From: Hans Wennborg <hans@hanshq.net>
Date: Thu, 4 Sep 2014 22:16:48 +0000 (+0000)
Subject: Don't allow inline asm statements to reference parameters in naked functions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e0e727e02529f654e4f8a1bfdd266149672dd9a9;p=clang

Don't allow inline asm statements to reference parameters in naked functions

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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@217200 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index cda5aa02ca..78f3eeb70c 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6993,6 +6993,8 @@ def err_filter_expression_integral : Error<
 
 def err_non_asm_stmt_in_naked_function : Error<
   "non-ASM statement in naked function is not supported">;
+def err_asm_naked_parm_ref : Error<
+  "parameter references not allowed in naked functions">;
 
 // OpenCL warnings and errors.
 def err_invalid_astype_of_different_size : Error<
diff --git a/lib/Sema/SemaStmtAsm.cpp b/lib/Sema/SemaStmtAsm.cpp
index 47a7672ae1..989999f18d 100644
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -405,6 +405,19 @@ ExprResult Sema::LookupInlineAsmIdentifier(CXXScopeSpec &SS,
   Result = CheckPlaceholderExpr(Result.get());
   if (!Result.isUsable()) return Result;
 
+  // Referring to parameters is not allowed in naked functions.
+  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Result.get())) {
+    if (ParmVarDecl *Parm = dyn_cast<ParmVarDecl>(DRE->getDecl())) {
+      if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Parm->getDeclContext())) {
+        if (Func->hasAttr<NakedAttr>()) {
+          Diag(Id.getLocStart(), diag::err_asm_naked_parm_ref);
+          Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
+          return ExprError();
+        }
+      }
+    }
+  }
+
   QualType T = Result.get()->getType();
 
   // For now, reject dependent types.
diff --git a/test/Sema/attr-naked.c b/test/Sema/attr-naked.c
index c1ad52c454..f6c26b29fc 100644
--- a/test/Sema/attr-naked.c
+++ b/test/Sema/attr-naked.c
@@ -18,3 +18,8 @@ __attribute__((naked)) int t4() {
   asm("movl $42, %eax");
   asm("retl");
 }
+
+__attribute__((naked)) int t5(int x) {
+  asm("movl x, %eax");
+  asm("retl");
+}
diff --git a/test/Sema/ms-inline-asm.c b/test/Sema/ms-inline-asm.c
index d4227027d7..358b0bd454 100644
--- a/test/Sema/ms-inline-asm.c
+++ b/test/Sema/ms-inline-asm.c
@@ -103,3 +103,14 @@ void t4() {
 void test_operand_size() {
   __asm { call word t4 } // expected-error {{Expected 'PTR' or 'ptr' token!}}
 }
+
+__declspec(naked) int t5(int x) { // expected-note {{attribute is here}}
+  asm { movl eax, x } // expected-error {{parameter references not allowed in naked functions}}
+  asm { retl }
+}
+
+int y;
+__declspec(naked) int t6(int x) {
+  asm { mov eax, y } // No error.
+  asm { ret }
+}