Convert assert(0) to llvm_unreachable

[oota-llvm.git] / lib / MC / MCParser / AsmParser.cpp

diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 1af7cd9ee0d9694972ffd29bb8f494e503bf184b..bd5956f9b482d8531d11140850440c09878f99c4 100644 (file)
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -30,6 +30,7 @@
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCTargetAsmParser.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/SourceMgr.h"
@@ -122,6 +123,9 @@ private:
   int64_t CppHashLineNumber;
   SMLoc CppHashLoc;
 
+  /// AssemblerDialect. ~OU means unset value and use value provided by MAI.
+  unsigned AssemblerDialect;
+
 public:
   AsmParser(SourceMgr &SM, MCContext &Ctx, MCStreamer &Out,
             const MCAsmInfo &MAI);
@@ -143,7 +147,15 @@ public:
   virtual MCAsmLexer &getLexer() { return Lexer; }
   virtual MCContext &getContext() { return Ctx; }
   virtual MCStreamer &getStreamer() { return Out; }
-  virtual unsigned getAssemblerDialect() { return MAI.getAssemblerDialect(); }
+  virtual unsigned getAssemblerDialect() { 
+    if (AssemblerDialect == ~0U)
+      return MAI.getAssemblerDialect(); 
+    else
+      return AssemblerDialect;
+  }
+  virtual void setAssemblerDialect(unsigned i) {
+    AssemblerDialect = i;
+  }
 
   virtual bool Warning(SMLoc L, const Twine &Msg,
                        ArrayRef<SMRange> Ranges = ArrayRef<SMRange>());
@@ -368,7 +380,8 @@ AsmParser::AsmParser(SourceMgr &_SM, MCContext &_Ctx,
                      MCStreamer &_Out, const MCAsmInfo &_MAI)
   : Lexer(_MAI), Ctx(_Ctx), Out(_Out), MAI(_MAI), SrcMgr(_SM),
     GenericParser(new GenericAsmParser), PlatformParser(0),
-    CurBuffer(0), MacrosEnabled(true), CppHashLineNumber(0) {
+    CurBuffer(0), MacrosEnabled(true), CppHashLineNumber(0), 
+    AssemblerDialect(~0U) {
   // Save the old handler.
   SavedDiagHandler = SrcMgr.getDiagHandler();
   SavedDiagContext = SrcMgr.getDiagContext();
@@ -792,8 +805,7 @@ AsmParser::ApplyModifierToExpr(const MCExpr *E,
   }
   }
 
-  assert(0 && "Invalid expression kind!");
-  return 0;
+  llvm_unreachable("Invalid expression kind!");
 }
 
 /// ParseExpression - Parse an expression and return it.
@@ -1553,23 +1565,27 @@ void AsmParser::HandleMacroExit() {
   ActiveMacros.pop_back();
 }
 
-static void MarkUsed(const MCExpr *Value) {
+static bool IsUsedIn(const MCSymbol *Sym, const MCExpr *Value) {
   switch (Value->getKind()) {
-  case MCExpr::Binary:
-    MarkUsed(static_cast<const MCBinaryExpr*>(Value)->getLHS());
-    MarkUsed(static_cast<const MCBinaryExpr*>(Value)->getRHS());
+  case MCExpr::Binary: {
+    const MCBinaryExpr *BE = static_cast<const MCBinaryExpr*>(Value);
+    return IsUsedIn(Sym, BE->getLHS()) || IsUsedIn(Sym, BE->getRHS());
     break;
+  }
   case MCExpr::Target:
   case MCExpr::Constant:
-    break;
+    return false;
   case MCExpr::SymbolRef: {
-    static_cast<const MCSymbolRefExpr*>(Value)->getSymbol().setUsed(true);
-    break;
+    const MCSymbol &S = static_cast<const MCSymbolRefExpr*>(Value)->getSymbol();
+    if (S.isVariable())
+      return IsUsedIn(Sym, S.getVariableValue());
+    return &S == Sym;
   }
   case MCExpr::Unary:
-    MarkUsed(static_cast<const MCUnaryExpr*>(Value)->getSubExpr());
-    break;
+    return IsUsedIn(Sym, static_cast<const MCUnaryExpr*>(Value)->getSubExpr());
   }
+
+  llvm_unreachable("Unknown expr kind!");
 }
 
 bool AsmParser::ParseAssignment(StringRef Name, bool allow_redef) {
@@ -1580,7 +1596,9 @@ bool AsmParser::ParseAssignment(StringRef Name, bool allow_redef) {
   if (ParseExpression(Value))
     return true;
 
-  MarkUsed(Value);
+  // Note: we don't count b as used in "a = b". This is to allow
+  // a = b
+  // b = c
 
   if (Lexer.isNot(AsmToken::EndOfStatement))
     return TokError("unexpected token in assignment");
@@ -1602,7 +1620,9 @@ bool AsmParser::ParseAssignment(StringRef Name, bool allow_redef) {
     //
     // FIXME: Diagnostics. Note the location of the definition as a label.
     // FIXME: Diagnose assignment to protected identifier (e.g., register name).
-    if (Sym->isUndefined() && !Sym->isUsed() && !Sym->isVariable())
+    if (IsUsedIn(Sym, Value))
+      return Error(EqualLoc, "Recursive use of '" + Name + "'");
+    else if (Sym->isUndefined() && !Sym->isUsed() && !Sym->isVariable())
       ; // Allow redefinitions of undefined symbols only used in directives.
     else if (!Sym->isUndefined() && (!Sym->isVariable() || !allow_redef))
       return Error(EqualLoc, "redefinition of '" + Name + "'");