Uniuqe Names for Internal Linkage Symbols.

This is a standalone patch and this would help Propeller do a better job of code
layout as it can accurately attribute the profiles to the right internal linkage
function.

This also helps SampledFDO/AutoFDO correctly associate sampled profiles to the
right internal function. Currently, if there is more than one internal symbol
foo, their profiles are aggregated by SampledFDO.

This patch adds a new clang option, -funique-internal-funcnames, to generate
unique names for functions with internal linkage. This patch appends the md5
hash of the module name to the function symbol as a best effort to generate a
unique name for symbols with internal linkage.

Differential Revision: https://reviews.llvm.org/D73307

1 files changed, 2 insertions, 0 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 18872f9..01f0673 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -957,6 +957,8 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DataSections = Args.hasArg(OPT_fdata_sections);
   Opts.StackSizeSection = Args.hasArg(OPT_fstack_size_section);
   Opts.UniqueSectionNames = !Args.hasArg(OPT_fno_unique_section_names);
+  Opts.UniqueInternalLinkageNames =
+      Args.hasArg(OPT_funique_internal_linkage_names);
 
   Opts.MergeFunctions = Args.hasArg(OPT_fmerge_functions);