[clang] fe177a1 - Fix assertion when passing function into inline asm's input operand

[Jason Liu via cfe-commits]

Author: Jason Liu
Date: 2021-08-27T13:39:41-04:00
New Revision: fe177a1773e4f88dde1aa37d34a0d3f8cb582f14

URL: https://github.com/llvm/llvm-project/commit/fe177a1773e4f88dde1aa37d34a0d3f8cb582f14
DIFF: https://github.com/llvm/llvm-project/commit/fe177a1773e4f88dde1aa37d34a0d3f8cb582f14.diff

LOG: Fix assertion when passing function into inline asm's input operand

This seem to be a regression caused by this change:
https://reviews.llvm.org/D60943.
Since we delayed report the error, we would run into some invalid
state in clang and llvm.

Without this fix, clang would assert when passing function into
inline asm's input operand.

Differential Revision: https://reviews.llvm.org/D107941

Added: 
    clang/test/CodeGen/asm-call-func.c

Modified: 
    clang/lib/Sema/SemaStmtAsm.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index 243d0b921cd7e..603611b2d86b1 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -393,30 +393,31 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                               diag::err_asm_invalid_lvalue_in_input)
                          << Info.getConstraintStr()
                          << InputExpr->getSourceRange());
-    } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
-      if (!InputExpr->isValueDependent()) {
-        Expr::EvalResult EVResult;
-        if (InputExpr->EvaluateAsRValue(EVResult, Context, true)) {
-          // 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))
-            if (!Info.isValidAsmImmediate(IntResult))
-              return StmtError(Diag(InputExpr->getBeginLoc(),
-                                    diag::err_invalid_asm_value_for_constraint)
-                               << toString(IntResult, 10)
-                               << Info.getConstraintStr()
-                               << InputExpr->getSourceRange());
-        }
-      }
-
     } else {
       ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
       if (Result.isInvalid())
         return StmtError();
 
-      Exprs[i] = Result.get();
+      InputExpr = Exprs[i] = Result.get();
+
+      if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
+        if (!InputExpr->isValueDependent()) {
+          Expr::EvalResult EVResult;
+          if (InputExpr->EvaluateAsRValue(EVResult, Context, true)) {
+            // 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))
+              if (!Info.isValidAsmImmediate(IntResult))
+                return StmtError(
+                    Diag(InputExpr->getBeginLoc(),
+                         diag::err_invalid_asm_value_for_constraint)
+                    << toString(IntResult, 10) << Info.getConstraintStr()
+                    << InputExpr->getSourceRange());
+          }
+        }
+      }
     }
 
     if (Info.allowsRegister()) {

diff  --git a/clang/test/CodeGen/asm-call-func.c b/clang/test/CodeGen/asm-call-func.c
new file mode 100644
index 0000000000000..851dcc093e76e
--- /dev/null
+++ b/clang/test/CodeGen/asm-call-func.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -emit-llvm %s -o - -triple x86_64-unknown-linux-gnu| FileCheck %s
+
+void callee(void);
+void caller() {
+  //CHECK: call void asm sideeffect "rcall $0", "n,~{dirflag},~{fpsr},~{flags}"(void ()* @callee)
+  asm("rcall %0" ::"n"(callee));
+}