Author: Orlando Cazalet-Hyams Date: 2025-05-23T14:42:28+01:00 New Revision: 6bd3543a4d2977cb63f7212594ea0f2ac6e8ab12
URL: https://github.com/llvm/llvm-project/commit/6bd3543a4d2977cb63f7212594ea0f2ac6e8ab12 DIFF: https://github.com/llvm/llvm-project/commit/6bd3543a4d2977cb63f7212594ea0f2ac6e8ab12.diff LOG: [KeyInstr][Clang] While stmt atom (#134645) See test comment for possible future improvement. 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/while.c Modified: clang/lib/CodeGen/CGStmt.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index ca1e6522ad564..3b701116e5e4b 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -1130,7 +1130,15 @@ void CodeGenFunction::EmitWhileStmt(const WhileStmt &S, if (!Weights && CGM.getCodeGenOpts().OptimizationLevel) BoolCondVal = emitCondLikelihoodViaExpectIntrinsic( BoolCondVal, Stmt::getLikelihood(S.getBody())); - Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights); + auto *I = Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock, Weights); + // Key Instructions: Emit the condition and branch as separate source + // location atoms otherwise we may omit a step onto the loop condition in + // favour of the `while` keyword. + // FIXME: We could have the branch as the backup location for the condition, + // which would probably be a better experience. Explore this later. + if (auto *CondI = dyn_cast<llvm::Instruction>(BoolCondVal)) + addInstToNewSourceAtom(CondI, nullptr); + addInstToNewSourceAtom(I, nullptr); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); diff --git a/clang/test/DebugInfo/KeyInstructions/while.c b/clang/test/DebugInfo/KeyInstructions/while.c new file mode 100644 index 0000000000000..fc65abf5155d5 --- /dev/null +++ b/clang/test/DebugInfo/KeyInstructions/while.c @@ -0,0 +1,34 @@ +// RUN: %clang_cc1 -gkey-instructions -x c++ -std=c++17 %s -debug-info-kind=line-tables-only -emit-llvm -o - \ +// RUN: | FileCheck %s --implicit-check-not atomGroup --implicit-check-not atomRank + +// RUN: %clang_cc1 -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 `dec` be in its own source atom or not +// (currently it is). + +// We've made the cmp and br separate source atoms for now, to match existing +// behaviour in this case: +// 1. while ( +// 2. int i = --End +// 3. ) { +// 4. useValue(i); +// 5. } +// Without Key Instructions we go: 2, 1[, 4, 2, 1]+ +// Without separating cmp and br with Key Instructions we'd get: +// 1[, 4, 1]+. If we made the cmp higher precedence than the +// br and had them in the same group, we could get: +// 2, [4, 2]+ which might be nicer. FIXME: do that later. + +void a(int A) { +// CHECK: %dec = add nsw i32 %0, -1, !dbg [[G1R2:!.*]] +// CHECK: store i32 %dec, ptr %A.addr{{.*}}, !dbg [[G1R1:!.*]] +// CHECK: %tobool = icmp ne i32 %dec, 0, !dbg [[G2R1:!.*]] +// CHECK: br i1 %tobool, label %while.body, label %while.end, !dbg [[G3R1:!.*]] + while (--A) { }; +} + +// CHECK: [[G1R2]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 2) +// CHECK: [[G1R1]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[G2R1]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) +// CHECK: [[G3R1]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1) _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
