DebugInfo: Add metadata support for disabling DWARF pub sections

In cases where the debugger load time is a worthwhile tradeoff (or less
costly - such as loading from a DWP instead of a variety of DWOs
(possibly over a high-latency/distributed filesystem)) against object
file size, it can be reasonable to disable pubnames and corresponding
gdb-index creation in the linker.

A backend-flag version of this was implemented for NVPTX in
D44385/r327994 - which was fine for NVPTX which wouldn't mix-and-match
CUs. Now that it's going to be a user-facing option (likely powered by
"-gno-pubnames", the same as GCC) it should be encoded in the
DICompileUnit so it can vary per-CU.

After this, likely the NVPTX support should be migrated to the metadata
& the previous flag implementation should be removed.

Reviewers: aprantl

Differential Revision: https://reviews.llvm.org/D50213

llvm-svn: 339939

1 files changed, 23 insertions, 2 deletions

diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index ddd226f1d5d..242d92582c2 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -450,7 +450,7 @@ DICompileUnit *DICompileUnit::getImpl(
     unsigned EmissionKind, Metadata *EnumTypes, Metadata *RetainedTypes,
     Metadata *GlobalVariables, Metadata *ImportedEntities, Metadata *Macros,
     uint64_t DWOId, bool SplitDebugInlining, bool DebugInfoForProfiling,
-    bool GnuPubnames, StorageType Storage, bool ShouldCreate) {
+    unsigned NameTableKind, StorageType Storage, bool ShouldCreate) {
   assert(Storage != Uniqued && "Cannot unique DICompileUnit");
   assert(isCanonical(Producer) && "Expected canonical MDString");
   assert(isCanonical(Flags) && "Expected canonical MDString");
@@ -463,7 +463,7 @@ DICompileUnit *DICompileUnit::getImpl(
   return storeImpl(new (array_lengthof(Ops)) DICompileUnit(
                        Context, Storage, SourceLanguage, IsOptimized,
                        RuntimeVersion, EmissionKind, DWOId, SplitDebugInlining,
-                       DebugInfoForProfiling, GnuPubnames, Ops),
+                       DebugInfoForProfiling, NameTableKind, Ops),
                    Storage);
 }
 
@@ -477,6 +477,15 @@ DICompileUnit::getEmissionKind(StringRef Str) {
       .Default(None);
 }
 
+Optional<DICompileUnit::DebugNameTableKind>
+DICompileUnit::getNameTableKind(StringRef Str) {
+  return StringSwitch<Optional<DebugNameTableKind>>(Str)
+      .Case("Default", DebugNameTableKind::Default)
+      .Case("GNU", DebugNameTableKind::GNU)
+      .Case("None", DebugNameTableKind::None)
+      .Default(None);
+}
+
 const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
   switch (EK) {
   case NoDebug:        return "NoDebug";
@@ -487,6 +496,18 @@ const char *DICompileUnit::emissionKindString(DebugEmissionKind EK) {
   return nullptr;
 }
 
+const char *DICompileUnit::nameTableKindString(DebugNameTableKind NTK) {
+  switch (NTK) {
+  case DebugNameTableKind::Default:
+    return nullptr;
+  case DebugNameTableKind::GNU:
+    return "GNU";
+  case DebugNameTableKind::None:
+    return "None";
+  }
+  return nullptr;
+}
+
 DISubprogram *DILocalScope::getSubprogram() const {
   if (auto *Block = dyn_cast<DILexicalBlockBase>(this))
     return Block->getScope()->getSubprogram();