Selecting the address from a very long chain of GEPs can blow the stack.

[oota-llvm.git] / lib / Target / PowerPC / PPCTargetObjectFile.cpp

diff --git a/lib/Target/PowerPC/PPCTargetObjectFile.cpp b/lib/Target/PowerPC/PPCTargetObjectFile.cpp
index de81040021e28baf0eaa2fa39e94bc94fc0f67ee..ec1e606eee56fa32ed1d7ce1d73b3236e78f52d2 100644 (file)
--- a/lib/Target/PowerPC/PPCTargetObjectFile.cpp
+++ b/lib/Target/PowerPC/PPCTargetObjectFile.cpp
@@ -1,4 +1,4 @@
-//===-- llvm/Target/PPCTargetObjectFile.cpp - PPC Object Info Impl --------===//
+//===-- PPCTargetObjectFile.cpp - PPC Object Info -------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -8,26 +8,60 @@
 //===----------------------------------------------------------------------===//
 
 #include "PPCTargetObjectFile.h"
-#include "PPCSubtarget.h"
-#include "llvm/MC/MCSectionMachO.h"
-#include "llvm/Support/Dwarf.h"
-#include "llvm/Target/TargetMachine.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSectionELF.h"
+#include "llvm/Target/Mangler.h"
+
 using namespace llvm;
-using namespace dwarf;
 
-//===----------------------------------------------------------------------===//
-//                              Mach-O Target
-//===----------------------------------------------------------------------===//
+void
+PPC64LinuxTargetObjectFile::
+Initialize(MCContext &Ctx, const TargetMachine &TM) {
+  TargetLoweringObjectFileELF::Initialize(Ctx, TM);
+  InitializeELF(TM.Options.UseInitArray);
+}
+
+const MCSection * PPC64LinuxTargetObjectFile::
+SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
+                       Mangler *Mang, const TargetMachine &TM) const {
 
-void PPCMachOTargetObjectFile::Initialize(MCContext &Ctx,
-                                          const TargetMachine &TM) {
-  TargetLoweringObjectFileMachO::Initialize(Ctx, TM);
+  const MCSection *DefaultSection = 
+    TargetLoweringObjectFileELF::SelectSectionForGlobal(GV, Kind, Mang, TM);
 
-  // Exception Handling.
-  LSDASection = getMachOSection("__TEXT", "__gcc_except_tab", 0,
-                                SectionKind::getReadOnlyWithRel());
+  if (DefaultSection != ReadOnlySection)
+    return DefaultSection;
+
+  // Here override ReadOnlySection to DataRelROSection for PPC64 SVR4 ABI
+  // when we have a constant that contains global relocations.  This is
+  // necessary because of this ABI's handling of pointers to functions in
+  // a shared library.  The address of a function is actually the address
+  // of a function descriptor, which resides in the .opd section.  Generated
+  // code uses the descriptor directly rather than going via the GOT as some
+  // other ABIs do, which means that initialized function pointers must
+  // reference the descriptor.  The linker must convert copy relocs of
+  // pointers to functions in shared libraries into dynamic relocations,
+  // because of an ordering problem with initialization of copy relocs and
+  // PLT entries.  The dynamic relocation will be initialized by the dynamic
+  // linker, so we must use DataRelROSection instead of ReadOnlySection.
+  // For more information, see the description of ELIMINATE_COPY_RELOCS in
+  // GNU ld.
+  const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
+
+  if (GVar && GVar->isConstant() &&
+      (GVar->getInitializer()->getRelocationInfo() ==
+       Constant::GlobalRelocations))
+    return DataRelROSection;
+
+  return DefaultSection;
 }
 
-unsigned PPCMachOTargetObjectFile::getTTypeEncoding() const {
-  return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
+const MCExpr *PPC64LinuxTargetObjectFile::
+getDebugThreadLocalSymbol(const MCSymbol *Sym) const {
+  const MCExpr *Expr =
+    MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_PPC_DTPREL, getContext());
+  return MCBinaryExpr::CreateAdd(Expr,
+                                 MCConstantExpr::Create(0x8000, getContext()),
+                                 getContext());
 }
+