Inline asm constraints: allow ICE-like pointers for the "n" constraint (PR40890)
Apparently GCC allows this, and there's code relying on it (see bug).
The idea is to allow expression that would have been allowed if they
were cast to int. So I based the code on how such a cast would be done
(the CK_PointerToIntegral case in IntExprEvaluator::VisitCastExpr()).
Differential Revision: https://reviews.llvm.org/D58821
llvm-svn: 355491
diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index 0d38f48..8c60125 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -385,11 +385,20 @@
return StmtError(
Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
<< Info.getConstraintStr() << InputExpr->getSourceRange());
- llvm::APSInt Result = EVResult.Val.getInt();
- if (!Info.isValidAsmImmediate(Result))
+
+ // For compatibility with GCC, we also allow pointers that would be
+ // integral constant expressions if they were cast to int.
+ llvm::APSInt IntResult;
+ if (!EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
+ Context))
+ return StmtError(
+ Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
+ << Info.getConstraintStr() << InputExpr->getSourceRange());
+
+ if (!Info.isValidAsmImmediate(IntResult))
return StmtError(Diag(InputExpr->getBeginLoc(),
diag::err_invalid_asm_value_for_constraint)
- << Result.toString(10) << Info.getConstraintStr()
+ << IntResult.toString(10) << Info.getConstraintStr()
<< InputExpr->getSourceRange());
}