MachineModuleInfo: Don't allow dynamically setting DbgInfoAvailable

This can be set up front, and used only as a cache. This avoids a
field that looks like it requires MIR serialization.

I believe this fixes 2 bugs for CodeView. First, this addresses a
FIXME that the flag -diable-debug-info-print only works with
DWARF. Second, it fixes emitting debug info with emissionKind NoDebug.

1 files changed, 3 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index c0b7883..83d77cb 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -608,18 +608,16 @@ static SourceLanguage MapDWLangToCVLang(unsigned DWLang) {
 void CodeViewDebug::beginModule(Module *M) {
   // If module doesn't have named metadata anchors or COFF debug section
   // is not available, skip any debug info related stuff.
-  NamedMDNode *CUs = M->getNamedMetadata("llvm.dbg.cu");
-  if (!CUs || !Asm->getObjFileLowering().getCOFFDebugSymbolsSection()) {
+  if (!MMI->hasDebugInfo() ||
+      !Asm->getObjFileLowering().getCOFFDebugSymbolsSection()) {
     Asm = nullptr;
     return;
   }
-  // Tell MMI that we have and need debug info.
-  MMI->setDebugInfoAvailability(true);
 
   TheCPU = mapArchToCVCPUType(Triple(M->getTargetTriple()).getArch());
 
   // Get the current source language.
-  const MDNode *Node = *CUs->operands().begin();
+  const MDNode *Node = *M->debug_compile_units_begin();
   const auto *CU = cast<DICompileUnit>(Node);
 
   CurrentSourceLanguage = MapDWLangToCVLang(CU->getSourceLanguage());