[CodeView] Teach clang to emit the .debug$H COFF section.

Currently this is an LLVM extension to the COFF spec which is
experimental and intended to speed up linking.  For now it is
behind a hidden cl::opt flag, but in the future we can move it
to a "real" cc1 flag and have the driver pass it through whenever
it is appropriate.

The patch to actually make use of this section in lld will come
in a followup.

Differential Revision: https://reviews.llvm.org/D40917

llvm-svn: 320649

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCObjectFileInfo.cpp b/llvm/lib/MC/MCObjectFileInfo.cpp
index ba0146fd9fc..a6b5c43f1d2 100644
--- a/llvm/lib/MC/MCObjectFileInfo.cpp
+++ b/llvm/lib/MC/MCObjectFileInfo.cpp
@@ -185,6 +185,7 @@ void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
 
   COFFDebugSymbolsSection = nullptr;
   COFFDebugTypesSection = nullptr;
+  COFFGlobalTypeHashesSection = nullptr;
 
   if (useCompactUnwind(T)) {
     CompactUnwindSection =
@@ -655,6 +656,11 @@ void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
                                        COFF::IMAGE_SCN_MEM_READ),
                           SectionKind::getMetadata());
+  COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
+      ".debug$H",
+      (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
+       COFF::IMAGE_SCN_MEM_READ),
+      SectionKind::getMetadata());
 
   DwarfAbbrevSection = Ctx->getCOFFSection(
       ".debug_abbrev",