Author: Orlando Cazalet-Hyams Date: 2025-06-04T10:53:29+01:00 New Revision: ac42923c2defe51fcc9220f68d50b33b5e872933
URL: https://github.com/llvm/llvm-project/commit/ac42923c2defe51fcc9220f68d50b33b5e872933 DIFF: https://github.com/llvm/llvm-project/commit/ac42923c2defe51fcc9220f68d50b33b5e872933.diff LOG: Reapply "[KeyInstr][Clang] For range stmt atoms" (#142630) This reverts commit e6529dcedb3955706a8af5710591f1ac1bac26a3 with crash fixed. Original PR https://github.com/llvm/llvm-project/pull/134647 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-range.cpp Modified: clang/lib/CodeGen/CGStmt.cpp Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp index 205a57cbab31a..dc92493ac70fa 100644 --- a/clang/lib/CodeGen/CGStmt.cpp +++ b/clang/lib/CodeGen/CGStmt.cpp @@ -1483,7 +1483,14 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S, if (!Weights && CGM.getCodeGenOpts().OptimizationLevel) 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. + if (auto *CondI = dyn_cast<llvm::Instruction>(BoolCondVal)) + addInstToNewSourceAtom(CondI, nullptr); + addInstToNewSourceAtom(I, nullptr); if (ExitBlock != LoopExit.getBlock()) { EmitBlock(ExitBlock); @@ -1508,6 +1515,9 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S, EmitStmt(S.getLoopVarStmt()); 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(); EmitStopPoint(&S); // If there is an increment, emit it next. @@ -1532,6 +1542,12 @@ CodeGenFunction::EmitCXXForRangeStmt(const CXXForRangeStmt &S, if (CGM.shouldEmitConvergenceTokens()) ConvergenceTokenStack.pop_back(); + + if (FinalBodyBB) { + // We want the for closing brace to be step-able on to match existing + // behaviour. + addInstToNewSourceAtom(FinalBodyBB->getTerminator(), nullptr); + } } void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) { diff --git a/clang/test/DebugInfo/KeyInstructions/for-range.cpp b/clang/test/DebugInfo/KeyInstructions/for-range.cpp new file mode 100644 index 0000000000000..433f900219f12 --- /dev/null +++ b/clang/test/DebugInfo/KeyInstructions/for-range.cpp @@ -0,0 +1,99 @@ +// RUN: %clang_cc1 -triple x86_64-linux-gnu -gkey-instructions %s -debug-info-kind=line-tables-only -emit-llvm -o - \ +// RUN: | FileCheck %s + +// Perennial question: should the inc be its own source atom or not +// (currently it is). + +// FIXME: See do.c and while.c regarding cmp and cond br groups. + +// The stores in the setup (stores to __RANGE1, __BEGIN1, __END1) are all +// marked as Key. Unclear whether that's desirable. Keep for now as that's +// least risky (at worst it introduces an unnecessary step while debugging, +// as opposed to potentially losing one we want). + +// Check the conditional branch (and the condition) in FOR_COND and +// unconditional branch in FOR_BODY are Key Instructions. + +struct Range { + int *begin(); + int *end(); +} r; + +// CHECK-LABEL: define dso_local void @_Z1av( +// CHECK-SAME: ) #[[ATTR0:[0-9]+]] !dbg [[DBG10:![0-9]+]] { +// CHECK-NEXT: [[ENTRY:.*:]] +// CHECK-NEXT: [[__RANGE1:%.*]] = alloca ptr, align 8 +// CHECK-NEXT: [[__BEGIN1:%.*]] = alloca ptr, align 8 +// CHECK-NEXT: [[__END1:%.*]] = alloca ptr, align 8 +// CHECK-NEXT: [[I:%.*]] = alloca i32, align 4 +// CHECK-NEXT: store ptr @r, ptr [[__RANGE1]], align 8, !dbg [[DBG14:![0-9]+]] +// CHECK-NEXT: [[CALL:%.*]] = call noundef ptr @_ZN5Range5beginEv(ptr noundef nonnull align 1 dereferenceable(1) @r), !dbg [[DBG15:![0-9]+]] +// CHECK-NEXT: store ptr [[CALL]], ptr [[__BEGIN1]], align 8, !dbg [[DBG16:![0-9]+]] +// CHECK-NEXT: [[CALL1:%.*]] = call noundef ptr @_ZN5Range3endEv(ptr noundef nonnull align 1 dereferenceable(1) @r), !dbg [[DBG17:![0-9]+]] +// CHECK-NEXT: store ptr [[CALL1]], ptr [[__END1]], align 8, !dbg [[DBG18:![0-9]+]] +// CHECK-NEXT: br label %[[FOR_COND:.*]], !dbg [[DBG19:![0-9]+]] +// CHECK: [[FOR_COND]]: +// CHECK-NEXT: [[TMP0:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]] +// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[__END1]], align 8, !dbg [[DBG19]] +// CHECK-NEXT: [[CMP:%.*]] = icmp ne ptr [[TMP0]], [[TMP1]], !dbg [[DBG20:![0-9]+]] +// CHECK-NEXT: br i1 [[CMP]], label %[[FOR_BODY:.*]], label %[[FOR_END:.*]], !dbg [[DBG21:![0-9]+]] +// CHECK: [[FOR_BODY]]: +// CHECK-NEXT: [[TMP2:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]] +// CHECK-NEXT: [[TMP3:%.*]] = load i32, ptr [[TMP2]], align 4, !dbg [[DBG22:![0-9]+]] +// CHECK-NEXT: store i32 [[TMP3]], ptr [[I]], align 4, !dbg [[DBG23:![0-9]+]] +// CHECK-NEXT: br label %[[FOR_INC:.*]], !dbg [[DBG24:![0-9]+]] +// CHECK: [[FOR_INC]]: +// CHECK-NEXT: [[TMP4:%.*]] = load ptr, ptr [[__BEGIN1]], align 8, !dbg [[DBG19]] +// CHECK-NEXT: [[INCDEC_PTR:%.*]] = getelementptr inbounds nuw i32, ptr [[TMP4]], i32 1, !dbg [[DBG25:![0-9]+]] +// CHECK-NEXT: store ptr [[INCDEC_PTR]], ptr [[__BEGIN1]], align 8, !dbg [[DBG26:![0-9]+]] +// CHECK-NEXT: br label %[[FOR_COND]], !dbg [[DBG19]], !llvm.loop +// CHECK: [[FOR_END]]: +// CHECK-NEXT: ret void, !dbg [[DBG30:![0-9]+]] +// +void a() { + for (int i: r) + ; +} + +// - Check the branch out of the body gets an atom group (and gets it correct +// if there's ctrl-flow in the body). +void b() { + for (int i: r) { + if (i) + ; +// CHECK: entry: +// CHECK: if.end: +// CHECK-NEXT: br label %for.inc, !dbg [[b_br:!.*]] + } +} + +// - Check an immediate loop exit (`break` in this case) gets an atom group and +// - doesn't cause a crash. +void c() { + for (int i: r) +// CHECK: entry: +// CHECK: for.body: +// CHECK: br label %for.end, !dbg [[c_br:!.*]] + break; +} + +//. +// CHECK: [[DBG14]] = !DILocation({{.*}}, atomGroup: 1, atomRank: 1) +// CHECK: [[DBG15]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 2) +// CHECK: [[DBG16]] = !DILocation({{.*}}, atomGroup: 2, atomRank: 1) +// CHECK: [[DBG17]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 2) +// CHECK: [[DBG18]] = !DILocation({{.*}}, atomGroup: 3, atomRank: 1) +// CHECK: [[DBG19]] = !DILocation({{.*}}) +// CHECK: [[DBG20]] = !DILocation({{.*}}, atomGroup: 4, atomRank: 1) +// CHECK: [[DBG21]] = !DILocation({{.*}}, atomGroup: 5, atomRank: 1) +// CHECK: [[DBG22]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 2) +// CHECK: [[DBG23]] = !DILocation({{.*}}, atomGroup: 6, atomRank: 1) +// CHECK: [[DBG24]] = !DILocation({{.*}} atomGroup: 8, atomRank: 1) +// CHECK: [[DBG25]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 2) +// CHECK: [[DBG26]] = !DILocation({{.*}}, atomGroup: 7, atomRank: 1) +// CHECK: [[DBG30]] = !DILocation({{.*}}) +// +// CHECK: [[b_br]] = !DILocation({{.*}}, atomGroup: [[#]], atomRank: [[#]]) +// +// CHECK: [[c_br]] = !DILocation({{.*}}, atomGroup: [[#]], atomRank: [[#]]) +//. _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
