Fix an asan use-after-free bug introduced by the asm printer

changes to remove non-Function based subtargets out of the asm
printer. For module level emission we'll need to construct up
an MCSubtargetInfo so that we can encode instructions for
emission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230050 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index c31d024003f3d722710409a012d1f3999f35b910..480b790a99b060a8b82e6a56f4add3a51359c0ab 100644 (file)
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -1303,7 +1303,17 @@ static MCSymbol *GetAnonSym(MCSymbol *Sym, MCContext &Ctx) {
 void PPCDarwinAsmPrinter::
 EmitFunctionStubs(const MachineModuleInfoMachO::SymbolListTy &Stubs) {
   bool isPPC64 = TM.getDataLayout()->getPointerSizeInBits() == 64;
-  
+
+  // Construct a local MCSubtargetInfo and shadow EmitToStreamer here.
+  // This is because the MachineFunction won't exist (but have not yet been
+  // freed) and since we're at the global level we can use the default
+  // constructed subtarget.
+  std::unique_ptr<MCSubtargetInfo> STI(TM.getTarget().createMCSubtargetInfo(
+      TM.getTargetTriple(), TM.getTargetCPU(), TM.getTargetFeatureString()));
+  auto EmitToStreamer = [&STI] (MCStreamer &S, const MCInst &Inst) {
+    S.EmitInstruction(Inst, *STI);
+  };
+
   const TargetLoweringObjectFileMachO &TLOFMacho = 
     static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());