Sema: analyze I,J,K,M,N,O constraints

Add additional constraint checking for target specific behaviour for inline
assembly constraints.  We would previously silently let all arguments through
for these constraints.  In cases where the constraints were violated, we could
end up failing to select instructions and triggering assertions or worse,
silently ignoring instructions.

llvm-svn: 225244

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index afd785c5dfb..286c7619ed4 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -226,6 +226,20 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                               diag::err_asm_invalid_lvalue_in_input)
                          << Info.getConstraintStr()
                          << InputExpr->getSourceRange());
+    } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
+      llvm::APSInt Result;
+      if (!InputExpr->EvaluateAsInt(Result, Context))
+        return StmtError(
+            Diag(InputExpr->getLocStart(), diag::err_asm_invalid_type_in_input)
+            << InputExpr->getType() << Info.getConstraintStr()
+            << InputExpr->getSourceRange());
+      if (Result.slt(Info.getImmConstantMin()) ||
+          Result.sgt(Info.getImmConstantMax()))
+        return StmtError(Diag(InputExpr->getLocStart(),
+                              diag::err_invalid_asm_value_for_constraint)
+                         << Result.toString(10) << Info.getConstraintStr()
+                         << InputExpr->getSourceRange());
+
     } else {
       ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
       if (Result.isInvalid())