Subzero: Add Non-SFI support for x86-32.

src/IceInstX86BaseImpl.h

Index: src/IceInstX86BaseImpl.h
diff --git a/src/IceInstX86BaseImpl.h b/src/IceInstX86BaseImpl.h
index 96ed422920d8cd36073f9736f48aedb4559ac16d..addb59964479e5e509b8902923405ec8ab2d0491 100644
--- a/src/IceInstX86BaseImpl.h
+++ b/src/IceInstX86BaseImpl.h
@@ -24,6 +24,7 @@
 #include "IceInst.h"
 #include "IceOperand.h"
 #include "IceTargetLowering.h"
+#include "IceTargetLoweringX86Base.h"
 
 namespace Ice {
 
@@ -57,6 +58,10 @@ InstImpl<TraitsType>::InstX86FakeRMW::InstX86FakeRMW(Cfg *Func, Operand *Data,
 }
 
 template <typename TraitsType>
+InstImpl<TraitsType>::InstX86GetIP::InstX86GetIP(Cfg *Func, Variable *Dest)
+    : InstX86Base(Func, InstX86Base::GetIP, 0, Dest) {}
+
+template <typename TraitsType>
 InstImpl<TraitsType>::InstX86Mul::InstX86Mul(Cfg *Func, Variable *Dest,
                                              Variable *Source1,
                                              Operand *Source2)
@@ -391,6 +396,55 @@ void InstImpl<TraitsType>::InstX86FakeRMW::dump(const Cfg *Func) const {
 }
 
 template <typename TraitsType>
+void InstImpl<TraitsType>::InstX86GetIP::emit(const Cfg *Func) const {
+  if (!BuildDefs::dump())
+    return;
+  Ostream &Str = Func->getContext()->getStrEmit();
+  assert(this->getDest()->hasReg());
+  Str << "\t"
+         "addl\t$_GLOBAL_OFFSET_TABLE_, ";
+  this->getDest()->emit(Func);
+}
+
+template <typename TraitsType>
+void InstImpl<TraitsType>::InstX86GetIP::emitIAS(const Cfg *Func) const {
+  if (Func->getContext()->getFlags().getOutFileType() == FT_Iasm) {
+    // TODO(stichnot): Find a workaround for llvm-mc's inability to handle
+    // something like ".long _GLOBAL_OFFSET_TABLE_ + ." .  One possibility is to
+    // just use hybrid iasm output for this add instruction.
+    llvm::report_fatal_error(
+        "Iasm support for _GLOBAL_OFFSET_TABLE_ not implemented");
+  }
+  Assembler *Asm = Func->getAssembler<Assembler>();
+  assert(this->getDest()->hasReg());
+  GPRRegister Reg = Traits::getEncodedGPR(this->getDest()->getRegNum());
+  Constant *GlobalOffsetTable =
+      Func->getContext()->getConstantExternSym("_GLOBAL_OFFSET_TABLE_");
+  AssemblerFixup *Fixup = Asm->createFixup(Traits::FK_GotPC, GlobalOffsetTable);
+  intptr_t OrigPos = Asm->getBufferSize();
+  constexpr int32_t TempDisp = 0;
+  constexpr int32_t ImmediateWidth = 4;
+  // Emit the add instruction once, in a preliminary fashion, to find its total
+  // size.  TODO(stichnot): IceType_i32 should really be something that
+  // represents the target's pointer type.
+  Asm->add(IceType_i32, Reg, AssemblerImmediate(TempDisp, Fixup));
+  const int32_t Disp = Asm->getBufferSize() - OrigPos - ImmediateWidth;
+  // Now roll back and emit the add instruction again, this time with the
+  // correct displacement.
+  Asm->setBufferSize(OrigPos);
+  Asm->add(IceType_i32, Reg, AssemblerImmediate(Disp, Fixup));
+}
+
+template <typename TraitsType>
+void InstImpl<TraitsType>::InstX86GetIP::dump(const Cfg *Func) const {
+  if (!BuildDefs::dump())
+    return;
+  Ostream &Str = Func->getContext()->getStrDump();
+  this->getDest()->dump(Func);
+  Str << " = call getIP";
+}
+
+template <typename TraitsType>
 void InstImpl<TraitsType>::InstX86Label::emit(const Cfg *Func) const {
   if (!BuildDefs::dump())
     return;
@@ -679,7 +733,8 @@ void InstImpl<TraitsType>::emitIASRegOpTyGPR(const Cfg *Func, Type Ty,
   } else if (const auto *Imm = llvm::dyn_cast<ConstantInteger32>(Src)) {
     (Asm->*(Emitter.GPRImm))(Ty, VarReg, AssemblerImmediate(Imm->getValue()));
   } else if (const auto *Reloc = llvm::dyn_cast<ConstantRelocatable>(Src)) {
-    AssemblerFixup *Fixup = Asm->createFixup(Traits::RelFixup, Reloc);
+    AssemblerFixup *Fixup =
+        Asm->createFixup(Traits::TargetLowering::getAbsFixup(), Reloc);
     (Asm->*(Emitter.GPRImm))(Ty, VarReg,
                              AssemblerImmediate(Reloc->getOffset(), Fixup));
   } else if (const auto *Split = llvm::dyn_cast<VariableSplit>(Src)) {
@@ -703,7 +758,8 @@ void InstImpl<TraitsType>::emitIASAddrOpTyGPR(const Cfg *Func, Type Ty,
   } else if (const auto *Imm = llvm::dyn_cast<ConstantInteger32>(Src)) {
     (Asm->*(Emitter.AddrImm))(Ty, Addr, AssemblerImmediate(Imm->getValue()));
   } else if (const auto *Reloc = llvm::dyn_cast<ConstantRelocatable>(Src)) {
-    AssemblerFixup *Fixup = Asm->createFixup(Traits::RelFixup, Reloc);
+    AssemblerFixup *Fixup =
+        Asm->createFixup(Traits::TargetLowering::getAbsFixup(), Reloc);
     (Asm->*(Emitter.AddrImm))(Ty, Addr,
                               AssemblerImmediate(Reloc->getOffset(), Fixup));
   } else {