From 14e8a5a32d8f34b5154f24072fb7a8803ea52ae3 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Tue, 21 Nov 2017 17:30:34 +0000 Subject: [PATCH] Add -finstrument-function-entry-bare flag This is an instrumentation flag that's similar to -finstrument-functions, but it only inserts calls on function entry, the calls are inserted post-inlining, and they don't take any arugments. This is intended for users who want to instrument function entry with minimal overhead. (-pg would be another alternative, but forces frame pointer emission and affects link flags, so is probably best left alone to be used for generating gcov data.) Differential revision: https://reviews.llvm.org/D40276 llvm-svn: 318785 --- clang/include/clang/Driver/Options.td | 2 ++ clang/include/clang/Frontend/CodeGenOptions.def | 2 ++ clang/lib/CodeGen/CodeGenFunction.cpp | 24 +++++++++++++++--------- clang/lib/Driver/ToolChains/Clang.cpp | 7 +++++-- clang/lib/Frontend/CompilerInvocation.cpp | 2 ++ clang/test/CodeGen/instrument-functions.c | 13 +++++++++++++ 6 files changed, 39 insertions(+), 11 deletions(-) diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 841087e..2ca6f47 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -1030,6 +1030,8 @@ def finstrument_functions : Flag<["-"], "finstrument-functions">, Group HelpText<"Generate calls to instrument function entry and exit">; def finstrument_functions_after_inlining : Flag<["-"], "finstrument-functions-after-inlining">, Group, Flags<[CC1Option]>, HelpText<"Like -finstrument-functions, but insert the calls after inlining">; +def finstrument_function_entry_bare : Flag<["-"], "finstrument-function-entry-bare">, Group, Flags<[CC1Option]>, + HelpText<"Instrument function entry only, after inlining, without arguments to the instrumentation call">; def fxray_instrument : Flag<["-"], "fxray-instrument">, Group, Flags<[CC1Option]>, diff --git a/clang/include/clang/Frontend/CodeGenOptions.def b/clang/include/clang/Frontend/CodeGenOptions.def index efc656a..e555505 100644 --- a/clang/include/clang/Frontend/CodeGenOptions.def +++ b/clang/include/clang/Frontend/CodeGenOptions.def @@ -78,6 +78,8 @@ CODEGENOPT(InstrumentFunctions , 1, 0) ///< Set when -finstrument-functions is ///< enabled. CODEGENOPT(InstrumentFunctionsAfterInlining , 1, 0) ///< Set when ///< -finstrument-functions-after-inlining is enabled. +CODEGENOPT(InstrumentFunctionEntryBare , 1, 0) ///< Set when + ///< -finstrument-function-entry-bare is enabled. CODEGENOPT(XRayInstrumentFunctions , 1, 0) ///< Set when -fxray-instrument is ///< enabled. diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index 8544da3..6b83591 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -355,10 +355,11 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { llvm::DebugLoc Loc = EmitReturnBlock(); if (ShouldInstrumentFunction()) { - CurFn->addFnAttr(!CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining - ? "instrument-function-exit" - : "instrument-function-exit-inlined", - "__cyg_profile_func_exit"); + if (CGM.getCodeGenOpts().InstrumentFunctions) + CurFn->addFnAttr("instrument-function-exit", "__cyg_profile_func_exit"); + if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) + CurFn->addFnAttr("instrument-function-exit-inlined", + "__cyg_profile_func_exit"); } // Emit debug descriptor for function end. @@ -443,7 +444,8 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { /// instrumented with __cyg_profile_func_* calls bool CodeGenFunction::ShouldInstrumentFunction() { if (!CGM.getCodeGenOpts().InstrumentFunctions && - !CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) + !CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining && + !CGM.getCodeGenOpts().InstrumentFunctionEntryBare) return false; if (!CurFuncDecl || CurFuncDecl->hasAttr()) return false; @@ -982,10 +984,14 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, } if (ShouldInstrumentFunction()) { - Fn->addFnAttr(!CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining - ? "instrument-function-entry" - : "instrument-function-entry-inlined", - "__cyg_profile_func_enter"); + if (CGM.getCodeGenOpts().InstrumentFunctions) + CurFn->addFnAttr("instrument-function-entry", "__cyg_profile_func_enter"); + if (CGM.getCodeGenOpts().InstrumentFunctionsAfterInlining) + CurFn->addFnAttr("instrument-function-entry-inlined", + "__cyg_profile_func_enter"); + if (CGM.getCodeGenOpts().InstrumentFunctionEntryBare) + CurFn->addFnAttr("instrument-function-entry-inlined", + "__cyg_profile_func_enter_bare"); } // Since emitting the mcount call here impacts optimizations such as function diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 2f1fa4a..3ab28d4 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -3554,8 +3554,11 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, options::OPT_fno_unique_section_names, true)) CmdArgs.push_back("-fno-unique-section-names"); - Args.AddLastArg(CmdArgs, options::OPT_finstrument_functions, - options::OPT_finstrument_functions_after_inlining); + if (auto *A = Args.getLastArg( + options::OPT_finstrument_functions, + options::OPT_finstrument_functions_after_inlining, + options::OPT_finstrument_function_entry_bare)) + A->render(Args, CmdArgs); addPGOAndCoverageFlags(C, D, Output, Args, CmdArgs); diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp index 384124b..3d48417 100644 --- a/clang/lib/Frontend/CompilerInvocation.cpp +++ b/clang/lib/Frontend/CompilerInvocation.cpp @@ -782,6 +782,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK, Opts.InstrumentFunctions = Args.hasArg(OPT_finstrument_functions); Opts.InstrumentFunctionsAfterInlining = Args.hasArg(OPT_finstrument_functions_after_inlining); + Opts.InstrumentFunctionEntryBare = + Args.hasArg(OPT_finstrument_function_entry_bare); Opts.XRayInstrumentFunctions = Args.hasArg(OPT_fxray_instrument); Opts.XRayInstructionThreshold = getLastArgIntValue(Args, OPT_fxray_instruction_threshold_EQ, 200, Diags); diff --git a/clang/test/CodeGen/instrument-functions.c b/clang/test/CodeGen/instrument-functions.c index b440e6a..c075c39 100644 --- a/clang/test/CodeGen/instrument-functions.c +++ b/clang/test/CodeGen/instrument-functions.c @@ -1,8 +1,12 @@ // RUN: %clang_cc1 -S -debug-info-kind=standalone -emit-llvm -o - %s -finstrument-functions -disable-llvm-passes | FileCheck %s +// RUN: %clang_cc1 -S -debug-info-kind=standalone -emit-llvm -o - %s -finstrument-function-entry-bare -disable-llvm-passes | FileCheck -check-prefix=BARE %s int test1(int x) { // CHECK: @test1(i32 {{.*}}%x) #[[ATTR1:[0-9]+]] // CHECK: ret + +// BARE: @test1(i32 {{.*}}%x) #[[ATTR1:[0-9]+]] +// BARE: ret return x; } @@ -10,6 +14,9 @@ int test2(int) __attribute__((no_instrument_function)); int test2(int x) { // CHECK: @test2(i32 {{.*}}%x) #[[ATTR2:[0-9]+]] // CHECK: ret + +// BARE: @test2(i32 {{.*}}%x) #[[ATTR2:[0-9]+]] +// BARE: ret return x; } @@ -17,5 +24,11 @@ int test2(int x) { // CHECK-SAME: "instrument-function-entry"="__cyg_profile_func_enter" // CHECK-SAME: "instrument-function-exit"="__cyg_profile_func_exit" +// BARE: attributes #[[ATTR1]] = +// BARE-SAME: "instrument-function-entry-inlined"="__cyg_profile_func_enter_bare" + // CHECK: attributes #[[ATTR2]] = // CHECK-NOT: "instrument-function-entry" + +// BARE: attributes #[[ATTR2]] = +// BARE-NOT: "instrument-function-entry" -- 2.7.4