Expose -mllvm -accurate-sample-profile to clang.

Summary: With accurate sample profile, we can do more aggressive size optimization. For some size-critical application, this can reduce the text size by 20%

Reviewers: davidxl, rsmith

Reviewed By: davidxl, rsmith

Subscribers: mehdi_amini, eraman, sanjoy, cfe-commits

Differential Revision: https://reviews.llvm.org/D37091

llvm-svn: 311707

3 files changed, 10 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 17295ae2be8..a9a1a53be20 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -838,6 +838,10 @@ void CodeGenFunction::StartFunction(GlobalDecl GD,
   Fn->addFnAttr("no-jump-tables",
                 llvm::toStringRef(CGM.getCodeGenOpts().NoUseJumpTables));
 
+  // Add profile-sample-accurate value.
+  if (CGM.getCodeGenOpts().ProfileSampleAccurate)
+    Fn->addFnAttr("profile-sample-accurate");
+
   if (getLangOpts().OpenCL) {
     // Add metadata for a kernel function.
     if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(D))
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 35dcf206abb..fa768b70c53 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2340,6 +2340,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                     true))
     CmdArgs.push_back("-fno-jump-tables");
 
+  if (Args.hasFlag(options::OPT_fprofile_sample_accurate,
+                   options::OPT_fno_profile_sample_accurate, false))
+    CmdArgs.push_back("-fprofile-sample-accurate");
+
   if (!Args.hasFlag(options::OPT_fpreserve_as_comments,
                     options::OPT_fno_preserve_as_comments, true))
     CmdArgs.push_back("-fno-preserve-as-comments");
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 24a08e84dc4..aea3af98285 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -652,6 +652,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
 
   Opts.NoUseJumpTables = Args.hasArg(OPT_fno_jump_tables);
 
+  Opts.ProfileSampleAccurate = Args.hasArg(OPT_fprofile_sample_accurate);
+
   Opts.PrepareForLTO = Args.hasArg(OPT_flto, OPT_flto_EQ);
   Opts.EmitSummaryIndex = false;
   if (Arg *A = Args.getLastArg(OPT_flto_EQ)) {