0.0020 (  1.1%)   1.8734 (  9.7%)   1.8735 (  9.7%)  Loop Invariant Code Motion
   1.7973 (  9.4%)   0.0022 (  1.2%)   1.7995 (  9.3%)   1.8003 (  9.3%)  Value Propagation
   1.4010 (  7.3%)   0.0033 (  1.8%)   1.4043 (  7.3%)   1.4044 (  7.3%)  Induction Variable Simplification
   0.9978 (  5.2%)   0.0244 ( 13.1%)   1.0222 (  5.3%)   1.0224 (  5.3%)  Loop-Closed SSA Form Pass #2
   0.9611 (  5.0%)   0.0257 ( 13.8%)   0.9868 (  5.1%)   0.9868 (  5.1%)  Loop-Closed SSA Form Pass
   0.5856 (  3.1%)   0.0015 (  0.8%)   0.5871 (  3.0%)   0.5869 (  3.0%)  Unroll loops #2
   0.4132 (  2.2%)   0.0012 (  0.7%)   0.4145 (  2.1%)   0.4143 (  2.1%)  Loop Invariant Code Motion #3

Reviewers: efriedma, davide, mzolotukhin

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D57033

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352960 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Feb 27, 2019
Currently, the LLVM will print an error like
  Unsupported relocation: try to compile with -O2 or above,
  or check your static variable usage
if user defines more than one static variables in a single
ELF section (e.g., .bss or .data).

There is ongoing effort to support static and global
variables in libbpf and kernel. This patch removed the
assertion so user programs with static variables won't
fail compilation.

The static variable in-section offset is written to
the "imm" field of the corresponding to-be-relocated
bpf instruction. Below is an example to show how the
application (e.g., libbpf) can relate variable to relocations.

  -bash-4.4$ cat g1.c
  static volatile long a = 2;
  static volatile int b = 3;
  int test() { return a + b; }
  -bash-4.4$ clang -target bpf -O2 -c g1.c
  -bash-4.4$ llvm-readelf -r g1.o

  Relocation section '.rel.text' at offset 0x158 contains 2 entries:
      Offset             Info             Type               Symbol's Value  Symbol's Name
  0000000000000000  0000000400000001 R_BPF_64_64            0000000000000000 .data
  0000000000000018  0000000400000001 R_BPF_64_64            0000000000000000 .data
  -bash-4.4$ llvm-readelf -s g1.o

  Symbol table '.symtab' contains 6 entries:
     Num:    Value          Size Type    Bind   Vis      Ndx Name
       0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
       1: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS g1.c
       2: 0000000000000000     8 OBJECT  LOCAL  DEFAULT    4 a
       3: 0000000000000008     4 OBJECT  LOCAL  DEFAULT    4 b
       4: 0000000000000000     0 SECTION LOCAL  DEFAULT    4
       5: 0000000000000000    64 FUNC    GLOBAL DEFAULT    2 test
  -bash-4.4$ llvm-objdump -d g1.o

  g1.o:   file format ELF64-BPF

  Disassembly of section .text:
  0000000000000000 test:
       0:       18 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00         r1 = 0 ll
       2:       79 11 00 00 00 00 00 00         r1 = *(u64 *)(r1 + 0)
       3:       18 02 00 00 08 00 00 00 00 00 00 00 00 00 00 00         r2 = 8 ll
       5:       61 20 00 00 00 00 00 00         r0 = *(u32 *)(r2 + 0)
       6:       0f 10 00 00 00 00 00 00         r0 += r1
       7:       95 00 00 00 00 00 00 00         exit
  -bash-4.4$

  . from symbol table, static variable "a" is in section #4, offset 0.
  . from symbol table, static variable "b" is in section #4, offset 8.
  . the first relocation is against symbol #4:
    4: 0000000000000000     0 SECTION LOCAL  DEFAULT    4
    and in-section offset 0 (see llvm-objdump result)
  . the second relocation is against symbol #4:
    4: 0000000000000000     0 SECTION LOCAL  DEFAULT    4
    and in-section offset 8 (see llvm-objdump result)
  . therefore, the first relocation is for variable "a", and
    the second relocation is for variable "b".

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Yonghong Song <yhs@fb.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@354954 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Mar 7, 2019
Introduces memory leak in FunctionTest.GetPointerAlignment that breaks sanitizer buildbots:

```
=================================================================
==2453==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 128 byte(s) in 1 object(s) allocated from:
    #0 0x610428 in operator new(unsigned long) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:105
    #1 0x16936bc in llvm::User::operator new(unsigned long) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/User.cpp:151:19
    #2 0x7c3fe9 in Create /b/sanitizer-x86_64-linux-bootstrap/build/llvm/include/llvm/IR/Function.h:144:12
    #3 0x7c3fe9 in (anonymous namespace)::FunctionTest_GetPointerAlignment_Test::TestBody() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/IR/FunctionTest.cpp:136
    #4 0x1a836a0 in HandleExceptionsInMethodIfSupported<testing::Test, void> /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #5 0x1a836a0 in testing::Test::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2474
    #6 0x1a85c55 in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
    #7 0x1a870d0 in testing::TestCase::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
    #8 0x1aa5b84 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
    #9 0x1aa4d30 in HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool> /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #10 0x1aa4d30 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4257
    #11 0x1a6b656 in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
    #12 0x1a6b656 in main /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/UnitTestMain/TestMain.cpp:50
    #13 0x7f5af37a22e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)

Indirect leak of 40 byte(s) in 1 object(s) allocated from:
    #0 0x610428 in operator new(unsigned long) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/projects/compiler-rt/lib/asan/asan_new_delete.cc:105
    #1 0x151be6b in make_unique<llvm::ValueSymbolTable> /b/sanitizer-x86_64-linux-bootstrap/build/llvm/include/llvm/ADT/STLExtras.h:1349:29
    #2 0x151be6b in llvm::Function::Function(llvm::FunctionType*, llvm::GlobalValue::LinkageTypes, unsigned int, llvm::Twine const&, llvm::Module*) /b/sanitizer-x86_64-linux-bootstrap/build/llvm/lib/IR/Function.cpp:241
    #3 0x7c4006 in Create /b/sanitizer-x86_64-linux-bootstrap/build/llvm/include/llvm/IR/Function.h:144:16
    #4 0x7c4006 in (anonymous namespace)::FunctionTest_GetPointerAlignment_Test::TestBody() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/unittests/IR/FunctionTest.cpp:136
    #5 0x1a836a0 in HandleExceptionsInMethodIfSupported<testing::Test, void> /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #6 0x1a836a0 in testing::Test::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2474
    #7 0x1a85c55 in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
    #8 0x1a870d0 in testing::TestCase::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
    #9 0x1aa5b84 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
    #10 0x1aa4d30 in HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool> /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc
    #11 0x1aa4d30 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/src/gtest.cc:4257
    #12 0x1a6b656 in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
    #13 0x1a6b656 in main /b/sanitizer-x86_64-linux-bootstrap/build/llvm/utils/unittest/UnitTestMain/TestMain.cpp:50
    #14 0x7f5af37a22e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)

SUMMARY: AddressSanitizer: 168 byte(s) leaked in 2 allocation(s).
```

See http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/11358/steps/check-llvm%20asan/logs/stdio for more information.

Also introduces use-of-uninitialized-value in ConstantsTest.FoldGlobalVariablePtr:
```
==7070==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x14e703c in User /b/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/IR/User.h:79:5
    #1 0x14e703c in Constant /b/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/IR/Constant.h:44
    #2 0x14e703c in llvm::GlobalValue::GlobalValue(llvm::Type*, llvm::Value::ValueTy, llvm::Use*, unsigned int, llvm::GlobalValue::LinkageTypes, llvm::Twine const&, unsigned int) /b/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/IR/GlobalValue.h:78
    #3 0x14e5467 in GlobalObject /b/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/IR/GlobalObject.h:34:9
    #4 0x14e5467 in llvm::GlobalVariable::GlobalVariable(llvm::Type*, bool, llvm::GlobalValue::LinkageTypes, llvm::Constant*, llvm::Twine const&, llvm::GlobalValue::ThreadLocalMode, unsigned int, bool) /b/sanitizer-x86_64-linux-fast/build/llvm/lib/IR/Globals.cpp:314
    #5 0x6938f1 in llvm::(anonymous namespace)::ConstantsTest_FoldGlobalVariablePtr_Test::TestBody() /b/sanitizer-x86_64-linux-fast/build/llvm/unittests/IR/ConstantsTest.cpp:565:18
    #6 0x1a240a1 in HandleExceptionsInMethodIfSupported<testing::Test, void> /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc
    #7 0x1a240a1 in testing::Test::Run() /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc:2474
    #8 0x1a26d26 in testing::TestInfo::Run() /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc:2656:11
    #9 0x1a2815f in testing::TestCase::Run() /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc:2774:28
    #10 0x1a43de8 in testing::internal::UnitTestImpl::RunAllTests() /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc:4649:43
    #11 0x1a42c47 in HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool> /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc
    #12 0x1a42c47 in testing::UnitTest::Run() /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/src/gtest.cc:4257
    #13 0x1a0dfba in RUN_ALL_TESTS /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/googletest/include/gtest/gtest.h:2233:46
    #14 0x1a0dfba in main /b/sanitizer-x86_64-linux-fast/build/llvm/utils/unittest/UnitTestMain/TestMain.cpp:50
    #15 0x7f2081c412e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
    #16 0x4dff49 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/unittests/IR/IRTests+0x4dff49)

SUMMARY: MemorySanitizer: use-of-uninitialized-value /b/sanitizer-x86_64-linux-fast/build/llvm/include/llvm/IR/User.h:79:5 in User
```

See http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/30222/steps/check-llvm%20msan/logs/stdio for more information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355616 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jun 12, 2019
Looks like a MachinePipeliner algorithm problem found by
sanitizer-x86_64-linux-fast.
I will backout this test first while investigating the problem to
unblock buildbot.

==49637==ERROR: AddressSanitizer: heap-buffer-overflow on address
0x614000002e08 at pc 0x000004364350 bp 0x7ffe228a3bd0 sp 0x7ffe228a3bc8
READ of size 4 at 0x614000002e08 thread T0
    #0 0x436434f in
llvm::SwingSchedulerDAG::checkValidNodeOrder(llvm::SmallVector<llvm::NodeSet,
8u> const&) const
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/CodeGen/MachinePipeliner.cpp:3736:11
    #1 0x4342cd0 in llvm::SwingSchedulerDAG::schedule()
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/CodeGen/MachinePipeliner.cpp:486:3
    #2 0x434042d in
llvm::MachinePipeliner::swingModuloScheduler(llvm::MachineLoop&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/CodeGen/MachinePipeliner.cpp:385:7
    #3 0x433eb90 in
llvm::MachinePipeliner::runOnMachineFunction(llvm::MachineFunction&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/CodeGen/MachinePipeliner.cpp:207:5
    #4 0x428b7ea in
llvm::MachineFunctionPass::runOnFunction(llvm::Function&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/CodeGen/MachineFunctionPass.cpp:73:13
    #5 0x4d1a913 in llvm::FPPassManager::runOnFunction(llvm::Function&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/IR/LegacyPassManager.cpp:1648:27
    #6 0x4d1b192 in llvm::FPPassManager::runOnModule(llvm::Module&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/IR/LegacyPassManager.cpp:1685:16
    #7 0x4d1c06d in runOnModule
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/IR/LegacyPassManager.cpp:1752:27
    #8 0x4d1c06d in llvm::legacy::PassManagerImpl::run(llvm::Module&)
/b/sanitizer-x86_64-linux-fast/build/llvm/lib/IR/LegacyPassManager.cpp:1865
    #9 0xa48ca3 in compileModule(char**, llvm::LLVMContext&)
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/llc/llc.cpp:611:8
    #10 0xa4270f in main
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/llc/llc.cpp:365:22
    #11 0x7fec902572e0 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
    #12 0x971b69 in _start
(/b/sanitizer-x86_64-linux-fast/build/llvm_build_asan/bin/llc+0x971b69)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@363105 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 8, 2019
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:

  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61810

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365352 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Jul 9, 2019
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:

  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

The test case ThinLTO/X86/lazyload_metadata.ll is adjusted to reflect the
new addition of the metadata.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61810

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365423 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Sep 2, 2019
…ymbol that belongs to a section with a broken sh_name"

It broke BB:
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/16955/steps/test/logs/stdio

Expected<T> must be checked before access or destruction.
Unchecked Expected<T> contained error:
a section [index 1] has an invalid sh_name (0xffff) offset which goes past the end of the section name string tableStack dump:
0.	Program arguments: /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/test/tools/llvm-nm/Output/format-sysv-section.test.tmp2.o --format=sysv 
 #0 0x00000000008af7c4 PrintStackTraceSignalHandler(void*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8af7c4)
 #1 0x00000000008ad8be llvm::sys::RunSignalHandlers() (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8ad8be)
 #2 0x00000000008afbd8 SignalHandler(int) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8afbd8)
 #3 0x00007f0a6b989730 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12730)
 #4 0x00007f0a6b48d7bb raise (/lib/x86_64-linux-gnu/libc.so.6+0x377bb)
 #5 0x00007f0a6b478535 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22535)
 #6 0x000000000042004b llvm::Expected<llvm::StringRef>::fatalUncheckedExpected() const (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x42004b)
 #7 0x00000000008367f5 (/sv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8367f5)
 #8 0x0000000000817b80 llvm::object::IRObjectFile::findBitcodeInObject(llvm::object::ObjectFile const&) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x817b80)
 #9 0x0000000000838416 llvm::object::SymbolicFile::createSymbolicFile(llvm::MemoryBufferRef, llvm::file_magic, llvm::LLVMContext*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x838416)
#10 0x00000000007f36cb llvm::object::createBinary(llvm::MemoryBufferRef, llvm::LLVMContext*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x7f36cb)
#11 0x0000000000413123 dumpSymbolNamesFromFile(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x413123)
#12 0x0000000000412e38 main (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x412e38)
#13 0x00007f0a6b47a09b __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409b)
#14 0x00000000004120da _start (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x4120da)
FileCheck error: '-' is empty.
FileCheck command line:  /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/FileCheck /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.src/test/tools/llvm-nm/format-sysv-section.test --check-prefix=ERR

--

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370662 91177308-0d34-0410-b5e6-96231b3b80d8
kzhuravl pushed a commit that referenced this pull request Sep 19, 2019
Summary:
This reverts commit r372204.

This change causes build bot failures under msan:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/35236/steps/check-llvm%20msan/logs/stdio:

```
FAIL: LLVM :: DebugInfo/AArch64/asan-stack-vars.mir (19531 of 33579)
******************** TEST 'LLVM :: DebugInfo/AArch64/asan-stack-vars.mir' FAILED ********************
Script:
--
: 'RUN: at line 1';   /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llc -O0 -start-before=livedebugvalues -filetype=obj -o - /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir | /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llvm-dwarfdump -v - | /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
--
Exit Code: 2

Command Output (stderr):
--
==62894==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0xdfcafb in llvm::AArch64FrameLowering::resolveFrameOffsetReference(llvm::MachineFunction const&, int, bool, unsigned int&, bool, bool) const /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1658:3
    #1 0xdfae8a in resolveFrameIndexReference /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1580:10
    #2 0xdfae8a in llvm::AArch64FrameLowering::getFrameIndexReference(llvm::MachineFunction const&, int, unsigned int&) const /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1536
    #3 0x46642c1 in (anonymous namespace)::LiveDebugValues::extractSpillBaseRegAndOffset(llvm::MachineInstr const&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:582:21
    #4 0x4647cb3 in transferSpillOrRestoreInst /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:883:11
    #5 0x4647cb3 in process /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1079
    #6 0x4647cb3 in (anonymous namespace)::LiveDebugValues::ExtendRanges(llvm::MachineFunction&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1361
    #7 0x463ac0e in (anonymous namespace)::LiveDebugValues::runOnMachineFunction(llvm::MachineFunction&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/LiveDebugValues.cpp:1415:18
    #8 0x4854ef0 in llvm::MachineFunctionPass::runOnFunction(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/CodeGen/MachineFunctionPass.cpp:73:13
    #9 0x53b0b01 in llvm::FPPassManager::runOnFunction(llvm::Function&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1648:27
    #10 0x53b15f6 in llvm::FPPassManager::runOnModule(llvm::Module&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1685:16
    #11 0x53b298d in runOnModule /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1750:27
    #12 0x53b298d in llvm::legacy::PassManagerImpl::run(llvm::Module&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/IR/LegacyPassManager.cpp:1863
    #13 0x905f21 in compileModule(char**, llvm::LLVMContext&) /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/llc/llc.cpp:601:8
    #14 0x8fdc4e in main /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/tools/llc/llc.cpp:355:22
    #15 0x7f67673632e0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202e0)
    #16 0x882369 in _start (/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/llc+0x882369)

MemorySanitizer: use-of-uninitialized-value /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/lib/Target/AArch64/AArch64FrameLowering.cpp:1658:3 in llvm::AArch64FrameLowering::resolveFrameOffsetReference(llvm::MachineFunction const&, int, bool, unsigned int&, bool, bool) const
Exiting
error: -: The file was not recognized as a valid object file
FileCheck error: '-' is empty.
FileCheck command line:  /b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/FileCheck /b/sanitizer-x86_64-linux-fast/build/llvm-project/llvm/test/DebugInfo/AArch64/asan-stack-vars.mir
```

Reviewers: bkramer

Reviewed By: bkramer

Subscribers: sdardis, aprantl, kristof.beyls, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67710

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372228 91177308-0d34-0410-b5e6-96231b3b80d8
JaxLinAMD pushed a commit to GPUOpen-Drivers/llvm that referenced this pull request Sep 25, 2019
…ymbol that belongs to a section with a broken sh_name"

It broke BB:
http://lab.llvm.org:8011/builders/clang-x86_64-debian-fast/builds/16955/steps/test/logs/stdio

Expected<T> must be checked before access or destruction.
Unchecked Expected<T> contained error:
a section [index 1] has an invalid sh_name (0xffff) offset which goes past the end of the section name string tableStack dump:
0.	Program arguments: /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/test/tools/llvm-nm/Output/format-sysv-section.test.tmp2.o --format=sysv 
 #0 0x00000000008af7c4 PrintStackTraceSignalHandler(void*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8af7c4)
 #1 0x00000000008ad8be llvm::sys::RunSignalHandlers() (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8ad8be)
 #2 0x00000000008afbd8 SignalHandler(int) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8afbd8)
 ROCm#3 0x00007f0a6b989730 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12730)
 ROCm#4 0x00007f0a6b48d7bb raise (/lib/x86_64-linux-gnu/libc.so.6+0x377bb)
 ROCm#5 0x00007f0a6b478535 abort (/lib/x86_64-linux-gnu/libc.so.6+0x22535)
 ROCm#6 0x000000000042004b llvm::Expected<llvm::StringRef>::fatalUncheckedExpected() const (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x42004b)
 ROCm#7 0x00000000008367f5 (/sv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x8367f5)
 ROCm#8 0x0000000000817b80 llvm::object::IRObjectFile::findBitcodeInObject(llvm::object::ObjectFile const&) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x817b80)
 ROCm#9 0x0000000000838416 llvm::object::SymbolicFile::createSymbolicFile(llvm::MemoryBufferRef, llvm::file_magic, llvm::LLVMContext*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x838416)
ROCm#10 0x00000000007f36cb llvm::object::createBinary(llvm::MemoryBufferRef, llvm::LLVMContext*) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x7f36cb)
ROCm#11 0x0000000000413123 dumpSymbolNamesFromFile(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x413123)
ROCm#12 0x0000000000412e38 main (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x412e38)
ROCm#13 0x00007f0a6b47a09b __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2409b)
ROCm#14 0x00000000004120da _start (/srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/llvm-nm+0x4120da)
FileCheck error: '-' is empty.
FileCheck command line:  /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.obj/bin/FileCheck /srv/llvm-buildbot-srcatch/llvm-build-dir/clang-x86_64-debian-fast/llvm.src/test/tools/llvm-nm/format-sysv-section.test --check-prefix=ERR

--

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@370662 91177308-0d34-0410-b5e6-96231b3b80d8
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