r217199 - Don't allow non-ASM statements in naked functions

[Hans Wennborg]

Author: hans
Date: Thu Sep  4 17:16:40 2014
New Revision: 217199

URL: http://llvm.org/viewvc/llvm-project?rev=217199&view=rev
Log:
Don't allow non-ASM statements in naked functions

Naked functions don't have prologues or epilogues, so doing
codegen for anything other than inline assembly would be completely
hit or miss.

Differential Revision: http://reviews.llvm.org/D5183

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/test/Sema/attr-naked.c

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=217199&r1=217198&r2=217199&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Sep  4 17:16:40 2014
@@ -6991,6 +6991,9 @@ def err_unknown_any_function : Error<
 def err_filter_expression_integral : Error<
   "filter expression type should be an integral value not %0">;
 
+def err_non_asm_stmt_in_naked_function : Error<
+  "non-ASM statement in naked function is not supported">;
+
 // OpenCL warnings and errors.
 def err_invalid_astype_of_different_size : Error<
   "invalid reinterpretation: sizes of %0 and %1 must match">;

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=217199&r1=217198&r2=217199&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Thu Sep  4 17:16:40 2014
@@ -10376,6 +10376,17 @@ Decl *Sema::ActOnFinishFunctionBody(Decl
          !CheckConstexprFunctionBody(FD, Body)))
       FD->setInvalidDecl();
 
+    if (FD && FD->hasAttr<NakedAttr>()) {
+      for (const Stmt *S : Body->children()) {
+        if (!isa<AsmStmt>(S)) {
+          Diag(S->getLocStart(), diag::err_non_asm_stmt_in_naked_function);
+          Diag(FD->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
+          FD->setInvalidDecl();
+          break;
+        }
+      }
+    }
+
     assert(ExprCleanupObjects.empty() && "Leftover temporaries in function");
     assert(!ExprNeedsCleanups && "Unaccounted cleanups in function");
     assert(MaybeODRUseExprs.empty() &&

Modified: cfe/trunk/test/Sema/attr-naked.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/attr-naked.c?rev=217199&r1=217198&r2=217199&view=diff
==============================================================================
--- cfe/trunk/test/Sema/attr-naked.c (original)
+++ cfe/trunk/test/Sema/attr-naked.c Thu Sep  4 17:16:40 2014
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -verify -fsyntax-only
+// RUN: %clang_cc1 %s -verify -fsyntax-only -triple i686-pc-linux
 
 int a __attribute__((naked)); // expected-warning {{'naked' attribute only applies to functions}}
 
@@ -10,3 +10,11 @@ void t1() __attribute__((naked));
 
 void t2() __attribute__((naked(2))); // expected-error {{'naked' attribute takes no arguments}}
 
+__attribute__((naked)) int t3() { // expected-note{{attribute is here}}
+  return 42; // expected-error{{non-ASM statement in naked function is not supported}}
+}
+
+__attribute__((naked)) int t4() {
+  asm("movl $42, %eax");
+  asm("retl");
+}