[KeyInstr][Clang] Agg init atom

[OCHyams]

[KeyInstr][Clang] Agg init atom

This patch is part of a stack that teaches Clang to generate Key Instructions
metadata for C and C++.

The Key Instructions project is introduced, including a "quick summary" section
at the top which adds context for this PR, here:
https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668

The feature is only functional in LLVM if LLVM is built with CMake flag
LLVM_EXPERIMENTAL_KEY_INSTRUCTIONs. Eventually that flag will be removed.

The Clang-side work is demoed here:
#130943

shouldUseBZeroPlusStoresToInitialize

[KeyInstr] init-agg pattern

[KeyInstr][Clang] Init pattern atom

[llvmbot]

@llvm/pr-subscribers-clang-codegen

@llvm/pr-subscribers-clang

Author: Orlando Cazalet-Hyams (OCHyams)

Changes

[KeyInstr][Clang] Agg init atom

This patch is part of a stack that teaches Clang to generate Key Instructions
metadata for C and C++.

The Key Instructions project is introduced, including a "quick summary" section
at the top which adds context for this PR, here:
https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668

The feature is only functional in LLVM if LLVM is built with CMake flag
LLVM_EXPERIMENTAL_KEY_INSTRUCTIONs. Eventually that flag will be removed.

The Clang-side work is demoed here:
#130943

shouldUseBZeroPlusStoresToInitialize

[KeyInstr] init-agg pattern

[KeyInstr][Clang] Init pattern atom

---

Full diff: https://github.com/llvm/llvm-project/pull/134635.diff

2 Files Affected:

• (modified) clang/lib/CodeGen/CGDecl.cpp (+7)
• (added) clang/test/KeyInstructions/init-agg.cpp (+39)

diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp
index 6aa9f3fa27c87..9860ab0b033bb 100644
--- a/clang/lib/CodeGen/CGDecl.cpp
+++ b/clang/lib/CodeGen/CGDecl.cpp
@@ -938,6 +938,7 @@ void CodeGenFunction::emitStoresForInitAfterBZero(llvm::Constant *Init,
       isa<llvm::ConstantVector>(Init) || isa<llvm::BlockAddress>(Init) ||
       isa<llvm::ConstantExpr>(Init)) {
     auto *I = Builder.CreateStore(Init, Loc, isVolatile);
+    addInstToCurrentSourceAtom(I, nullptr);
     if (IsAutoInit)
       I->addAnnotationMetadata("auto-init");
     return;
@@ -1181,6 +1182,7 @@ void CodeGenFunction::emitStoresForConstant(const VarDecl &D, Address Loc,
                           Ty->isPtrOrPtrVectorTy() || Ty->isFPOrFPVectorTy();
   if (canDoSingleStore) {
     auto *I = Builder.CreateStore(constant, Loc, isVolatile);
+    addInstToCurrentSourceAtom(I, nullptr);
     if (IsAutoInit)
       I->addAnnotationMetadata("auto-init");
     return;
@@ -1193,6 +1195,8 @@ void CodeGenFunction::emitStoresForConstant(const VarDecl &D, Address Loc,
   if (shouldUseBZeroPlusStoresToInitialize(constant, ConstantSize)) {
     auto *I = Builder.CreateMemSet(Loc, llvm::ConstantInt::get(CGM.Int8Ty, 0),
                                    SizeVal, isVolatile);
+    addInstToCurrentSourceAtom(I, nullptr);
+
     if (IsAutoInit)
       I->addAnnotationMetadata("auto-init");
 
@@ -1217,6 +1221,7 @@ void CodeGenFunction::emitStoresForConstant(const VarDecl &D, Address Loc,
     }
     auto *I = Builder.CreateMemSet(
         Loc, llvm::ConstantInt::get(CGM.Int8Ty, Value), SizeVal, isVolatile);
+    addInstToCurrentSourceAtom(I, nullptr);
     if (IsAutoInit)
       I->addAnnotationMetadata("auto-init");
     return;
@@ -1263,6 +1268,8 @@ void CodeGenFunction::emitStoresForConstant(const VarDecl &D, Address Loc,
                            createUnnamedGlobalForMemcpyFrom(
                                CGM, D, Builder, constant, Loc.getAlignment()),
                            SizeVal, isVolatile);
+  addInstToCurrentSourceAtom(I, nullptr);
+
   if (IsAutoInit)
     I->addAnnotationMetadata("auto-init");
 }
diff --git a/clang/test/KeyInstructions/init-agg.cpp b/clang/test/KeyInstructions/init-agg.cpp
new file mode 100644
index 0000000000000..f0cc67e659d95
--- /dev/null
+++ b/clang/test/KeyInstructions/init-agg.cpp
@@ -0,0 +1,39 @@
+
+// RUN: %clang -gkey-instructions %s -gmlt -gno-column-info -S -emit-llvm -o - -ftrivial-auto-var-init=pattern \
+// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
+
+// The implicit-check-not is important; we don't want the GEPs created for the
+// store locations to be included in the atom group.
+
+int g;
+void a() {
+// CHECK: _Z1av()
+// CHECK: call void @llvm.memcpy{{.*}}, !dbg [[G1R1:!.*]]
+    int A[] = { 1, 2, 3 };
+
+// CHECK: store i32 1, ptr %{{.*}}, !dbg [[G2R1:!.*]]
+// CHECK: store i32 2, ptr %{{.*}}, !dbg [[G2R1]]
+// CHECK: %0 = load i32, ptr @g{{.*}}, !dbg [[G2R2:!.*]]
+// CHECK: store i32 %0, ptr %{{.*}}, !dbg [[G2R1]]
+    int B[] = { 1, 2, g };
+
+// CHECK: call void @llvm.memset{{.*}}, !dbg [[G3R1:!.*]]
+// CHECK: store i8 97{{.*}}, !dbg [[G3R1]]
+// CHECK: store i8 98{{.*}}, !dbg [[G3R1]]
+// CHECK: store i8 99{{.*}}, !dbg [[G3R1]]
+// CHECK: store i8 100{{.*}}, !dbg [[G3R1]]
+    char big[65536] = { 'a', 'b', 'c', 'd' };
+
+// CHECK: call void @llvm.memset{{.*}}, !dbg [[G4R1:!.*]]
+    char arr[] = { 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, };
+
+// CHECK: store i8 -86, ptr %uninit{{.*}}, !dbg [[G5R1:!.*]], !annotation
+    char uninit; // -ftrivial-auto-var-init=pattern
+}
+
+// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
+// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
+// CHECK: [[G2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
+// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
+// CHECK: [[G4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1)
+// CHECK: [[G5R1]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1)

[OCHyams]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• [NFC][KeyInstr][Clang] Add some additional tests #134654
• [KeyInstr][Clang] Coerced store atoms #134653
• [KeyInstr][Clang] Ret atom #134652
• [KeyIntsr][Clang] Builtins alloca auto-init atom #134651
• [KeyInstr][Clang] Assign matrix element atom #134650
• [KeyInstr][Clang] Assign vector element atom #134649
• [KeyInstr][Clang] Bitfield atom #134648
• [KeyInstr][Clang] For range stmt atoms #134647
• [KeyInstr][Clang] For stmt atom #134646
• [KeyInstr][Clang] While stmt atom #134645
• [KeyInstr][Clang] Do stmt atom #134644
• [KeyInstr][Clang] Switch stmt atom #134643
• [KeyInstr][Clang] If stmt atom #134642
• [KeyInstr][Clang] Catch variable init atom #134641
• [KeyInstr][Clang] Member initalization atom #134640
• [KeyInstr][Clang] Aggregate init + copy #134639
• [KeyInstr] Complex assignment atoms #134638
• [KeyInstr][Clang] Assignment atom group #134637
• [KeyInstr][Clang] Static variable init atom #134636
• [KeyInstr][Clang] Agg init atom #134635 👈 (View in Graphite)
• [Clang][NFC] Move some static functions into CodeGenFunction #134634
• [KeyInstr][Clang] Scalar init atom #134633
• [KeyInstr][Clang] Add ApplyAtomGroup #134632
• [KeyInstr][Clang] Add Clang option -g[no-]key-instructions #134627
• [KeyInstr][DwarfDebug] Add is_stmt emission support #133495
• [KeyInstr] Add MIR parser support #133494
• [KeyInstr] Remap cloned PHIs in BreakCriticalEdges #133493
• Propagate DebugLocs on phis in BreakCriticalEdges #133492
• [KeyInstr][LoopUnswitch] Remap cloned instructions' atoms #133491
• [KeyInstr][LoopRotate] Remap atoms of duplicated instructions #133490
• [KeyInstr][LoopUnroll] Remap atoms while unrolling #133489
• [KeyInstr][JumpThreading] Remap atoms duping bb with cond br on phi into pred #133488
• [KeyInstr][JumpThreading] Remap atoms after threading #133487
• [KeyInstr][JumpThreading] Remap atoms in blocks duplicated for threading #133486
• [KeyInstr][Inline] Don't propagate atoms to inlined nodebug instructions #133485
• [KeyInstr][SimplifyCFG] Remap atoms after duplication for threading #133484
• [KeyInstr][debugify] Add --debugify-atoms to add key instructions metadata #133483
• [KeyInstr][SimplifyCFG] Remap atoms when folding br to common succ into pred #133482
• [KeyInstr] Inline atom info #133481
• [KeyInstr] Merge atoms in DILocation::getMergedLocation #133480
• [NFC][KeyInstr] Add Atom Group (re)mapping #133479
• [KeyInstr] Add Atom Group waterline to LLVMContext #133478
• [KeyInstr] Add fields to DILocation behind compile time flag #133477
• main

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