add some helper methods to AsmStmt and add some comments.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@66521 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 60 insertions, 22 deletions

diff --git a/include/clang/AST/Stmt.h b/include/clang/AST/Stmt.h
index 465b26ff23..40420ddc4b 100644
--- a/include/clang/AST/Stmt.h
+++ b/include/clang/AST/Stmt.h
@@ -923,36 +923,65 @@ public:
   bool isVolatile() const { return IsVolatile; }
   bool isSimple() const { return IsSimple; }
 
+  //===--- Output operands ---===//
+
   unsigned getNumOutputs() const { return NumOutputs; }
 
   const std::string &getOutputName(unsigned i) const {
     return Names[i];
   }
 
-  const StringLiteral *getOutputConstraint(unsigned i) const {
+  /// getOutputConstraint - Return the constraint string for the specified
+  /// output operand.  All output constraints are known to be non-empty (either
+  /// '=' or '+').
+  std::string getOutputConstraint(unsigned i) const;
+  
+  const StringLiteral *getOutputConstraintLiteral(unsigned i) const {
     return Constraints[i];
   }
-
-  StringLiteral *getOutputConstraint(unsigned i)
-    { return Constraints[i]; }
-
-  const Expr *getOutputExpr(unsigned i) const;
+  StringLiteral *getOutputConstraintLiteral(unsigned i) {
+    return Constraints[i];
+  }
+  
+  
   Expr *getOutputExpr(unsigned i);
   
+  const Expr *getOutputExpr(unsigned i) const {
+    return const_cast<AsmStmt*>(this)->getOutputExpr(i);
+  }
+  
+  /// isOutputPlusConstraint - Return true if the specified output constraint
+  /// is a "+" constraint (which is both an input and an output) or false if it
+  /// is an "=" constraint (just an output).
+  bool isOutputPlusConstraint(unsigned i) const {
+    return getOutputConstraint(i)[0] == '+';
+  }
+  
+  //===--- Input operands ---===//
+  
   unsigned getNumInputs() const { return NumInputs; }  
   
   const std::string &getInputName(unsigned i) const {
     return Names[i + NumOutputs];
   }
-  StringLiteral *getInputConstraint(unsigned i) {
+  
+  /// getInputConstraint - Return the specified input constraint.  Unlike output
+  /// constraints, these can be empty.
+  std::string getInputConstraint(unsigned i) const;
+  
+  const StringLiteral *getInputConstraintLiteral(unsigned i) const {
     return Constraints[i + NumOutputs];
   }
-  const StringLiteral *getInputConstraint(unsigned i) const {
+  StringLiteral *getInputConstraintLiteral(unsigned i) {
     return Constraints[i + NumOutputs];
   }
-
+  
+  
   Expr *getInputExpr(unsigned i);
-  const Expr *getInputExpr(unsigned i) const;
+  
+  const Expr *getInputExpr(unsigned i) const {
+    return const_cast<AsmStmt*>(this)->getInputExpr(i);
+  }
 
   const StringLiteral *getAsmString() const { return AsmStr; }
   StringLiteral *getAsmString() { return AsmStr; }
diff --git a/lib/AST/Stmt.cpp b/lib/AST/Stmt.cpp
index 749b677d91..682a9b1ee4 100644
--- a/lib/AST/Stmt.cpp
+++ b/lib/AST/Stmt.cpp
@@ -130,17 +130,28 @@ bool Stmt::hasImplicitControlFlow() const {
   }
 }
 
-const Expr* AsmStmt::getOutputExpr(unsigned i) const {
+Expr *AsmStmt::getOutputExpr(unsigned i) {
   return cast<Expr>(Exprs[i]);
 }
-Expr* AsmStmt::getOutputExpr(unsigned i) {
-  return cast<Expr>(Exprs[i]);
+
+/// getOutputConstraint - Return the constraint string for the specified
+/// output operand.  All output constraints are known to be non-empty (either
+/// '=' or '+').
+std::string AsmStmt::getOutputConstraint(unsigned i) const {
+  return std::string(Constraints[i]->getStrData(),
+                     Constraints[i]->getByteLength());
 }
-Expr* AsmStmt::getInputExpr(unsigned i) {
+
+
+Expr *AsmStmt::getInputExpr(unsigned i) {
   return cast<Expr>(Exprs[i + NumOutputs]);
 }
-const Expr* AsmStmt::getInputExpr(unsigned i) const {
-  return cast<Expr>(Exprs[i + NumOutputs]);
+
+/// getInputConstraint - Return the specified input constraint.  Unlike output
+/// constraints, these can be empty.
+std::string AsmStmt::getInputConstraint(unsigned i) const {
+  return std::string(Constraints[i + NumOutputs]->getStrData(),
+                     Constraints[i + NumOutputs]->getByteLength());
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index e6ac310b83..bcd1a86ca6 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -397,7 +397,7 @@ void StmtPrinter::VisitAsmStmt(AsmStmt *Node) {
       OS << "] ";
     }
     
-    VisitStringLiteral(Node->getOutputConstraint(i));
+    VisitStringLiteral(Node->getOutputConstraintLiteral(i));
     OS << " ";
     Visit(Node->getOutputExpr(i));
   }
@@ -416,7 +416,7 @@ void StmtPrinter::VisitAsmStmt(AsmStmt *Node) {
       OS << "] ";
     }
     
-    VisitStringLiteral(Node->getInputConstraint(i));
+    VisitStringLiteral(Node->getInputConstraintLiteral(i));
     OS << " ";
     Visit(Node->getInputExpr(i));
   }
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 69ed0803c3..3fd6526777 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -919,8 +919,7 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
   llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
 
   for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) {    
-    std::string OutputConstraint(S.getOutputConstraint(i)->getStrData(),
-                                 S.getOutputConstraint(i)->getByteLength());
+    std::string OutputConstraint(S.getOutputConstraint(i));
     
     TargetInfo::ConstraintInfo Info;
     bool result = Target.validateOutputConstraint(OutputConstraint.c_str(), 
@@ -973,8 +972,7 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
   for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) {
     const Expr *InputExpr = S.getInputExpr(i);
 
-    std::string InputConstraint(S.getInputConstraint(i)->getStrData(),
-                                S.getInputConstraint(i)->getByteLength());
+    std::string InputConstraint(S.getInputConstraint(i));
     
     TargetInfo::ConstraintInfo Info;
     bool result = Target.validateInputConstraint(InputConstraint.c_str(),