add scaffolding for target-specific MCExprs.

[oota-llvm.git] / lib / MC / MCExpr.cpp

diff --git a/lib/MC/MCExpr.cpp b/lib/MC/MCExpr.cpp
index 884211769a605acb40b8c9b60ec33a9b73ac60ac..07546c1b29b0e0c3dcf33f44cc4f296a071cec1e 100644 (file)
--- a/lib/MC/MCExpr.cpp
+++ b/lib/MC/MCExpr.cpp
@@ -11,18 +11,29 @@
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCValue.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
-void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
+void MCExpr::print(raw_ostream &OS) const {
   switch (getKind()) {
+  case MCExpr::Target:
+    return cast<MCTargetExpr>(this)->PrintImpl(OS);
   case MCExpr::Constant:
     OS << cast<MCConstantExpr>(*this).getValue();
     return;
 
-  case MCExpr::SymbolRef:
-    cast<MCSymbolRefExpr>(*this).getSymbol().print(OS, MAI);
+  case MCExpr::SymbolRef: {
+    const MCSymbol &Sym = cast<MCSymbolRefExpr>(*this).getSymbol();
+    
+    // Parenthesize names that start with $ so that they don't look like
+    // absolute names.
+    if (Sym.getName()[0] == '$')
+      OS << '(' << Sym << ')';
+    else
+      OS << Sym;
     return;
+  }
 
   case MCExpr::Unary: {
     const MCUnaryExpr &UE = cast<MCUnaryExpr>(*this);
@@ -33,18 +44,33 @@ void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
     case MCUnaryExpr::Not:   OS << '~'; break;
     case MCUnaryExpr::Plus:  OS << '+'; break;
     }
-    UE.getSubExpr()->print(OS, MAI);
+    OS << *UE.getSubExpr();
     return;
   }
 
   case MCExpr::Binary: {
     const MCBinaryExpr &BE = cast<MCBinaryExpr>(*this);
-    OS << '(';
-    BE.getLHS()->print(OS, MAI);
-    OS << ' ';
+    
+    // Only print parens around the LHS if it is non-trivial.
+    if (isa<MCConstantExpr>(BE.getLHS()) || isa<MCSymbolRefExpr>(BE.getLHS())) {
+      OS << *BE.getLHS();
+    } else {
+      OS << '(' << *BE.getLHS() << ')';
+    }
+    
     switch (BE.getOpcode()) {
     default: assert(0 && "Invalid opcode!");
-    case MCBinaryExpr::Add:  OS <<  '+'; break;
+    case MCBinaryExpr::Add:
+      // Print "X-42" instead of "X+-42".
+      if (const MCConstantExpr *RHSC = dyn_cast<MCConstantExpr>(BE.getRHS())) {
+        if (RHSC->getValue() < 0) {
+          OS << RHSC->getValue();
+          return;
+        }
+      }
+        
+      OS <<  '+';
+      break;
     case MCBinaryExpr::And:  OS <<  '&'; break;
     case MCBinaryExpr::Div:  OS <<  '/'; break;
     case MCBinaryExpr::EQ:   OS << "=="; break;
@@ -63,9 +89,13 @@ void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
     case MCBinaryExpr::Sub:  OS <<  '-'; break;
     case MCBinaryExpr::Xor:  OS <<  '^'; break;
     }
-    OS << ' ';
-    BE.getRHS()->print(OS, MAI);
-    OS << ')';
+    
+    // Only print parens around the LHS if it is non-trivial.
+    if (isa<MCConstantExpr>(BE.getRHS()) || isa<MCSymbolRefExpr>(BE.getRHS())) {
+      OS << *BE.getRHS();
+    } else {
+      OS << '(' << *BE.getRHS() << ')';
+    }
     return;
   }
   }
@@ -74,8 +104,8 @@ void MCExpr::print(raw_ostream &OS, const MCAsmInfo *MAI) const {
 }
 
 void MCExpr::dump() const {
-  print(errs(), 0);
-  errs() << '\n';
+  print(dbgs());
+  dbgs() << '\n';
 }
 
 /* *** */
@@ -99,12 +129,18 @@ const MCSymbolRefExpr *MCSymbolRefExpr::Create(const MCSymbol *Sym,
   return new (Ctx) MCSymbolRefExpr(Sym);
 }
 
+const MCSymbolRefExpr *MCSymbolRefExpr::Create(StringRef Name, MCContext &Ctx) {
+  return Create(Ctx.GetOrCreateSymbol(Name), Ctx);
+}
+
+MCTargetExpr::~MCTargetExpr() {}
+
 /* *** */
 
-bool MCExpr::EvaluateAsAbsolute(MCContext &Ctx, int64_t &Res) const {
+bool MCExpr::EvaluateAsAbsolute(int64_t &Res) const {
   MCValue Value;
   
-  if (!EvaluateAsRelocatable(Ctx, Value) || !Value.isAbsolute())
+  if (!EvaluateAsRelocatable(Value) || !Value.isAbsolute())
     return false;
 
   Res = Value.getConstant();
@@ -133,18 +169,23 @@ static bool EvaluateSymbolicAdd(const MCValue &LHS, const MCSymbol *RHS_A,
   return true;
 }
 
-bool MCExpr::EvaluateAsRelocatable(MCContext &Ctx, MCValue &Res) const {
+bool MCExpr::EvaluateAsRelocatable(MCValue &Res) const {
   switch (getKind()) {
+  case Target:
+    return cast<MCTargetExpr>(this)->EvaluateAsRelocatableImpl(Res);
+      
   case Constant:
     Res = MCValue::get(cast<MCConstantExpr>(this)->getValue());
     return true;
 
   case SymbolRef: {
     const MCSymbol &Sym = cast<MCSymbolRefExpr>(this)->getSymbol();
-    if (const MCValue *Value = Ctx.GetSymbolValue(&Sym))
-      Res = *Value;
-    else
-      Res = MCValue::get(&Sym, 0, 0);
+
+    // Evaluate recursively if this is a variable.
+    if (Sym.isVariable())
+      return Sym.getValue()->EvaluateAsRelocatable(Res);
+
+    Res = MCValue::get(&Sym, 0, 0);
     return true;
   }
 
@@ -152,7 +193,7 @@ bool MCExpr::EvaluateAsRelocatable(MCContext &Ctx, MCValue &Res) const {
     const MCUnaryExpr *AUE = cast<MCUnaryExpr>(this);
     MCValue Value;
 
-    if (!AUE->getSubExpr()->EvaluateAsRelocatable(Ctx, Value))
+    if (!AUE->getSubExpr()->EvaluateAsRelocatable(Value))
       return false;
 
     switch (AUE->getOpcode()) {
@@ -185,8 +226,8 @@ bool MCExpr::EvaluateAsRelocatable(MCContext &Ctx, MCValue &Res) const {
     const MCBinaryExpr *ABE = cast<MCBinaryExpr>(this);
     MCValue LHSValue, RHSValue;
     
-    if (!ABE->getLHS()->EvaluateAsRelocatable(Ctx, LHSValue) ||
-        !ABE->getRHS()->EvaluateAsRelocatable(Ctx, RHSValue))
+    if (!ABE->getLHS()->EvaluateAsRelocatable(LHSValue) ||
+        !ABE->getRHS()->EvaluateAsRelocatable(RHSValue))
       return false;
 
     // We only support a few operations on non-constant expressions, handle