The integrated darwin assembler can hang in an infinite loop (or get an assert

with a debug build) with this buggy .indirect_symbol directive usage:

% cat test.s
x: .indirect_symbol _y

The assertion is because it is trying to get the symbol index for the
symbol _y when it is writing out the indirect symbol table. This line of
code in MachObjectWriter::WriteObject() :

        Write32(Asm.getSymbolData(*it->Symbol).getIndex());

And while there is a symbol _y it does not have any getSymbolData set which
is only done in MachObjectWriter::BindIndirectSymbols() for pointer sections
or stub sections.  I added a check and an error in there to catch this in case
something slips through.

But to get a better error the parser should detect when a .indirect_symbol
directive is used and it is not in a pointer section or stub section.  To make
that work I moved the handling of the indirect symbol out of the target
independent AsmParser code into the DarwinAsmParser code that can check
for the proper Mach-O section types.

rdar://14825505

llvm-svn: 189497

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/lib/MC/MCParser/DarwinAsmParser.cpp b/llvm/lib/MC/MCParser/DarwinAsmParser.cpp
index 0aeeaf6cfaa..f08270c1528 100644
--- a/llvm/lib/MC/MCParser/DarwinAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/DarwinAsmParser.cpp
@@ -45,6 +45,8 @@ public:
     this->MCAsmParserExtension::Initialize(Parser);
 
     addDirectiveHandler<&DarwinAsmParser::ParseDirectiveDesc>(".desc");
+    addDirectiveHandler<&DarwinAsmParser::ParseDirectiveIndirectSymbol>(
+      ".indirect_symbol");
     addDirectiveHandler<&DarwinAsmParser::ParseDirectiveLsym>(".lsym");
     addDirectiveHandler<&DarwinAsmParser::ParseDirectiveSubsectionsViaSymbols>(
       ".subsections_via_symbols");
@@ -163,6 +165,7 @@ public:
   }
 
   bool ParseDirectiveDesc(StringRef, SMLoc);
+  bool ParseDirectiveIndirectSymbol(StringRef, SMLoc);
   bool ParseDirectiveDumpOrLoad(StringRef, SMLoc);
   bool ParseDirectiveLsym(StringRef, SMLoc);
   bool ParseDirectiveLinkerOption(StringRef, SMLoc);
@@ -415,6 +418,39 @@ bool DarwinAsmParser::ParseDirectiveDesc(StringRef, SMLoc) {
   return false;
 }
 
+/// ParseDirectiveIndirectSymbol
+///  ::= .indirect_symbol identifier
+bool DarwinAsmParser::ParseDirectiveIndirectSymbol(StringRef, SMLoc Loc) {
+  const MCSectionMachO *Current = static_cast<const MCSectionMachO*>(
+                                       getStreamer().getCurrentSection().first);
+  unsigned SectionType = Current->getType();
+  if (SectionType != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS &&
+      SectionType != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
+      SectionType != MCSectionMachO::S_SYMBOL_STUBS)
+    return Error(Loc, "indirect symbol not in a symbol pointer or stub "
+                      "section");
+
+  StringRef Name;
+  if (getParser().parseIdentifier(Name))
+    return TokError("expected identifier in .indirect_symbol directive");
+
+  MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
+
+  // Assembler local symbols don't make any sense here. Complain loudly.
+  if (Sym->isTemporary())
+    return TokError("non-local symbol required in directive");
+
+  if (!getStreamer().EmitSymbolAttribute(Sym, MCSA_IndirectSymbol))
+    return TokError("unable to emit indirect symbol attribute for: " + Name);
+
+  if (getLexer().isNot(AsmToken::EndOfStatement))
+    return TokError("unexpected token in '.indirect_symbol' directive");
+
+  Lex();
+
+  return false;
+}
+
 /// ParseDirectiveDumpOrLoad
 ///  ::= ( .dump | .load ) "filename"
 bool DarwinAsmParser::ParseDirectiveDumpOrLoad(StringRef Directive,