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Changes for LLDB upstream merge #31

Merged
merged 23 commits into from
Nov 3, 2016
Merged

Changes for LLDB upstream merge #31

merged 23 commits into from
Nov 3, 2016

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tfiala
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@tfiala tfiala commented Nov 1, 2016

The LLDB team is doing a merge from swift-lldb/master-next into swift-lldb/master to go along with the llvm and clang swift-3.1-branch branch. This PR is a small collection of changes where code was either refactored out of LLDB into LLVM, or was added to support LLDB use cases, and are easier to bring in than to temporarily mask out of the LLDB merge.

I will be using the PR for cross-repo merge testing.

chandlerc and others added 23 commits November 1, 2016 13:38
This is a little class template that just builds an inheritance chain of
empty classes. Despite how simple this is, it can be used to really
nicely create ranked overload sets. I've added a unittest as much to
document this as test it. You can pass an object of this type as an
argument to a function overload set an it will call the first viable and
enabled candidate at or below the rank of the object.

I'm planning to use this in a subsequent commit to more clearly rank
overload candidates used for SFINAE. All credit for this technique and
both lines of code here to Richard Smith who was helping me rewrite the
SFINAE check in question to much more effectively capture the intended
set of checks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279197 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit d319716)
Reviewed By: majnemer, rnk
Differential Revision: https://reviews.llvm.org/D23965

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280114 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit bb0403b)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280117 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit b8d741f)
The name decided on was take_, but I only updated it for StringRef
and forgot to do it for ArrayRef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280126 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit b986a76)
If an attribute name has special characters such as '\01', it is not
properly printed in LLVM assembly language format.  Since the format
expects the special characters are printed as it is, it has to contain
escape characters to make it printable.

Before:
  attributes #0 = { ... "counting-function"="^A__gnu_mcount_nc" ...

After:
  attributes #0 = { ... "counting-function"="\01__gnu_mcount_nc" ...

Reviewers: hfinkel, rengolin, rjmccall, compnerd

Subscribers: nemanjai, mcrosier, hans, shenhan, majnemer, llvm-commits

Differential Revision: https://reviews.llvm.org/D23792

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@280357 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 89ea36c)
When porting large bodies of code from using const char*
to StringRef, it is helpful to be able to treat nullptr
as an empty string, since that it is often what it is used
to indicate in C-style code.

Differential Revision: https://reviews.llvm.org/D24697

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281906 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 781fb6e)
It's a guaranteed crash if you construct a StringRef with
nullptr, so might as well delete the constructor that allows
it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282116 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit ecdd589)
StringRef::getInteger() exists and treats the entire string as
an integer of the specified radix, failing if any invalid characters
are encountered or the number overflows.

Sometimes you might have something like "123456foo" and you want
to get the number 123456 and leave the string "foo" remaining.
This is similar to what would be possible by using the standard
runtime library functions strtoul et al and specifying an end
pointer.

This patch adds consumeInteger(), which does exactly that.  It
consumes as much as possible until an invalid character is found,
and modifies the StringRef in place so that upon return only
the portion of the StringRef after the number remains.

Differential Revision: https://reviews.llvm.org/D24778

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282164 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit fb27f55)
A recent patch added support for consumeInteger() and made
getAsInteger delegate to this function.  A few buildbots are
failing as a result with an assertion failure.  On a hunch,
I tested what happens if I call getAsInteger() on an empty
string, and sure enough it crashes the same way that the
buildbots are crashing.

I confirmed that getAsInteger() on an empty string did not
crash before my patch, so I suspect this to be the cause.

I also added a unit test for the empty string.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282170 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 20bb032)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282183 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 0966627)
This adds 4 new functions to StringRef, which can be used to
take or drop characters while a certain condition is met, or
until a certain condition is met.  They are:

take_while - Return characters until a condition is not met.
take_until - Return characters until a condition is met.
drop_while - Remove characters until a condition is not met.
drop_until - Remove characters until a condition is met.

Internally, all of these functions delegate to two additional
helper functions which can be used to search for the position
of a character meeting or not meeting a condition, which are:

find_if - Find the first character matching a predicate.
find_if_not - Find the first character not matching a predicate.

Differential Revision: https://reviews.llvm.org/D24842

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282346 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 568a8f4)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282348 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 3ae26e9)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282350 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 9f072db)
Differential Revision: https://reviews.llvm.org/D24904

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282433 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit bb748a1)
llvm::join_items is similar to llvm::join, which produces a string
by concatenating a sequence of values together separated by a
given separator.  But it differs in that the arguments to
llvm::join() are same-type members of a container, whereas the
arguments to llvm::join_items are arbitrary types passed into
a variadic template.  The only requirement on parameters to
llvm::join_items (including for the separator themselves) is
that they be implicitly convertible to std::string or have
an overload of std::string::operator+

Differential Revision: https://reviews.llvm.org/D24880

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282502 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit b93468a)
enumerate allows you to iterate over a range by pairing the
iterator's value with its index in the enumeration.  This gives
you most of the benefits of using a for loop while still allowing
the range syntax.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282804 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit ab82a45)
This reverts commit r282804 as it seems to use some C++ features
that not all compilers support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282809 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit a481451)
The CL was originally failing due to the use of some C++14
specific features, so I've removed those.  Hopefully this will
satisfy the bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@282867 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit f216a86)
This allows you to enumerate over a range using a range-based
for while the return type contains the index of the enumeration.

Differential revision: https://reviews.llvm.org/D25124

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283337 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 5844b06)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283342 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit e53904e)
Ten days.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283394 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 87bf019)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283395 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 81e3914)
This re-applies r283798, disabled in r283803, with the static_assert
tests disabled under MSVC. The deleted functions still seem to catch
mistakes in MSVC, so it's not a significant loss.

Part of rdar://problem/16375365

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283935 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 8f3f50a)
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tfiala commented Nov 1, 2016

Most of these changes are around llvm::StringRef.

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tfiala commented Nov 1, 2016

@fredriss, these are the cherry-picks I was referring to that I want to pull into the swift-3.1-branch branch of LLVM. The latest pull of upstream LLDB into the swift-lldb/master branch, which is in sync with the swift-3.1-branch of LLVM, makes heavy use of these. My options were to undo those changes in LLDB, or cherry-pick the small-ish set of underlying changes. I went for the latter, since that was the longer term right solution IMHO.

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fredriss commented Nov 1, 2016

@swift-ci please test

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fredriss commented Nov 2, 2016

@tfiala Do you think the test failures could be due to your cherry-picks?

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tfiala commented Nov 2, 2016

@fredriss having a look...

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tfiala commented Nov 2, 2016

Fast tracking this. I (mistakenly) committed the lldb side and forgot I needed this in. I'm going to see if the error shows up on a retest.

@swift-ci Please test OS X platform

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tfiala commented Nov 3, 2016

I reverted the merge in lldb that was depending on this a little while back.

I'm running the tests locally and seeing if one of these changes in llvm are causing the Swift failure. I also kicked off the macOS side again, just for another data point.

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tfiala commented Nov 3, 2016

I'm running the Swift test suite with this commit, and I'm not getting any failures. However, my test run is only picking up 3021 tests, not the 8000+ that I see in the output here:

Testing Time: 689.73s
  Expected Passes    : 2945
  Expected Failures  : 8
  Unsupported Tests  : 68
-- check-swift-macosx-x86_64 finished --
--- Finished tests for swift ---

So I may be missing the failing test case via another needed repo.

I'm now waiting on the macOS builder here to see what happens on the second run.

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tfiala commented Nov 3, 2016

Ah okay I looked into the failure a little deeper - it was specifically on the iPhone simulator. And the issue was what appeared to be a simulator error, not a test failure:

/Users/buildnode/jenkins/workspace/swift-llvm-PR-osx/swift/validation-test/Reflection/reflect_Int32.swift:32:14: error: expected string not found in input
// CHECK-32: Reflecting an object.
             ^
<stdin>:1:1: note: scanning from here
2016-11-01 16:17:48.888 simctl[69358:213162] CoreSimulatorService connection interrupted. Resubscribing to notifications.
^
<stdin>:1:67: note: possible intended match here
2016-11-01 16:17:48.888 simctl[69358:213162] CoreSimulatorService connection interrupted. Resubscribing to notifications.
                                                                  ^

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tfiala commented Nov 3, 2016

The failed Swift simulator test is flaky due to a simulator failure.

Merging as the second macOS run on CI worked fine.

@tfiala tfiala merged commit db16b4f into apple:swift-3.1-branch Nov 3, 2016
@tfiala tfiala deleted the for-lldb branch November 3, 2016 02:59
fredriss pushed a commit that referenced this pull request Dec 15, 2016
This is essentially a recommit of r285893, but with a correctness fix. The
problem of the original commit was that this:

bic r5, r7, #31
cbz r5, .LBB2_10

got rewritten into:

lsrs  r5, r7, #5
beq .LBB2_10

The result in destination register r5 is not the same and this is incorrect
when r5 is not dead. So this fix includes checking the uses of the AND
destination register. And also, compared to the original commit, some regression
tests didn't need changing anymore because of this extra check.

For completeness, this was the original commit message:

For the common pattern (CMPZ (AND x, #bitmask), #0), we can do some more
efficient instruction selection if the bitmask is one consecutive sequence of
set bits (32 - clz(bm) - ctz(bm) == popcount(bm)).

1) If the bitmask touches the LSB, then we can remove all the upper bits and
set the flags by doing one LSLS.
2) If the bitmask touches the MSB, then we can remove all the lower bits and
set the flags with one LSRS.
3) If the bitmask has popcount == 1 (only one set bit), we can shift that bit
into the sign bit with one LSLS and change the condition query from NE/EQ to
MI/PL (we could also implement this by shifting into the carry bit and
branching on BCC/BCS).
4) Otherwise, we can emit a sequence of LSLS+LSRS to remove the upper and lower
zero bits of the mask.

1-3 require only one 16-bit instruction and can elide the CMP. 4 requires two
16-bit instructions but can elide the CMP and doesn't require materializing a
complex immediate, so is also a win.

Differential Revision: https://reviews.llvm.org/D27761


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289794 91177308-0d34-0410-b5e6-96231b3b80d8
fredriss pushed a commit that referenced this pull request Jun 24, 2017
…for "free".

This patch contains a pass that transforms CBZ/CBNZ/TBZ/TBNZ instructions into a
conditional branch (Bcc), when the NZCV flags can be set for "free". This is
preferred on targets that have more flexibility when scheduling Bcc
instructions as compared to CBZ/CBNZ/TBZ/TBNZ (assuming all other variables are
equal). This can reduce register pressure and is also the default behavior for
GCC.

A few examples:

 add w8, w0, w1  -> cmn w0, w1             ; CMN is an alias of ADDS.
 cbz w8, .LBB_2  -> b.eq .LBB0_2           ; single def/use of w8 removed.

 add w8, w0, w1  -> adds w8, w0, w1        ; w8 has multiple uses.
 cbz w8, .LBB1_2 -> b.eq .LBB1_2

 sub w8, w0, w1       -> subs w8, w0, w1   ; w8 has multiple uses.
 tbz w8, #31, .LBB6_2 -> b.ge .LBB6_2

In looking at all current sub-target machine descriptions, this transformation
appears to be either positive or neutral.

Differential Revision: https://reviews.llvm.org/D34220.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@306144 91177308-0d34-0410-b5e6-96231b3b80d8
fredriss 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
adrian-prantl pushed a commit that referenced this pull request Jan 2, 2018
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
(cherry picked from commit d08f417)
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6 participants