If an input constraint refers to an output constraint, it should have the same constraint info as the output constraint. Fixes PR3417

llvm-svn: 63127

clang/include/clang/Basic/TargetInfo.h

@@ -201,6 +201,7 @@ public:
   bool validateInputConstraint(const char *Name, 
                                const std::string *OutputNamesBegin,
                                const std::string *OutputNamesEnd,
+                               ConstraintInfo* OutputConstraints,
                                ConstraintInfo &info) const;
   bool resolveSymbolicName(const char *&Name,
                            const std::string *OutputNamesBegin,

clang/lib/Basic/TargetInfo.cpp

@@ -222,6 +222,7 @@ bool TargetInfo::resolveSymbolicName(const char *&Name,
 bool TargetInfo::validateInputConstraint(const char *Name,
                                          const std::string *OutputNamesBegin,
                                          const std::string *OutputNamesEnd,
+                                         ConstraintInfo* OutputConstraints,
                                          ConstraintInfo &info) const {
   info = CI_None;
 
@@ -236,6 +237,10 @@ bool TargetInfo::validateInputConstraint(const char *Name,
         // Check if matching constraint is out of bounds.
         if (i >= NumOutputs)
           return false;
+        
+        // The constraint should have the same info as the respective 
+        // output constraint.
+        info = (ConstraintInfo)(info|OutputConstraints[i]);
       } else if (!validateAsmConstraint(*Name, info)) {
         // FIXME: This error return is in place temporarily so we can
         // add more constraints as we hit it.  Eventually, an unknown

clang/lib/CodeGen/CGStmt.cpp

@@ -933,6 +933,8 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
   std::vector<llvm::Value*> InOutArgs;
   std::vector<const llvm::Type*> InOutArgTypes;
 
+  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());
@@ -942,6 +944,8 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
                                                   Info);
     assert(result && "Failed to parse output constraint"); result=result;
     
+    OutputConstraintInfos.push_back(Info);
+
     // Simplify the output constraint.
     OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1, Target);
     
@@ -993,6 +997,7 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
     bool result = Target.validateInputConstraint(InputConstraint.c_str(),
                                                  S.begin_output_names(),
                                                  S.end_output_names(),
+                                                 &OutputConstraintInfos[0],
                                                  Info); result=result;
     assert(result && "Failed to parse input constraint");
     

clang/lib/Sema/SemaStmt.cpp

@@ -849,6 +849,8 @@ Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
   StringLiteral *AsmString = cast<StringLiteral>((Expr *)asmString.get());
   StringLiteral **Clobbers = reinterpret_cast<StringLiteral**>(clobbers.get());
 
+  llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
+  
   // The parser verifies that there is a string literal here.
   if (AsmString->isWide())
     return StmtError(Diag(AsmString->getLocStart(),diag::err_asm_wide_character)
@@ -877,6 +879,8 @@ Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
                   diag::err_asm_invalid_lvalue_in_output)
         << OutputExpr->getSubExpr()->getSourceRange());
     }
+    
+    OutputConstraintInfos.push_back(info);
   }
 
   for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
@@ -891,7 +895,9 @@ Sema::OwningStmtResult Sema::ActOnAsmStmt(SourceLocation AsmLoc,
     TargetInfo::ConstraintInfo info;
     if (!Context.Target.validateInputConstraint(InputConstraint.c_str(),
                                                 &Names[0],
-                                                &Names[0] + NumOutputs, info)) {
+                                                &Names[0] + NumOutputs, 
+                                                &OutputConstraintInfos[0],
+                                                info)) {
       return StmtError(Diag(Literal->getLocStart(),
                   diag::err_asm_invalid_input_constraint) << InputConstraint);
     }

clang/test/CodeGen/asm.c

@@ -22,7 +22,8 @@ void t4()
 	__asm__ volatile ("":: "m"(a), "m"(b));
 }
 
-
-
-
-
+// PR3417
+void t5(int i)
+{
+  asm("nop" : "=r"(i) : "0"(t5));
+}