[CodeGen] prevent abnormal on invalid attributes

Currently, when an invalid attribute is encountered on processing a .s file,
clang will abort due to llvm_unreachable.  Invalid user input should not cause
an abnormal termination of the compiler.  Change the interface to return a
boolean to indicate the failure as a first step towards improving hanlding of
malformed user input to clang.

Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188047 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 36 insertions, 22 deletions

diff --git a/include/llvm/MC/MCELFStreamer.h b/include/llvm/MC/MCELFStreamer.h
index 7565c153f0..bff0cbad5b 100644
--- a/include/llvm/MC/MCELFStreamer.h
+++ b/include/llvm/MC/MCELFStreamer.h
@@ -57,7 +57,7 @@ public:
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
   virtual void EmitThumbFunc(MCSymbol *Func);
   virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
   virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
   virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                 unsigned ByteAlignment);
diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h
index 970c4ed99c..96b32cd358 100644
--- a/include/llvm/MC/MCStreamer.h
+++ b/include/llvm/MC/MCStreamer.h
@@ -323,7 +323,7 @@ namespace llvm {
     virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) = 0;
 
     /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
-    virtual void EmitSymbolAttribute(MCSymbol *Symbol,
+    virtual bool EmitSymbolAttribute(MCSymbol *Symbol,
                                      MCSymbolAttr Attribute) = 0;
 
     /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 781e40052b..60d72abbcb 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -154,7 +154,7 @@ public:
   virtual void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
                                          const MCSymbol *Label);
 
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
 
   virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
   virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);
@@ -436,7 +436,7 @@ void MCAsmStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
 }
 
 
-void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
+bool MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
                                         MCSymbolAttr Attribute) {
   switch (Attribute) {
   case MCSA_Invalid: llvm_unreachable("Invalid symbol attribute");
@@ -447,11 +447,12 @@ void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
   case MCSA_ELF_TypeCommon:      /// .type _foo, STT_COMMON  # aka @common
   case MCSA_ELF_TypeNoType:      /// .type _foo, STT_NOTYPE  # aka @notype
   case MCSA_ELF_TypeGnuUniqueObject:  /// .type _foo, @gnu_unique_object
-    assert(MAI->hasDotTypeDotSizeDirective() && "Symbol Attr not supported");
+    if (!MAI->hasDotTypeDotSizeDirective())
+      return false; // Symbol attribute not supported
     OS << "\t.type\t" << *Symbol << ','
        << ((MAI->getCommentString()[0] != '@') ? '@' : '%');
     switch (Attribute) {
-    default: llvm_unreachable("Unknown ELF .type");
+    default: return false;
     case MCSA_ELF_TypeFunction:    OS << "function"; break;
     case MCSA_ELF_TypeIndFunction: OS << "gnu_indirect_function"; break;
     case MCSA_ELF_TypeObject:      OS << "object"; break;
@@ -461,7 +462,7 @@ void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     case MCSA_ELF_TypeGnuUniqueObject: OS << "gnu_unique_object"; break;
     }
     EmitEOL();
-    return;
+    return true;
   case MCSA_Global: // .globl/.global
     OS << MAI->getGlobalDirective();
     FlagMap[Symbol] |= EHGlobal;
@@ -491,6 +492,8 @@ void MCAsmStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
 
   OS << *Symbol;
   EmitEOL();
+
+  return true;
 }
 
 void MCAsmStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 6e5ff50e37..4661d503c3 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -148,8 +148,8 @@ static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
   return T2;
 }
 
-void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
-                                          MCSymbolAttr Attribute) {
+bool MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
+                                        MCSymbolAttr Attribute) {
   // Indirect symbols are handled differently, to match how 'as' handles
   // them. This makes writing matching .o files easier.
   if (Attribute == MCSA_IndirectSymbol) {
@@ -159,7 +159,7 @@ void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     ISD.Symbol = Symbol;
     ISD.SectionData = getCurrentSectionData();
     getAssembler().getIndirectSymbols().push_back(ISD);
-    return;
+    return true;
   }
 
   // Adding a symbol attribute always introduces the symbol, note that an
@@ -182,7 +182,7 @@ void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
   case MCSA_WeakDefAutoPrivate:
   case MCSA_Invalid:
   case MCSA_IndirectSymbol:
-    llvm_unreachable("Invalid symbol attribute for ELF!");
+    return false;
 
   case MCSA_NoDeadStrip:
   case MCSA_ELF_TypeGnuUniqueObject:
@@ -251,6 +251,8 @@ void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
     break;
   }
+
+  return true;
 }
 
 void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 0729b7a2f2..bf8c561ea6 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -51,7 +51,7 @@ public:
   virtual void EmitLinkerOptions(ArrayRef<std::string> Options);
   virtual void EmitDataRegion(MCDataRegionType Kind);
   virtual void EmitThumbFunc(MCSymbol *Func);
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
   virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
   virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                 unsigned ByteAlignment);
@@ -217,7 +217,7 @@ void MCMachOStreamer::EmitThumbFunc(MCSymbol *Symbol) {
   SD.setFlags(SD.getFlags() | SF_ThumbFunc);
 }
 
-void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
+bool MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
                                           MCSymbolAttr Attribute) {
   // Indirect symbols are handled differently, to match how 'as' handles
   // them. This makes writing matching .o files easier.
@@ -228,7 +228,7 @@ void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     ISD.Symbol = Symbol;
     ISD.SectionData = getCurrentSectionData();
     getAssembler().getIndirectSymbols().push_back(ISD);
-    return;
+    return true;
   }
 
   // Adding a symbol attribute always introduces the symbol, note that an
@@ -257,7 +257,7 @@ void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
   case MCSA_Protected:
   case MCSA_Weak:
   case MCSA_Local:
-    llvm_unreachable("Invalid symbol attribute for Mach-O!");
+    return false;
 
   case MCSA_Global:
     SD.setExternal(true);
@@ -309,6 +309,8 @@ void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     SD.setFlags(SD.getFlags() | SF_WeakDefinition | SF_WeakReference);
     break;
   }
+
+  return true;
 }
 
 void MCMachOStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 530c6469e0..87a7db69cd 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -52,7 +52,9 @@ namespace {
                                           const MCSymbol *Label,
                                           unsigned PointerSize) {}
 
-    virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){}
+    virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute){
+      return true;
+    }
 
     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
 
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index dd0d181b6f..07796dd6b0 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -3375,7 +3375,8 @@ bool AsmParser::ParseDirectiveSymbolAttribute(MCSymbolAttr Attr) {
       if (Sym->isTemporary())
         return Error(Loc, "non-local symbol required in directive");
 
-      getStreamer().EmitSymbolAttribute(Sym, Attr);
+      if (!getStreamer().EmitSymbolAttribute(Sym, Attr))
+        return Error(Loc, "unable to emit symbol attribute");
 
       if (getLexer().is(AsmToken::EndOfStatement))
         break;
diff --git a/lib/MC/MCPureStreamer.cpp b/lib/MC/MCPureStreamer.cpp
index c5c3bb7055..c6c772c6e2 100644
--- a/lib/MC/MCPureStreamer.cpp
+++ b/lib/MC/MCPureStreamer.cpp
@@ -51,8 +51,9 @@ public:
   virtual void FinishImpl();
 
 
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
     report_fatal_error("unsupported directive in pure streamer");
+    return false;
   }
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) {
     report_fatal_error("unsupported directive in pure streamer");
diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index 04bfeb4c2b..3f0449dc46 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -55,7 +55,7 @@ public:
   virtual void EmitDebugLabel(MCSymbol *Symbol);
   virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
   virtual void EmitThumbFunc(MCSymbol *Func);
-  virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
   virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
   virtual void BeginCOFFSymbolDef(MCSymbol const *Symbol);
   virtual void EmitCOFFSymbolStorageClass(int StorageClass);
@@ -201,7 +201,7 @@ void WinCOFFStreamer::EmitThumbFunc(MCSymbol *Func) {
   llvm_unreachable("not implemented");
 }
 
-void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
+bool WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
                                           MCSymbolAttr Attribute) {
   assert(Symbol && "Symbol must be non-null!");
   assert((Symbol->isInSection()
@@ -221,8 +221,10 @@ void WinCOFFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
     break;
 
   default:
-    llvm_unreachable("unsupported attribute");
+    return false;
   }
+
+  return true;
 }
 
 void WinCOFFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
diff --git a/tools/lto/LTOModule.cpp b/tools/lto/LTOModule.cpp
index e89733f587..1812346077 100644
--- a/tools/lto/LTOModule.cpp
+++ b/tools/lto/LTOModule.cpp
@@ -738,9 +738,10 @@ namespace {
       // FIXME: should we handle aliases?
       markDefined(*Symbol);
     }
-    virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
+    virtual bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) {
       if (Attribute == MCSA_Global)
         markGlobal(*Symbol);
+      return true;
     }
     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
                               uint64_t Size , unsigned ByteAlignment) {