[codeview] Expose -gcodeview-ghash for global type hashing
Summary:
Experience has shown that the functionality is useful. It makes linking
optimized clang with debug info for me a lot faster, 20s to 13s. The
type merging phase of PDB writing goes from 10s to 3s.
This removes the LLVM cl::opt and replaces it with a metadata flag.
After this change, users can do the following to use ghash:
- add -gcodeview-ghash to compiler flags
- replace /DEBUG with /DEBUG:GHASH in linker flags
Reviewers: zturner, hans, thakis, takuto.ikuta
Subscribers: aprantl, hiraditya, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D54370
llvm-svn: 347072
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 01d018f..3b1fd76 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -92,9 +92,6 @@
using namespace llvm;
using namespace llvm::codeview;
-static cl::opt<bool> EmitDebugGlobalHashes("emit-codeview-ghash-section",
- cl::ReallyHidden, cl::init(false));
-
static CPUType mapArchToCVCPUType(Triple::ArchType Type) {
switch (Type) {
case Triple::ArchType::x86:
@@ -125,6 +122,11 @@
TheCPU =
mapArchToCVCPUType(Triple(MMI->getModule()->getTargetTriple()).getArch());
+
+ // Check if we should emit type record hashes.
+ ConstantInt *GH = mdconst::extract_or_null<ConstantInt>(
+ MMI->getModule()->getModuleFlag("CodeViewGHash"));
+ EmitDebugGlobalHashes = GH && !GH->isZero();
}
StringRef CodeViewDebug::getFullFilepath(const DIFile *File) {