[llvm] r189497 - The integrated darwin assembler can hang in an infinite loop (or get an assert
Kevin Enderby
enderby at apple.com
Wed Aug 28 10:50:59 PDT 2013
Author: enderby
Date: Wed Aug 28 12:50:59 2013
New Revision: 189497
URL: http://llvm.org/viewvc/llvm-project?rev=189497&view=rev
Log:
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
Added:
llvm/trunk/test/MC/MachO/bad-indirect-symbols.s
Modified:
llvm/trunk/lib/MC/MCParser/AsmParser.cpp
llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp
llvm/trunk/lib/MC/MachObjectWriter.cpp
Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=189497&r1=189496&r2=189497&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
+++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Wed Aug 28 12:50:59 2013
@@ -342,7 +342,7 @@ private:
DK_FLOAT, DK_DOUBLE, DK_ALIGN, DK_ALIGN32, DK_BALIGN, DK_BALIGNW,
DK_BALIGNL, DK_P2ALIGN, DK_P2ALIGNW, DK_P2ALIGNL, DK_ORG, DK_FILL, DK_ENDR,
DK_BUNDLE_ALIGN_MODE, DK_BUNDLE_LOCK, DK_BUNDLE_UNLOCK,
- DK_ZERO, DK_EXTERN, DK_GLOBL, DK_GLOBAL, DK_INDIRECT_SYMBOL,
+ DK_ZERO, DK_EXTERN, DK_GLOBL, DK_GLOBAL,
DK_LAZY_REFERENCE, DK_NO_DEAD_STRIP, DK_SYMBOL_RESOLVER, DK_PRIVATE_EXTERN,
DK_REFERENCE, DK_WEAK_DEFINITION, DK_WEAK_REFERENCE,
DK_WEAK_DEF_CAN_BE_HIDDEN, DK_COMM, DK_COMMON, DK_LCOMM, DK_ABORT,
@@ -1365,8 +1365,6 @@ bool AsmParser::ParseStatement(ParseStat
case DK_GLOBL:
case DK_GLOBAL:
return ParseDirectiveSymbolAttribute(MCSA_Global);
- case DK_INDIRECT_SYMBOL:
- return ParseDirectiveSymbolAttribute(MCSA_IndirectSymbol);
case DK_LAZY_REFERENCE:
return ParseDirectiveSymbolAttribute(MCSA_LazyReference);
case DK_NO_DEAD_STRIP:
@@ -3755,7 +3753,6 @@ void AsmParser::initializeDirectiveKindM
DirectiveKindMap[".extern"] = DK_EXTERN;
DirectiveKindMap[".globl"] = DK_GLOBL;
DirectiveKindMap[".global"] = DK_GLOBAL;
- DirectiveKindMap[".indirect_symbol"] = DK_INDIRECT_SYMBOL;
DirectiveKindMap[".lazy_reference"] = DK_LAZY_REFERENCE;
DirectiveKindMap[".no_dead_strip"] = DK_NO_DEAD_STRIP;
DirectiveKindMap[".symbol_resolver"] = DK_SYMBOL_RESOLVER;
Modified: llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp?rev=189497&r1=189496&r2=189497&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp (original)
+++ llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp Wed Aug 28 12:50:59 2013
@@ -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);
@@ -414,6 +417,39 @@ bool DarwinAsmParser::ParseDirectiveDesc
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"
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=189497&r1=189496&r2=189497&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Wed Aug 28 12:50:59 2013
@@ -428,6 +428,22 @@ void MachObjectWriter::BindIndirectSymbo
//
// FIXME: Revisit this when the dust settles.
+ // Report errors for use of .indirect_symbol not in a symbol pointer section
+ // or stub section.
+ for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
+ ie = Asm.indirect_symbol_end(); it != ie; ++it) {
+ const MCSectionMachO &Section =
+ cast<MCSectionMachO>(it->SectionData->getSection());
+
+ if (Section.getType() != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS &&
+ Section.getType() != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
+ Section.getType() != MCSectionMachO::S_SYMBOL_STUBS) {
+ MCSymbol &Symbol = *it->Symbol;
+ report_fatal_error("indirect symbol '" + Symbol.getName() +
+ "' not in a symbol pointer or stub section");
+ }
+ }
+
// Bind non lazy symbol pointers first.
unsigned IndirectIndex = 0;
for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
Added: llvm/trunk/test/MC/MachO/bad-indirect-symbols.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/bad-indirect-symbols.s?rev=189497&view=auto
==============================================================================
--- llvm/trunk/test/MC/MachO/bad-indirect-symbols.s (added)
+++ llvm/trunk/test/MC/MachO/bad-indirect-symbols.s Wed Aug 28 12:50:59 2013
@@ -0,0 +1,5 @@
+// RUN: not llvm-mc -triple x86_64-apple-darwin10 %s -filetype=obj -o - 2> %t.err > %t
+// RUN: FileCheck --check-prefix=CHECK-ERROR < %t.err %s
+
+x: .indirect_symbol _y
+// CHECK-ERROR: 4:4: error: indirect symbol not in a symbol pointer or stub section
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