add a way to disable all builtins, wire it up to opt's -disable-simplifylibcalls flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125978 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLibraryInfo.h

@@ -55,6 +55,10 @@ public:
   void setAvailable(LibFunc::Func F) {
     AvailableArray[F/8] |= 1 << (F&7);
   }
+  
+  /// disableAllFunctions - This disables all builtins, which is used for
+  /// options like -fno-builtin.
+  void disableAllFunctions();
 };
 
 } // end namespace llvm

lib/Target/TargetLibraryInfo.cpp

@@ -47,3 +47,9 @@ TargetLibraryInfo::TargetLibraryInfo(const Triple &T) : ImmutablePass(ID) {
   
   initialize(*this, T);
 }
+
+/// disableAllFunctions - This disables all builtins, which is used for options
+/// like -fno-builtin.
+void TargetLibraryInfo::disableAllFunctions() {
+  memset(AvailableArray, 0, sizeof(AvailableArray));
+}

tools/opt/opt.cpp

@@ -532,8 +532,12 @@ int main(int argc, char **argv) {
   PassManager Passes;
 
   // Add an appropriate TargetLibraryInfo pass for the module's triple.
-  if (!M->getTargetTriple().empty())
+  TargetLibraryInfo *TLI = new TargetLibraryInfo(Triple(M->getTargetTriple()));
-    Passes.add(new TargetLibraryInfo(Triple(M->getTargetTriple())));
+  
+  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
+  if (DisableSimplifyLibCalls)
+    TLI->disableAllFunctions();
+  Passes.add(TLI);
   
   // Add an appropriate TargetData instance for this module.
   TargetData *TD = 0;