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[KeyInstr][Clang] Assignment atom group (#134637)
This patch is part of a stack that teaches Clang to generate Key Instructions metadata for C and C++. RFC: 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.
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‎clang/lib/CodeGen/CGExpr.cpp

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@@ -5981,6 +5981,15 @@ LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
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assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
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// Create a Key Instructions source location atom group that covers both
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// LHS and RHS expressions. Nested RHS expressions may get subsequently
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// separately grouped (1 below):
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//
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// 1. `a = b = c` -> Two atoms.
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// 2. `x = new(1)` -> One atom (for both addr store and value store).
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// 3. Complex and agg assignment -> One atom.
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ApplyAtomGroup Grp(getDebugInfo());
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// Note that in all of these cases, __block variables need the RHS
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// evaluated first just in case the variable gets moved by the RHS.
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‎clang/lib/CodeGen/CGExprScalar.cpp

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@@ -898,6 +898,7 @@ class ScalarExprEmitter
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return result; \
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} \
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Value *VisitBin##OP##Assign(const CompoundAssignOperator *E) { \
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ApplyAtomGroup Grp(CGF.getDebugInfo()); \
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return EmitCompoundAssign(E, &ScalarExprEmitter::Emit##OP); \
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}
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HANDLEBINOP(Mul)
@@ -3014,6 +3015,7 @@ class OMPLastprivateConditionalUpdateRAII {
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llvm::Value *
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ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
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bool isInc, bool isPre) {
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ApplyAtomGroup Grp(CGF.getDebugInfo());
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OMPLastprivateConditionalUpdateRAII OMPRegion(CGF, E);
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QualType type = E->getSubExpr()->getType();
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llvm::PHINode *atomicPHI = nullptr;
@@ -5067,6 +5069,7 @@ llvm::Value *CodeGenFunction::EmitWithOriginalRHSBitfieldAssignment(
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}
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Value *ScalarExprEmitter::VisitBinAssign(const BinaryOperator *E) {
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ApplyAtomGroup Grp(CGF.getDebugInfo());
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bool Ignore = TestAndClearIgnoreResultAssign();
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Value *RHS;
@@ -5849,6 +5852,7 @@ LValue CodeGenFunction::EmitObjCIsaExpr(const ObjCIsaExpr *E) {
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LValue CodeGenFunction::EmitCompoundAssignmentLValue(
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const CompoundAssignOperator *E) {
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ApplyAtomGroup Grp(getDebugInfo());
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ScalarExprEmitter Scalar(*this);
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Value *Result = nullptr;
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switch (E->getOpcode()) {

‎clang/test/DebugInfo/KeyInstructions/assign-scalar.c

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// RUN: %clang_cc1 -gkey-instructions -x c++ %s -debug-info-kind=line-tables-only -emit-llvm -o - \
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// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
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// RUN: %clang_cc1 -gkey-instructions -x c %s -debug-info-kind=line-tables-only -emit-llvm -o - \
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// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
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unsigned long long g, h, i;
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void fun() {
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// CHECK: store i64 0, ptr @g{{.*}}, !dbg [[G1R1:!.*]]
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g = 0;
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// Treat the two assignments as two atoms.
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//
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// FIXME: Because of the atomGroup implementation the load can only be
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// associated with one of the two stores, despite being a good backup
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// loction for both.
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// CHECK-NEXT: %0 = load i64, ptr @g{{.*}}, !dbg [[G2R2:!.*]]
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// CHECK-NEXT: store i64 %0, ptr @g{{.*}}, !dbg [[G3R1:!.*]]
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// CHECK-NEXT: store i64 %0, ptr @g{{.*}}, !dbg [[G2R1:!.*]]
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g = g = g;
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// Compound assignment.
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// CHECK: %1 = load i64, ptr @g
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// CHECK: %add = add i64 %1, 50, !dbg [[G4R2:!.*]]
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// CHECK: store i64 %add, ptr @g{{.*}}, !dbg [[G4R1:!.*]]
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g += 50;
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// Pre/Post Inc/Dec.
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// CHECK: %2 = load i64, ptr @g
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// CHECK: %inc = add i64 %2, 1, !dbg [[G5R2:!.*]]
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// CHECK: store i64 %inc, ptr @g{{.*}}, !dbg [[G5R1:!.*]]
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++g;
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// CHECK: %3 = load i64, ptr @g
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// CHECK: %dec = add i64 %3, -1, !dbg [[G6R2:!.*]]
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// CHECK: store i64 %dec, ptr @g{{.*}}, !dbg [[G6R1:!.*]]
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g--;
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// Compound assignment with assignment on RHS, the assignments should have
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// their own separate atom groups.
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// CHECK-NEXT: %4 = load i64, ptr @h{{.*}}, !dbg [[load_h_loc:!.*]]
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// CHECK-NEXT: %inc1 = add i64 %4, 1, !dbg [[G8R2:!.*]]
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// CHECK-NEXT: store i64 %inc1, ptr @h{{.*}}, !dbg [[G8R1:!.*]]
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// CHECK-NEXT: %5 = load i64, ptr @g{{.*}}, !dbg [[load_g_loc:!.*]]
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// CHECK-NEXT: %add2 = add i64 %5, %inc1, !dbg [[G7R2:!.*]]
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// CHECK-NEXT: store i64 %add2, ptr @g{{.*}}, !dbg [[G7R1:!.*]]
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g += ++h;
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// Double check the comma operator doesn't disturb atom groupings. There
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// are three assignments, so we should get three groups.
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// FIXME: Same situation as earlier in the test - because of the atomGroup
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// implementation the load (from h) can only be associated with one of the two
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// stores (to h and g) despite being a good backup location for both.
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// CHECK-NEXT: %6 = load i64, ptr @h{{.*}}, !dbg [[load_h_loc2:!.*]]
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// CHECK-NEXT: %inc3 = add i64 %6, 1, !dbg [[G9R2:!.*]]
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// CHECK-NEXT: store i64 %inc3, ptr @h{{.*}}, !dbg [[G10R1:!.*]]
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// CHECK-NEXT: store i64 %inc3, ptr @g{{.*}}, !dbg [[G9R1:!.*]]
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// CHECK-NEXT: %7 = load i64, ptr @i{{.*}}, !dbg [[load_i_loc:!.*]]
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// CHECK-NEXT: %inc4 = add i64 %7, 1, !dbg [[G11R2:!.*]]
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// CHECK-NEXT: store i64 %inc4, ptr @i{{.*}}, !dbg [[G11R1:!.*]]
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g = ++h, ++i;
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}
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// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
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// CHECK: [[G2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
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// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
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// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
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// CHECK: [[G4R2]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 2)
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// CHECK: [[G4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1)
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// CHECK: [[G5R2]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 2)
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// CHECK: [[G5R1]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1)
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// CHECK: [[G6R2]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 2)
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// CHECK: [[G6R1]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 1)
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// CHECK: [[load_h_loc]] = !DILocation(line: [[#]], column: [[#]], scope: ![[#]])
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// CHECK: [[G8R2]] = !DILocation({{.*}}, atomGroup: 8, atomRank: 2)
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// CHECK: [[G8R1]] = !DILocation({{.*}}, atomGroup: 8, atomRank: 1)
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// CHECK: [[load_g_loc]] = !DILocation(line: [[#]], column: [[#]], scope: ![[#]])
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// CHECK: [[G7R2]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 2)
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// CHECK: [[G7R1]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 1)
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// CHECK: [[load_h_loc2]] = !DILocation(line: [[#]], column: [[#]], scope: ![[#]])
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// CHECK: [[G9R2]] = !DILocation({{.*}}, atomGroup: 9, atomRank: 2)
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// CHECK: [[G10R1]] = !DILocation({{.*}}, atomGroup: 10, atomRank: 1)
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// CHECK: [[G9R1]] = !DILocation({{.*}}, atomGroup: 9, atomRank: 1)
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// CHECK: [[load_i_loc]] = !DILocation(line: [[#]], column: [[#]], scope: ![[#]])
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// CHECK: [[G11R2]] = !DILocation({{.*}}, atomGroup: 11, atomRank: 2)
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// CHECK: [[G11R1]] = !DILocation({{.*}}, atomGroup: 11, atomRank: 1)

‎clang/test/DebugInfo/KeyInstructions/init-agg.c

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// RUN: %clang -gkey-instructions -x c++ %s -gmlt -gno-column-info -S -emit-llvm -o - -ftrivial-auto-var-init=pattern \
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// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
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// RUN: %clang -gkey-instructions -x c %s -gmlt -gno-column-info -S -emit-llvm -o - -ftrivial-auto-var-init=pattern \
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// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank
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// The implicit-check-not is important; we don't want the GEPs created for the
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// store locations to be included in the atom group.
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int g;
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void a() {
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// CHECK: call void @llvm.memcpy{{.*}}%A{{.*}}, !dbg [[G1R1:!.*]]
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int A[] = { 1, 2, 3 };
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// CHECK: store i32 1, ptr %{{.*}}, !dbg [[G2R1:!.*]]
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// CHECK: store i32 2, ptr %{{.*}}, !dbg [[G2R1]]
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// CHECK: %0 = load i32, ptr @g{{.*}}, !dbg [[G2R2:!.*]]
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// CHECK: store i32 %0, ptr %{{.*}}, !dbg [[G2R1]]
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int B[] = { 1, 2, g };
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// CHECK: call void @llvm.memset{{.*}}%big{{.*}}, !dbg [[G3R1:!.*]]
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// CHECK: store i8 97{{.*}}, !dbg [[G3R1]]
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// CHECK: store i8 98{{.*}}, !dbg [[G3R1]]
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// CHECK: store i8 99{{.*}}, !dbg [[G3R1]]
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// CHECK: store i8 100{{.*}}, !dbg [[G3R1]]
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char big[65536] = { 'a', 'b', 'c', 'd' };
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// CHECK: call void @llvm.memset{{.*}}%arr{{.*}}, !dbg [[G4R1:!.*]]
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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, };
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// CHECK: store i8 -86, ptr %uninit{{.*}}, !dbg [[G5R1:!.*]], !annotation
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char uninit; // -ftrivial-auto-var-init=pattern
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}
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// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1)
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// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1)
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// CHECK: [[G2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2)
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// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1)
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// CHECK: [[G4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1)
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// CHECK: [[G5R1]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1)

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