AArch64/ARM64: port across stub handling for ELF C++ exceptions.

The most important part here is that we should actuall emit the stubs we refer
to in the exception table, but as a side issue this uses more sensible & GCC
compatible representations for some of the bits of information.

llvm-svn: 206380

llvm/lib/MC/MCObjectFileInfo.cpp

@@ -289,8 +289,9 @@ void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
       TTypeEncoding = (CMModel == CodeModel::Small)
         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
     }
-  }  else if (T.getArch() == Triple::aarch64 ||
-              T.getArch() == Triple::aarch64_be ) {
+  } else if (T.getArch() == Triple::aarch64 ||
+             T.getArch() == Triple::aarch64_be ||
+             T.getArch() == Triple::arm64) {
     // The small model guarantees static code/data size < 4GB, but not where it
     // will be in memory. Most of these could end up >2GB away so even a signed
     // pc-relative 32-bit address is insufficient, theoretically.

llvm/lib/Target/ARM64/ARM64AsmPrinter.cpp

@@ -17,6 +17,7 @@
 #include "ARM64MachineFunctionInfo.h"
 #include "ARM64MCInstLower.h"
 #include "ARM64RegisterInfo.h"
+#include "ARM64Subtarget.h"
 #include "InstPrinter/ARM64InstPrinter.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -24,6 +25,8 @@
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/StackMaps.h"
+#include "llvm/CodeGen/MachineModuleInfoImpls.h"
+#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/MC/MCAsmInfo.h"
@@ -39,13 +42,18 @@ using namespace llvm;
 namespace {
 
 class ARM64AsmPrinter : public AsmPrinter {
+  /// Subtarget - Keep a pointer to the ARM64Subtarget around so that we can
+  /// make the right decision when printing asm code for different targets.
+  const ARM64Subtarget *Subtarget;
+
   ARM64MCInstLower MCInstLowering;
   StackMaps SM;
 
 public:
   ARM64AsmPrinter(TargetMachine &TM, MCStreamer &Streamer)
-      : AsmPrinter(TM, Streamer), MCInstLowering(OutContext, *Mang, *this),
-        SM(*this), ARM64FI(NULL), LOHLabelCounter(0) {}
+      : AsmPrinter(TM, Streamer), Subtarget(&TM.getSubtarget<ARM64Subtarget>()),
+        MCInstLowering(OutContext, *Mang, *this), SM(*this), ARM64FI(NULL),
+        LOHLabelCounter(0) {}
 
   virtual const char *getPassName() const { return "ARM64 Assembly Printer"; }
 
@@ -119,6 +127,29 @@ void ARM64AsmPrinter::EmitEndOfAsmFile(Module &M) {
   // generates code that does this, it is always safe to set.
   OutStreamer.EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
   SM.serializeToStackMapSection();
+
+  // Emit a .data.rel section containing any stubs that were created.
+  if (Subtarget->isTargetELF()) {
+    const TargetLoweringObjectFileELF &TLOFELF =
+      static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());
+
+    MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
+
+    // Output stubs for external and common global variables.
+    MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
+    if (!Stubs.empty()) {
+      OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
+      const DataLayout *TD = TM.getDataLayout();
+
+      for (unsigned i = 0, e = Stubs.size(); i != e; ++i) {
+        OutStreamer.EmitLabel(Stubs[i].first);
+        OutStreamer.EmitSymbolValue(Stubs[i].second.getPointer(),
+                                    TD->getPointerSize(0));
+      }
+      Stubs.clear();
+    }
+  }
+
 }
 
 MachineLocation

llvm/test/CodeGen/AArch64/pic-eh-stubs.ll

@@ -1,5 +1,6 @@
 ; RUN: llc -mtriple=aarch64-none-linux-gnu -relocation-model=pic -o - %s | FileCheck %s
 ; RUN: llc -mtriple=aarch64_be-none-linux-gnu -relocation-model=pic -o - %s | FileCheck %s
+; RUN: llc -mtriple=arm64-none-linux-gnu -relocation-model=pic -o - %s | FileCheck %s
 
 ; Make sure exception-handling PIC code can be linked correctly. An alternative
 ; to the sequence described below would have .gcc_except_table itself writable
@@ -11,8 +12,8 @@
   ; ... referring indirectly to stubs for its typeinfo ...
 ; CHECK: // @TType Encoding = indirect pcrel sdata8
   ; ... one of which is "int"'s typeinfo
-; CHECK: .Ltmp7:
-; CHECK-NEXT: .xword  .L_ZTIi.DW.stub-.Ltmp7
+; CHECK: [[TYPEINFO_LBL:.Ltmp[0-9]+]]: // TypeInfo 1
+; CHECK-NEXT: .xword  .L_ZTIi.DW.stub-[[TYPEINFO_LBL]]
 
   ; .. and which is properly defined (in a writable section for the dynamic loader) later.
 ; CHECK: .section .data.rel,"aw"