Disable frame pointer elimination when using -pg

(Re-apply patch after bug fixing)

This diff makes sure that the driver does not pass
-fomit-frame-pointer or -momit-leaf-frame-pointer to
the frontend when -pg is used. Currently, clang gives 
an error if -fomit-frame-pointer is used in combination 
with -pg, but -momit-leaf-frame-pointer was forgotten.
Also, disable frame pointer elimination in the frontend 
when -pg is set.

Patch by Stefan Kempf.

llvm-svn: 253886

clang/lib/Driver/Tools.cpp

@@ -2794,6 +2794,8 @@ static bool shouldUseFramePointer(const ArgList &Args,
   if (Arg *A = Args.getLastArg(options::OPT_fno_omit_frame_pointer,
                                options::OPT_fomit_frame_pointer))
     return A->getOption().matches(options::OPT_fno_omit_frame_pointer);
+  if (Args.hasArg(options::OPT_pg))
+    return true;
 
   return shouldUseFramePointerForTarget(Args, Triple);
 }
@@ -2803,6 +2805,8 @@ static bool shouldUseLeafFramePointer(const ArgList &Args,
   if (Arg *A = Args.getLastArg(options::OPT_mno_omit_leaf_frame_pointer,
                                options::OPT_momit_leaf_frame_pointer))
     return A->getOption().matches(options::OPT_mno_omit_leaf_frame_pointer);
+  if (Args.hasArg(options::OPT_pg))
+    return true;
 
   if (Triple.isPS4CPU())
     return false;

clang/lib/Frontend/CompilerInvocation.cpp

@@ -453,7 +453,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
   Opts.CodeModel = getCodeModel(Args, Diags);
   Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
-  Opts.DisableFPElim = Args.hasArg(OPT_mdisable_fp_elim);
+  Opts.DisableFPElim =
+      (Args.hasArg(OPT_mdisable_fp_elim) || Args.hasArg(OPT_pg));
   Opts.DisableFree = Args.hasArg(OPT_disable_free);
   Opts.DisableTailCalls = Args.hasArg(OPT_mdisable_tail_calls);
   Opts.FloatABI = Args.getLastArgValue(OPT_mfloat_abi);

clang/test/CodeGen/x86_64-profiling-keep-fp.c

@@ -0,0 +1,14 @@
+// REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -O3 -pg -S -o - %s | \
+// RUN:   FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -O3 -momit-leaf-frame-pointer -pg -S -o - %s | \
+// RUN:   FileCheck %s
+
+// Test that the frame pointer is kept when compiling with
+// profiling.
+
+//CHECK: pushq %rbp
+int main(void)
+{
+  return 0;
+}