Author: Orlando Cazalet-Hyams Date: 2025-06-03T13:47:32+01:00 New Revision: 0555594195c8a39ea3469fb4ded211960fde385b
URL: https://github.com/llvm/llvm-project/commit/0555594195c8a39ea3469fb4ded211960fde385b DIFF: https://github.com/llvm/llvm-project/commit/0555594195c8a39ea3469fb4ded211960fde385b.diff LOG: [KeyInstr][Clang] For stmt atom (#134646) 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. Added: clang/test/DebugInfo/KeyInstructions/for.c Modified: clang/lib/CodeGen/CGStmt.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index 2ae7372211fa4..d890bdcb2dd29 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -1365,7 +1365,14 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S, BoolCondVal = emitCondLikelihoodViaExpectIntrinsic( BoolCondVal, Stmt::getLikelihood(S.getBody())); - Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights); + auto *I = Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock, Weights); + // Key Instructions: Emit the condition and branch as separate atoms to + // match existing loop stepping behaviour. FIXME: We could have the branch + // as the backup location for the condition, which would probably be a + // better experience (no jumping to the brace). + if (auto *CondI = dyn_cast<llvm::Instruction>(BoolCondVal)) + addInstToNewSourceAtom(CondI, nullptr); + addInstToNewSourceAtom(I, nullptr); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); @@ -1390,6 +1397,10 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S, EmitStmt(S.getBody()); } + // The last block in the loop's body (which unconditionally branches to the + // `inc` block if there is one). + auto *FinalBodyBB = Builder.GetInsertBlock(); + // If there is an increment, emit it next. if (S.getInc()) { EmitBlock(Continue.getBlock()); @@ -1419,6 +1430,12 @@ void CodeGenFunction::EmitForStmt(const ForStmt &S, if (CGM.shouldEmitConvergenceTokens()) ConvergenceTokenStack.pop_back(); + + if (FinalBodyBB) { + // Key Instructions: We want the for closing brace to be step-able on to + // match existing behaviour. + addInstToNewSourceAtom(FinalBodyBB->getTerminator(), nullptr); + } } void diff --git a/clang/test/DebugInfo/KeyInstructions/for.c b/clang/test/DebugInfo/KeyInstructions/for.c new file mode 100644 index 0000000000000..b42a74a639b97 --- /dev/null +++ b/clang/test/DebugInfo/KeyInstructions/for.c @@ -0,0 +1,145 @@ +// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions -x c++ %s -debug-info-kind=line-tables-only -emit-llvm -o - \ +// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank + +// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions -x c %s -debug-info-kind=line-tables-only -emit-llvm -o - \ +// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank + +// Perennial question: should the inc be its own source atom or not +// (currently it is). + +// TODO: See do.c and while.c regarding cmp and cond br groups. + +void a(int A) { +// CHECK: entry: +// CHECK: store i32 0, ptr %i{{.*}}, !dbg [[G1R1:!.*]] +// CHECK: for.cond: +// CHECK: %cmp = icmp slt i32 %0, %1, !dbg [[G2R1:!.*]] +// CHECK: br i1 %cmp, label %for.body, label %for.end, !dbg [[G3R1:!.*]] + +// TODO: The unconditional br is given an atom group here which is useful for +// O0. Since we're no longer targeting O0 we should reevaluate whether this +// adds any value. +// CHECK: for.body: +// CHECK-NEXT: br label %for.inc, !dbg [[G5R1:!.*]] + +// CHECK: for.inc: +// CHECK: %inc = add{{.*}}, !dbg [[G4R2:!.*]] +// CHECK: store i32 %inc, ptr %i{{.*}}, !dbg [[G4R1:!.*]] + for (int i = 0; i < A; ++i) { + } +} + +void b(int A) { +// CHECK: entry: +// CHECK: store i32 0, ptr %i{{.*}}, !dbg [[bG1R1:!.*]] +// CHECK: for.cond: +// CHECK: %cmp = icmp slt i32 %0, %1, !dbg [[bG2R1:!.*]] +// CHECK: br i1 %cmp, label %for.body, label %for.end, !dbg [[bG3R1:!.*]] + +// CHECK: for.body: +// CHECK-NEXT: %2 = load i32, ptr %A.addr +// - If stmt atom: +// CHECK-NEXT: %cmp1 = icmp sgt i32 %2, 1, !dbg [[bG4R2:!.*]] +// CHECK-NEXT: br i1 %cmp1, label %if.then, label %if.end, !dbg [[bG4R1:!.*]] +// CHECK: if.then: +// CHECK-NEXT: br label %if.end + +// - For closing brace. +// CHECK: if.end: +// CHECK-NEXT: br label %for.inc, !dbg [[bG6R1:!.*]] + +// CHECK: for.inc: +// CHECK: %inc = add{{.*}}, !dbg [[bG5R2:!.*]] +// CHECK: store i32 %inc, ptr %i{{.*}}, !dbg [[bG5R1:!.*]] + for (int i = 0; i < A; ++i) { + if (A > 1) + ; + } +} + +void c(int A) { +// CHECK: entry: +// CHECK: for.cond: +// CHECK-NEXT: %0 = load i32, ptr %A.addr +// - If stmt atom: +// CHECK-NEXT: %cmp = icmp sgt i32 %0, 1, !dbg [[cG1R2:!.*]] +// CHECK-NEXT: br i1 %cmp, label %if.then, label %if.end, !dbg [[cG1R1:!.*]] +// CHECK: if.then: +// CHECK-NEXT: br label %if.end + +// - For closing brace. +// CHECK: if.end: +// CHECK-NEXT: br label %for.inc, !dbg [[cG3R1:!.*]] + +// CHECK: for.inc: +// CHECK-NEXT: %1 = load i32, ptr %A.addr +// CHECK-NEXT: %inc = add{{.*}}, !dbg [[cG2R2:!.*]] +// CHECK-NEXT: store i32 %inc, ptr %A.addr{{.*}}, !dbg [[cG2R1:!.*]] + for (; /*no cond*/ ; ++A) { + if (A > 1) + ; + } +} + +void d() { +// - Check the `for` keyword gets an atom group. +// CHECK: entry: +// CHECK-NEXT: br label %for.cond + +// CHECK: for.cond: +// CHECK: br label %for.cond, !dbg [[dG1R1:!.*]], !llvm.loop + for ( ; ; ) + { + } +} + +int x, i; +void ee(); +void e() { +// - Check we assign an atom group to `for.body`s `br`, even without braces. +// - TODO: Investigate whether this is needed. +// CHECK: entry: + +// CHECK: for.cond: +// CHECK-NEXT: %0 = load i32, ptr @i +// CHECK-NEXT: %cmp = icmp slt i32 %0, 3, !dbg [[eG1R1:!.*]] +// CHECK-NEXT: br i1 %cmp, label %for.body, label %for.end, !dbg [[eG2R1:!.*]] + +// CHECK: for.body: +// CHECK-NEXT: %1 = load i32, ptr @i{{.*}}, !dbg [[eG3R2:!.*]] +// CHECK-NEXT: store i32 %1, ptr @x{{.*}}, !dbg [[eG3R1:!.*]] +// CHECK-NEXT: br label %for.inc, !dbg [[eG4R1:!.*]] + for (; i < 3; ee()) + x = i; +} + + +// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) +// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1) +// CHECK: [[G5R1]] = !DILocation(line: 29,{{.*}} atomGroup: 5, atomRank: 1) +// CHECK: [[G4R2]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 2) +// CHECK: [[G4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1) + +// CHECK: [[bG1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[bG2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) +// CHECK: [[bG3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1) +// CHECK: [[bG4R2]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 2) +// CHECK: [[bG4R1]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1) +// CHECK: [[bG6R1]] = !DILocation(line: 57,{{.*}} atomGroup: 6, atomRank: 1) +// CHECK: [[bG5R2]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 2) +// CHECK: [[bG5R1]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1) + +// CHECK: [[cG1R2]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 2) +// CHECK: [[cG1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[cG3R1]] = !DILocation(line: 81,{{.*}} atomGroup: 3, atomRank: 1) +// CHECK: [[cG2R2]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2) +// CHECK: [[cG2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) + +// CHECK: [[dG1R1]] = !DILocation(line: 91, column: 3, scope: ![[#]], atomGroup: 1, atomRank: 1) + +// CHECK: [[eG1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[eG2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) +// CHECK: [[eG3R2]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 2) +// CHECK: [[eG3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1) +// CHECK: [[eG4R1]] = !DILocation(line: 113, column: 5, scope: ![[#]], atomGroup: 4, atomRank: 1) _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
