Disable all recognition of main() in -ffreestanding. Addresses bug #4720.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@79070 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 7 insertions, 6 deletions

diff --git a/lib/AST/Decl.cpp b/lib/AST/Decl.cpp
index 6d2f2301ba..c91cb1dba2 100644
--- a/lib/AST/Decl.cpp
+++ b/lib/AST/Decl.cpp
@@ -414,8 +414,9 @@ void FunctionDecl::setBody(Stmt *B) {
     EndRangeLoc = B->getLocEnd();
 }
 
-bool FunctionDecl::isMain() const {
-  return getDeclContext()->getLookupContext()->isTranslationUnit() &&
+bool FunctionDecl::isMain(ASTContext &Context) const {
+  return !Context.getLangOptions().Freestanding &&
+    getDeclContext()->getLookupContext()->isTranslationUnit() &&
     getIdentifier() && getIdentifier()->isStr("main");
 }
 
diff --git a/lib/CodeGen/Mangle.cpp b/lib/CodeGen/Mangle.cpp
index 341e230e90..71b84e7001 100644
--- a/lib/CodeGen/Mangle.cpp
+++ b/lib/CodeGen/Mangle.cpp
@@ -91,7 +91,7 @@ bool CXXNameMangler::mangleFunctionDecl(const FunctionDecl *FD) {
   // name mangling (always).
   if (!FD->hasAttr<OverloadableAttr>()) {
     // C functions are not mangled, and "main" is never mangled.
-    if (!Context.getLangOptions().CPlusPlus || FD->isMain())
+    if (!Context.getLangOptions().CPlusPlus || FD->isMain(Context))
       return false;
     
     // No mangling in an "implicit extern C" header. 
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index ab5578b378..d75f322aa5 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -2766,7 +2766,7 @@ void Sema::CheckFunctionDeclaration(FunctionDecl *NewFD, NamedDecl *&PrevDecl,
     return NewFD->setInvalidDecl();
   }
 
-  if (NewFD->isMain()) CheckMain(NewFD);
+  if (NewFD->isMain(Context)) CheckMain(NewFD);
 
   // Semantic checking for this function declaration (in isolation).
   if (getLangOptions().CPlusPlus) {
@@ -3542,7 +3542,7 @@ Sema::DeclPtrTy Sema::ActOnStartOfFunctionDef(Scope *FnBodyScope, DeclPtrTy D) {
   //   definition itself provides a prototype. The aim is to detect
   //   global functions that fail to be declared in header files.
   if (!FD->isInvalidDecl() && FD->isGlobal() && !isa<CXXMethodDecl>(FD) &&
-      !FD->isMain()) {
+      !FD->isMain(Context)) {
     bool MissingPrototype = true;
     for (const FunctionDecl *Prev = FD->getPreviousDeclaration();
          Prev; Prev = Prev->getPreviousDeclaration()) {
@@ -3608,7 +3608,7 @@ Sema::DeclPtrTy Sema::ActOnFinishFunctionBody(DeclPtrTy D, StmtArg BodyArg,
   Stmt *Body = BodyArg.takeAs<Stmt>();
   if (FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(dcl)) {
     FD->setBody(Body);
-    if (FD->isMain())
+    if (FD->isMain(Context))
       // C and C++ allow for main to automagically return 0.
       // Implements C++ [basic.start.main]p5 and C99 5.1.2.2.3.
       FD->setHasImplicitReturnZero(true);