[llvm] r285972 - Sink all of the code relying on the MachO MachineModuleInfo to live

[Chandler Carruth via llvm-commits]

Author: chandlerc
Date: Thu Nov  3 18:33:46 2016
New Revision: 285972

URL: http://llvm.org/viewvc/llvm-project?rev=285972&view=rev
Log:
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.

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCAsmPrinter.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCAsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCAsmPrinter.cpp?rev=285972&r1=285971&r2=285972&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCAsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCAsmPrinter.cpp Thu Nov  3 18:33:46 2016
@@ -1370,57 +1370,61 @@ bool PPCDarwinAsmPrinter::doFinalization
   // 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 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$stub:
-      OutStreamer->EmitLabel(Stubs[i].first);
-      //   .indirect_symbol _foo
-      MachineModuleInfoImpl::StubValueTy &MCSym = Stubs[i].second;
-      OutStreamer->EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
-
-      if (MCSym.getInt())
-        // External to current translation unit.
-        OutStreamer->EmitIntValue(0, isPPC64 ? 8 : 4/*size*/);
-      else
-        // Internal to current translation unit.
-        //
-        // When we place the LSDA into the TEXT section, the type info pointers
-        // need to be indirect and pc-rel. We accomplish this by using NLPs.
-        // However, sometimes the types are local to the file. So we need to
-        // fill in the value for the NLP in those cases.
-        OutStreamer->EmitValue(MCSymbolRefExpr::create(MCSym.getPointer(),
-                                                       OutContext),
-                              isPPC64 ? 8 : 4/*size*/);
-    }
+    // Output macho stubs for external and common global variables.
+    if (!Stubs.empty()) {
+      // Switch with ".non_lazy_symbol_pointer" directive.
+      OutStreamer->SwitchSection(TLOFMacho.getNonLazySymbolPointerSection());
+      EmitAlignment(isPPC64 ? 3 : 2);
+
+      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
+        // L_foo$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