Add -ffreestanding to suppress the implicit declaration of library builtins like printf and malloc. Fixes PR3586

llvm-svn: 64566

3 files changed, 16 insertions, 8 deletions

diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 652fcdf8080..f724524f028 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -39,7 +39,7 @@ ASTContext::ASTContext(const LangOptions& LOpts, SourceManager &SM,
 {  
   if (size_reserve > 0) Types.reserve(size_reserve);    
   InitBuiltinTypes();
-  BuiltinInfo.InitializeBuiltins(idents, Target);
+  BuiltinInfo.InitializeBuiltins(idents, Target, LangOpts.Freestanding);
   TUDecl = TranslationUnitDecl::Create(*this);
 }
 
diff --git a/clang/lib/AST/Builtins.cpp b/clang/lib/AST/Builtins.cpp
index 92b05975f55..cf2954de2f6 100644
--- a/clang/lib/AST/Builtins.cpp
+++ b/clang/lib/AST/Builtins.cpp
@@ -19,8 +19,8 @@
 using namespace clang;
 
 static const Builtin::Info BuiltinInfo[] = {
-  { "not a builtin function", 0, 0 },
-#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS },
+  { "not a builtin function", 0, 0, false },
+#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS, false },
 #include "clang/AST/Builtins.def"
 };
 
@@ -36,17 +36,25 @@ const Builtin::Info &Builtin::Context::GetRecord(unsigned ID) const {
 /// appropriate builtin ID # and mark any non-portable builtin identifiers as
 /// such.
 void Builtin::Context::InitializeBuiltins(IdentifierTable &Table,
-                                          const TargetInfo &Target) {
+                                          const TargetInfo &Target,
+                                          bool Freestanding) {
   // Step #1: mark all target-independent builtins with their ID's.
   for (unsigned i = Builtin::NotBuiltin+1; i != Builtin::FirstTSBuiltin; ++i)
-    Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
+    if (!BuiltinInfo[i].Suppressed &&
+        (!Freestanding || 
+         !strchr(BuiltinInfo[i].Attributes, 'f')))
+      Table.get(BuiltinInfo[i].Name).setBuiltinID(i);
   
   // Step #2: Get target builtins.
   Target.getTargetBuiltins(TSRecords, NumTSRecords);
 
   // Step #3: Register target-specific builtins.
   for (unsigned i = 0, e = NumTSRecords; i != e; ++i)
-    Table.get(TSRecords[i].Name).setBuiltinID(i+Builtin::FirstTSBuiltin);
+    if (!TSRecords[i].Suppressed &&
+        (!Freestanding || 
+         (BuiltinInfo[i].Attributes && 
+          !strchr(BuiltinInfo[i].Attributes, 'f'))))
+      Table.get(TSRecords[i].Name).setBuiltinID(i+Builtin::FirstTSBuiltin);
 }
 
 std::string Builtin::Context::getHeaderName(unsigned ID) const {
diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index ad7d6d57974..3e724eb3969 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -296,7 +296,7 @@ public:
 };
 
 const Builtin::Info PPCTargetInfo::BuiltinInfo[] = {
-#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS },
+#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS, false },
 #include "clang/AST/PPCBuiltins.def"
 };
 
@@ -438,7 +438,7 @@ public:
 namespace {
 // Namespace for x86 abstract base class
 const Builtin::Info BuiltinInfo[] = {
-#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS },
+#define BUILTIN(ID, TYPE, ATTRS) { #ID, TYPE, ATTRS, false },
 #include "clang/AST/X86Builtins.def"
 };