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, 28 insertions, 2 deletions

diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 92cb53068dd..c156a60ffa7 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -3718,6 +3718,13 @@ struct EmissionKindField : public MDUnsignedField {
   EmissionKindField() : MDUnsignedField(0, DICompileUnit::LastEmissionKind) {}
 };
 
+struct NameTableKindField : public MDUnsignedField {
+  NameTableKindField()
+      : MDUnsignedField(
+            0, (unsigned)
+                   DICompileUnit::DebugNameTableKind::LastDebugNameTableKind) {}
+};
+
 struct DIFlagField : public MDFieldImpl<DINode::DIFlags> {
   DIFlagField() : MDFieldImpl(DINode::FlagZero) {}
 };
@@ -3938,6 +3945,25 @@ bool LLParser::ParseMDField(LocTy Loc, StringRef Name, EmissionKindField &Result
 
 template <>
 bool LLParser::ParseMDField(LocTy Loc, StringRef Name,
+                            NameTableKindField &Result) {
+  if (Lex.getKind() == lltok::APSInt)
+    return ParseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
+
+  if (Lex.getKind() != lltok::NameTableKind)
+    return TokError("expected nameTable kind");
+
+  auto Kind = DICompileUnit::getNameTableKind(Lex.getStrVal());
+  if (!Kind)
+    return TokError("invalid nameTable kind" + Twine(" '") + Lex.getStrVal() +
+                    "'");
+  assert(((unsigned)*Kind) <= Result.Max && "Expected valid nameTable kind");
+  Result.assign((unsigned)*Kind);
+  Lex.Lex();
+  return false;
+}
+
+template <>
+bool LLParser::ParseMDField(LocTy Loc, StringRef Name,
                             DwarfAttEncodingField &Result) {
   if (Lex.getKind() == lltok::APSInt)
     return ParseMDField(Loc, Name, static_cast<MDUnsignedField &>(Result));
@@ -4448,7 +4474,7 @@ bool LLParser::ParseDICompileUnit(MDNode *&Result, bool IsDistinct) {
   OPTIONAL(dwoId, MDUnsignedField, );                                          \
   OPTIONAL(splitDebugInlining, MDBoolField, = true);                           \
   OPTIONAL(debugInfoForProfiling, MDBoolField, = false);                       \
-  OPTIONAL(gnuPubnames, MDBoolField, = false);
+  OPTIONAL(nameTableKind, NameTableKindField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
 
@@ -4456,7 +4482,7 @@ bool LLParser::ParseDICompileUnit(MDNode *&Result, bool IsDistinct) {
       Context, language.Val, file.Val, producer.Val, isOptimized.Val, flags.Val,
       runtimeVersion.Val, splitDebugFilename.Val, emissionKind.Val, enums.Val,
       retainedTypes.Val, globals.Val, imports.Val, macros.Val, dwoId.Val,
-      splitDebugInlining.Val, debugInfoForProfiling.Val, gnuPubnames.Val);
+      splitDebugInlining.Val, debugInfoForProfiling.Val, nameTableKind.Val);
   return false;
 }