AsmParser/Writer: Handle symbolic constants in DI 'flags:'

Parse (and write) symbolic constants in debug info `flags:` fields.
This prevents a readability (and CHECK-ability) regression with the new
debug info hierarchy.

Old (well, current) assembly, with pretty-printing:

    !{!"...\\0016387", ...} ; ... [public] [rvalue reference]

Flags field without this change:

   !MDDerivedType(flags: 16387, ...)

Flags field with this change:

   !MDDerivedType(flags: DIFlagPublic | DIFlagRValueReference, ...)

As discussed in the review thread, this isn't a final state.  Most of
these flags correspond to `DW_AT_` symbolic constants, and we might
eventually want to support arbitrary attributes in some form.  However,
as it stands now, some of the flags correspond to other concepts (like
`FlagStaticMember`); until things are refactored this is the simplest
way to move forward without regressing assembly.

llvm-svn: 230111

3 files changed, 55 insertions, 5 deletions

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index 656b1692182..3bf090a4b33 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -241,6 +241,7 @@ lltok::Kind LLLexer::LexToken() {
   case ')': return lltok::rparen;
   case ',': return lltok::comma;
   case '*': return lltok::star;
+  case '|': return lltok::bar;
   }
 }
 
@@ -760,6 +761,11 @@ lltok::Kind LLLexer::LexIdentifier() {
   DWKEYWORD(OP, DwarfOp);
 #undef DWKEYWORD
 
+  if (Keyword.startswith("DIFlag")) {
+    StrVal.assign(Keyword.begin(), Keyword.end());
+    return lltok::DIFlag;
+  }
+
   // Check for [us]0x[0-9A-Fa-f]+ which are Hexadecimal constant generated by
   // the CFE to avoid forcing it to deal with 64-bit numbers.
   if ((TokStart[0] == 'u' || TokStart[0] == 's') &&
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 28b8d22e579..fa4653b30bc 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -16,6 +16,7 @@
 #include "llvm/IR/AutoUpgrade.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/InlineAsm.h"
@@ -2957,6 +2958,10 @@ struct DwarfLangField : public MDUnsignedField {
   DwarfLangField() : MDUnsignedField(0, dwarf::DW_LANG_hi_user) {}
 };
 
+struct DIFlagField : public MDUnsignedField {
+  DIFlagField() : MDUnsignedField(0, UINT32_MAX) {}
+};
+
 struct MDSignedField : public MDFieldImpl<int64_t> {
   int64_t Min;
   int64_t Max;
@@ -3086,6 +3091,43 @@ bool LLParser::ParseMDField(LocTy Loc, StringRef Name,
   return false;
 }
 
+/// DIFlagField
+///  ::= uint32
+///  ::= DIFlagVector
+///  ::= DIFlagVector '|' DIFlagFwdDecl '|' uint32 '|' DIFlagPublic
+template <>
+bool LLParser::ParseMDField(LocTy Loc, StringRef Name, DIFlagField &Result) {
+  assert(Result.Max == UINT32_MAX && "Expected only 32-bits");
+
+  // Parser for a single flag.
+  auto parseFlag = [&](unsigned &Val) {
+    if (Lex.getKind() == lltok::APSInt && !Lex.getAPSIntVal().isSigned())
+      return ParseUInt32(Val);
+
+    if (Lex.getKind() != lltok::DIFlag)
+      return TokError("expected debug info flag");
+
+    Val = DIDescriptor::getFlag(Lex.getStrVal());
+    if (!Val)
+      return TokError(Twine("invalid debug info flag flag '") +
+                      Lex.getStrVal() + "'");
+    Lex.Lex();
+    return false;
+  };
+
+  // Parse the flags and combine them together.
+  unsigned Combined = 0;
+  do {
+    unsigned Val;
+    if (parseFlag(Val))
+      return true;
+    Combined |= Val;
+  } while (EatIfPresent(lltok::bar));
+
+  Result.assign(Combined);
+  return false;
+}
+
 template <>
 bool LLParser::ParseMDField(LocTy Loc, StringRef Name,
                             MDSignedField &Result) {
@@ -3330,7 +3372,7 @@ bool LLParser::ParseMDDerivedType(MDNode *&Result, bool IsDistinct) {
   OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
   OPTIONAL(align, MDUnsignedField, (0, UINT64_MAX));                           \
   OPTIONAL(offset, MDUnsignedField, (0, UINT64_MAX));                          \
-  OPTIONAL(flags, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
   OPTIONAL(extraData, MDField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
@@ -3353,7 +3395,7 @@ bool LLParser::ParseMDCompositeType(MDNode *&Result, bool IsDistinct) {
   OPTIONAL(size, MDUnsignedField, (0, UINT64_MAX));                            \
   OPTIONAL(align, MDUnsignedField, (0, UINT64_MAX));                           \
   OPTIONAL(offset, MDUnsignedField, (0, UINT64_MAX));                          \
-  OPTIONAL(flags, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
   OPTIONAL(elements, MDField, );                                               \
   OPTIONAL(runtimeLang, DwarfLangField, );                                     \
   OPTIONAL(vtableHolder, MDField, );                                           \
@@ -3372,7 +3414,7 @@ bool LLParser::ParseMDCompositeType(MDNode *&Result, bool IsDistinct) {
 
 bool LLParser::ParseMDSubroutineType(MDNode *&Result, bool IsDistinct) {
 #define VISIT_MD_FIELDS(OPTIONAL, REQUIRED)                                    \
-  OPTIONAL(flags, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
   REQUIRED(types, MDField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
@@ -3449,7 +3491,7 @@ bool LLParser::ParseMDSubprogram(MDNode *&Result, bool IsDistinct) {
   OPTIONAL(containingType, MDField, );                                         \
   OPTIONAL(virtuality, DwarfVirtualityField, );                                \
   OPTIONAL(virtualIndex, MDUnsignedField, (0, UINT32_MAX));                    \
-  OPTIONAL(flags, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
   OPTIONAL(isOptimized, MDBoolField, );                                        \
   OPTIONAL(function, MDConstant, );                                            \
   OPTIONAL(templateParams, MDField, );                                         \
@@ -3585,7 +3627,7 @@ bool LLParser::ParseMDLocalVariable(MDNode *&Result, bool IsDistinct) {
   OPTIONAL(line, LineField, );                                                 \
   OPTIONAL(type, MDField, );                                                   \
   OPTIONAL(arg, MDUnsignedField, (0, UINT8_MAX));                              \
-  OPTIONAL(flags, MDUnsignedField, (0, UINT32_MAX));                           \
+  OPTIONAL(flags, DIFlagField, );                                              \
   OPTIONAL(inlinedAt, MDField, );
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index 57218dafbb9..a7aa17c37cc 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -29,6 +29,7 @@ namespace lltok {
     less, greater,     // <  >
     lparen, rparen,    // (  )
     exclaim,           // !
+    bar,               // |
 
     kw_x,
     kw_true,    kw_false,
@@ -203,6 +204,7 @@ namespace lltok {
     DwarfVirtuality,   // DW_VIRTUALITY_foo
     DwarfLang,         // DW_LANG_foo
     DwarfOp,           // DW_OP_foo
+    DIFlag,            // DIFlagFoo
 
     // Type valued tokens (TyVal).
     Type,