Author: Orlando Cazalet-Hyams Date: 2025-08-27T09:49:40+01:00 New Revision: 9d65f7715995e69bf487a7c97523244c4ca5269f
URL: https://github.com/llvm/llvm-project/commit/9d65f7715995e69bf487a7c97523244c4ca5269f DIFF: https://github.com/llvm/llvm-project/commit/9d65f7715995e69bf487a7c97523244c4ca5269f.diff LOG: [KeyInstr] Enable -gkey-instructions by default if optimisations are enabled (#149509) That's enabling Clang's -gkey-instructions, cc1's -gkey-instructions remains off by default. Key Instructions improves the optimized-code debug-stepping experience in debuggers that use DWARF's `is_stmt` line table register to determine stepping behaviour. The feature can be disabled with -gno-key-instructions (note that the positive and negative flag both imply -g). RFC: https://discourse.llvm.org/t/rfc-improving-is-stmt-placement-for-better-interactive-debugging/82668 Added: Modified: clang/lib/Driver/ToolChains/Clang.cpp clang/test/DebugInfo/KeyInstructions/flag.cpp Removed: ################################################################################ diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 1b44090534e82..d22feae6bc6ea 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -4394,10 +4394,15 @@ static void renderDwarfFormat(const Driver &D, const llvm::Triple &T, static void renderDebugOptions(const ToolChain &TC, const Driver &D, const llvm::Triple &T, - const ArgList &Args, bool IRInput, ArgStringList &CmdArgs, - const InputInfo &Output, + const ArgList &Args, types::ID InputType, + ArgStringList &CmdArgs, const InputInfo &Output, llvm::codegenoptions::DebugInfoKind &DebugInfoKind, DwarfFissionKind &DwarfFission) { + bool IRInput = isLLVMIR(InputType); + bool PlainCOrCXX = isDerivedFromC(InputType) && !isCuda(InputType) && + !isHIP(InputType) && !isObjC(InputType) && + !isOpenCL(InputType); + if (Args.hasFlag(options::OPT_fdebug_info_for_profiling, options::OPT_fno_debug_info_for_profiling, false) && checkDebugInfoOption( @@ -4591,8 +4596,15 @@ renderDebugOptions(const ToolChain &TC, const Driver &D, const llvm::Triple &T, CmdArgs.push_back("-gembed-source"); } + // Enable Key Instructions by default if we're emitting DWARF, the language is + // plain C or C++, and optimisations are enabled. + Arg *OptLevel = Args.getLastArg(options::OPT_O_Group); + bool KeyInstructionsOnByDefault = + EmitDwarf && PlainCOrCXX && OptLevel && + !OptLevel->getOption().matches(options::OPT_O0); if (Args.hasFlag(options::OPT_gkey_instructions, - options::OPT_gno_key_instructions, false)) + options::OPT_gno_key_instructions, + KeyInstructionsOnByDefault)) CmdArgs.push_back("-gkey-instructions"); if (EmitCodeView) { @@ -6060,8 +6072,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, llvm::codegenoptions::DebugInfoKind DebugInfoKind = llvm::codegenoptions::NoDebugInfo; DwarfFissionKind DwarfFission = DwarfFissionKind::None; - renderDebugOptions(TC, D, RawTriple, Args, types::isLLVMIR(InputType), - CmdArgs, Output, DebugInfoKind, DwarfFission); + renderDebugOptions(TC, D, RawTriple, Args, InputType, CmdArgs, Output, + DebugInfoKind, DwarfFission); // Add the split debug info name to the command lines here so we // can propagate it to the backend. diff --git a/clang/test/DebugInfo/KeyInstructions/flag.cpp b/clang/test/DebugInfo/KeyInstructions/flag.cpp index e34faa6cbb347..a5cd8558eae52 100644 --- a/clang/test/DebugInfo/KeyInstructions/flag.cpp +++ b/clang/test/DebugInfo/KeyInstructions/flag.cpp @@ -1,7 +1,5 @@ // RUN: %clang -### -target x86_64 -c -gdwarf -gkey-instructions %s 2>&1 | FileCheck %s --check-prefixes=KEY-INSTRUCTIONS // RUN: %clang -### -target x86_64 -c -gdwarf -gno-key-instructions %s 2>&1 | FileCheck %s --check-prefixes=NO-KEY-INSTRUCTIONS -//// Default: Off. -// RUN: %clang -### -target x86_64 -c -gdwarf %s 2>&1 | FileCheck %s --check-prefixes=NO-KEY-INSTRUCTIONS //// Help. // RUN %clang --help | FileCheck %s --check-prefix=HELP @@ -23,3 +21,43 @@ void f() {} // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -gkey-instructions -debug-info-kind=line-tables-only -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-ON // SMOKETEST-ON: keyInstructions: true // SMOKETEST-ON: atomGroup: 1 + +//// Enable Key Instructions by default if optimisations are enabled and we're +//// emitting DWARF. +//// +//// | opt level | -gkey-instructions | feature | +//// | 0 | no | off | +//// | 0 | yes | on | +//// | >=1 | no | on | +//// | >=1 | yes | on | +//// | >=1 | no & no -g flags | off | +//// | >=1 | no & emit codeview | off | +// +// RUN: %clang %s -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang %s -target x86_64 -gdwarf -gmlt -gkey-instructions -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang %s -O0 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang %s -O0 -target x86_64 -gdwarf -gmlt -gkey-instructions -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang %s -O1 -target x86_64 -gdwarf -gmlt -gkey-instructions -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang %s -O1 -target x86_64 -### 2>&1 | FileCheck %s --check-prefixes=NO-KEY-INSTRUCTIONS +// RUN: %clang %s -O1 -target x86_64 -gcodeview -gmlt -### 2>&1 | FileCheck %s --check-prefixes=NO-KEY-INSTRUCTIONS +// +// RUN: %clang %s -target x86_64 -gdwarf -gmlt -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-OFF +// RUN: %clang %s -target x86_64 -gdwarf -gmlt -gkey-instructions -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-ON +// RUN: %clang %s -O0 -target x86_64 -gdwarf -gmlt -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-OFF +// RUN: %clang %s -O0 -target x86_64 -gdwarf -gmlt -gkey-instructions -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-ON +// RUN: %clang %s -O1 -target x86_64 -gdwarf -gmlt -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-ON +// RUN: %clang %s -O1 -target x86_64 -gdwarf -gmlt -gkey-instructions -S -emit-llvm -o - | FileCheck %s --check-prefix=SMOKETEST-ON +// RUN: %clang %s -O1 -target x86_64 -S -emit-llvm -o - | FileCheck %s --check-prefixes=SMOKETEST-OFF,SMOKETEST-NO-DEBUG +// RUN: %clang %s -O1 -target x86_64 -gcodeview -gmlt -S -emit-llvm -o - | FileCheck %s --check-prefixes=SMOKETEST-OFF +// SMOKETEST-NO-DEBUG: llvm.module.flags +// SMOKETEST-NO-DEBUG-NOT: DICompileUnit + +//// Check only "plain" C/C++ turns on Key Instructions by default. +// RUN: %clang -x c %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang -x c++ %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=KEY-INSTRUCTIONS +// RUN: %clang -x cuda -nocudalib -nocudainc %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang -x hip -nogpulib -nogpuinc %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang -x cl %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang -x objective-c %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS +// RUN: %clang -x objective-c++ %s -O1 -target x86_64 -gdwarf -gmlt -### 2>&1 | FileCheck %s --check-prefix=NO-KEY-INSTRUCTIONS _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
