From c6a42bafd645cdfe5a777e480f3064c1d8d172f1 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Thu, 3 Nov 2016 23:33:46 +0000
Subject: [PATCH] Sink all of the code relying on the MachO MachineModuleInfo
 to live behind the test that the MachineModuleInfo analysis was actually
 available and can be used.

While the MachO bits may well be reasonable to assume in the darwin
assembly printer, the analysis isn't constructively guaranteed anywhere
I could find so it seems safest to avoid crashing here.

This issue was found with PVS-Studio. Pretty sure the Clang Static
Anaylzer flags similar issues but we've probably never pointed it at
this code effectively.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285972 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCAsmPrinter.cpp | 98 +++++++++++++++-------------
 1 file changed, 51 insertions(+), 47 deletions(-)

diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index c347cfddc6d..81e2132c5db 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -1370,57 +1370,61 @@ bool PPCDarwinAsmPrinter::doFinalization(Module &M) {
   // Darwin/PPC always uses mach-o.
   const TargetLoweringObjectFileMachO &TLOFMacho =
       static_cast<const TargetLoweringObjectFileMachO &>(getObjFileLowering());
-  MachineModuleInfoMachO &MMIMacho =
-      MMI->getObjFileInfo<MachineModuleInfoMachO>();
-
-  if (MAI->doesSupportExceptionHandling() && MMI) {
-    // Add the (possibly multiple) personalities to the set of global values.
-    // Only referenced functions get into the Personalities list.
-    for (const Function *Personality : MMI->getPersonalities()) {
-      if (Personality) {
-        MCSymbol *NLPSym =
-            getSymbolWithGlobalValueBase(Personality, "$non_lazy_ptr");
-        MachineModuleInfoImpl::StubValueTy &StubSym =
-            MMIMacho.getGVStubEntry(NLPSym);
-        StubSym =
-            MachineModuleInfoImpl::StubValueTy(getSymbol(Personality), true);
+  if (MMI) {
+    MachineModuleInfoMachO &MMIMacho =
+        MMI->getObjFileInfo<MachineModuleInfoMachO>();
+
+    if (MAI->doesSupportExceptionHandling()) {
+      // Add the (possibly multiple) personalities to the set of global values.
+      // Only referenced functions get into the Personalities list.
+      for (const Function *Personality : MMI->getPersonalities()) {
+        if (Personality) {
+          MCSymbol *NLPSym =
+              getSymbolWithGlobalValueBase(Personality, "$non_lazy_ptr");
+          MachineModuleInfoImpl::StubValueTy &StubSym =
+              MMIMacho.getGVStubEntry(NLPSym);
+          StubSym =
+              MachineModuleInfoImpl::StubValueTy(getSymbol(Personality), true);
+        }
       }
     }
-  }
 
-  // Output stubs for dynamically-linked functions.
-  MachineModuleInfoMachO::SymbolListTy Stubs = MMIMacho.GetGVStubList();
-
-  // Output macho stubs for external and common global variables.
-  if (!Stubs.empty()) {
-    // Switch with ".non_lazy_symbol_pointer" directive.
-    OutStreamer->SwitchSection(TLOFMacho.getNonLazySymbolPointerSection());
-    EmitAlignment(isPPC64 ? 3 : 2);
-
-    for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
-      // L_foo$stub:
-      OutStreamer->EmitLabel(Stubs[i].first);
-      //   .indirect_symbol _foo
-      MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
-      OutStreamer->EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
-
-      if (MCSym.getInt())
-        // External to current translation unit.
-        OutStreamer->EmitIntValue(0, isPPC64 ? 8 : 4/*size*/);
-      else
-        // Internal to current translation unit.
-        //
-        // When we place the LSDA into the TEXT section, the type info pointers
-        // need to be indirect and pc-rel. We accomplish this by using NLPs.
-        // However, sometimes the types are local to the file. So we need to
-        // fill in the value for the NLP in those cases.
-        OutStreamer->EmitValue(MCSymbolRefExpr::create(MCSym.getPointer(),
-                                                       OutContext),
-                              isPPC64 ? 8 : 4/*size*/);
-    }
+    // Output stubs for dynamically-linked functions.
+    MachineModuleInfoMachO::SymbolListTy Stubs = MMIMacho.GetGVStubList();
+
+    // Output macho stubs for external and common global variables.
+    if (!Stubs.empty()) {
+      // Switch with ".non_lazy_symbol_pointer" directive.
+      OutStreamer->SwitchSection(TLOFMacho.getNonLazySymbolPointerSection());
+      EmitAlignment(isPPC64 ? 3 : 2);
+
+      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
+        // L_foo$stub:
+        OutStreamer->EmitLabel(Stubs[i].first);
+        //   .indirect_symbol _foo
+        MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
+        OutStreamer->EmitSymbolAttribute(MCSym.getPointer(),
+                                         MCSA_IndirectSymbol);
+
+        if (MCSym.getInt())
+          // External to current translation unit.
+          OutStreamer->EmitIntValue(0, isPPC64 ? 8 : 4 /*size*/);
+        else
+          // Internal to current translation unit.
+          //
+          // When we place the LSDA into the TEXT section, the type info
+          // pointers
+          // need to be indirect and pc-rel. We accomplish this by using NLPs.
+          // However, sometimes the types are local to the file. So we need to
+          // fill in the value for the NLP in those cases.
+          OutStreamer->EmitValue(
+              MCSymbolRefExpr::create(MCSym.getPointer(), OutContext),
+              isPPC64 ? 8 : 4 /*size*/);
+      }
 
-    Stubs.clear();
-    OutStreamer->AddBlankLine();
+      Stubs.clear();
+      OutStreamer->AddBlankLine();
+    }
   }
 
   // Funny Darwin hack: This flag tells the linker that no global symbols
-- 
2.40.0