llvm-6502/lib/Target/PowerPC/PPCMCInstLower.cpp
Ulrich Weigand edaa58ee66 [PowerPC] Clean up generation of ha16() / lo16() markers
When targeting the Darwin assembler, we need to generate markers ha16() and
lo16() to designate the high and low parts of a (symbolic) immediate.  This
is necessary not just for plain symbols, but also for certain symbolic
expression, typically along the lines of ha16(A - B).  The latter doesn't
work when simply using VariantKind flags on the symbol reference.
This is why the current back-end uses hacks (explicitly called out as such
via multiple FIXMEs) in the symbolLo/symbolHi print methods.

This patch uses target-defined MCExpr codes to represent the Darwin
ha16/lo16 constructs, following along the lines of the equivalent solution
used by the ARM back end to handle their :upper16: / :lower16: markers.
This allows us to get rid of special handling both in the symbolLo/symbolHi
print method and in the common code MCExpr::print routine.  Instead, the
ha16 / lo16 markers are printed simply in a custom print routine for the
target MCExpr types.  (As a result, the symbolLo/symbolHi print methods
can now replaced by a single printS16ImmOperand routine that also handles
symbolic operands.)

The patch also provides a EvaluateAsRelocatableImpl routine to handle
ha16/lo16 constructs.  This is not actually used at the moment by any
in-tree code, but is provided as it makes merging into David Fang's
out-of-tree Mach-O object writer simpler.

Since there is no longer any need to treat VK_PPC_GAS_HA16 and
VK_PPC_DARWIN_HA16 differently, they are merged into a single
VK_PPC_ADDR16_HA (and likewise for the _LO16 types).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182616 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-23 22:26:41 +00:00

214 lines
7.0 KiB
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//===-- PPCMCInstLower.cpp - Convert PPC MachineInstr to an MCInst --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains code to lower PPC MachineInstrs to their corresponding
// MCInst records.
//
//===----------------------------------------------------------------------===//
#include "PPC.h"
#include "MCTargetDesc/PPCMCExpr.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Target/Mangler.h"
using namespace llvm;
static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
}
static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
MCContext &Ctx = AP.OutContext;
SmallString<128> Name;
if (!MO.isGlobal()) {
assert(MO.isSymbol() && "Isn't a symbol reference");
Name += AP.MAI->getGlobalPrefix();
Name += MO.getSymbolName();
} else {
const GlobalValue *GV = MO.getGlobal();
bool isImplicitlyPrivate = false;
if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB ||
(MO.getTargetFlags() & PPCII::MO_NLP_FLAG))
isImplicitlyPrivate = true;
AP.Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
}
// If the target flags on the operand changes the name of the symbol, do that
// before we return the symbol.
if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB) {
Name += "$stub";
const char *PGP = AP.MAI->getPrivateGlobalPrefix();
const char *Prefix = "";
if (!Name.startswith(PGP)) {
// http://llvm.org/bugs/show_bug.cgi?id=15763
// all stubs and lazy_ptrs should be local symbols, which need leading 'L'
Prefix = PGP;
}
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Twine(Prefix) + Twine(Name));
MachineModuleInfoImpl::StubValueTy &StubSym =
getMachOMMI(AP).getFnStubEntry(Sym);
if (StubSym.getPointer())
return Sym;
if (MO.isGlobal()) {
StubSym =
MachineModuleInfoImpl::
StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
} else {
Name.erase(Name.end()-5, Name.end());
StubSym =
MachineModuleInfoImpl::
StubValueTy(Ctx.GetOrCreateSymbol(Name.str()), false);
}
return Sym;
}
// If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
// then add the suffix.
if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
Name += "$non_lazy_ptr";
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
MachineModuleInfoMachO &MachO = getMachOMMI(AP);
MachineModuleInfoImpl::StubValueTy &StubSym =
(MO.getTargetFlags() & PPCII::MO_NLP_HIDDEN_FLAG) ?
MachO.getHiddenGVStubEntry(Sym) : MachO.getGVStubEntry(Sym);
if (StubSym.getPointer() == 0) {
assert(MO.isGlobal() && "Extern symbol not handled yet");
StubSym = MachineModuleInfoImpl::
StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
}
return Sym;
}
return Ctx.GetOrCreateSymbol(Name.str());
}
static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
AsmPrinter &Printer, bool isDarwin) {
MCContext &Ctx = Printer.OutContext;
MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
if (!isDarwin) {
switch (access) {
case PPCII::MO_HA16:
RefKind = MCSymbolRefExpr::VK_PPC_ADDR16_HA;
break;
case PPCII::MO_LO16:
RefKind = MCSymbolRefExpr::VK_PPC_ADDR16_LO;
break;
case PPCII::MO_TPREL16_HA:
RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_HA;
break;
case PPCII::MO_TPREL16_LO:
RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_LO;
break;
case PPCII::MO_DTPREL16_LO:
RefKind = MCSymbolRefExpr::VK_PPC_DTPREL16_LO;
break;
case PPCII::MO_TLSLD16_LO:
RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD16_LO;
break;
case PPCII::MO_TOC16_LO:
RefKind = MCSymbolRefExpr::VK_PPC_TOC16_LO;
break;
}
}
const MCExpr *Expr = MCSymbolRefExpr::Create(Symbol, RefKind, Ctx);
if (!MO.isJTI() && MO.getOffset())
Expr = MCBinaryExpr::CreateAdd(Expr,
MCConstantExpr::Create(MO.getOffset(), Ctx),
Ctx);
// Subtract off the PIC base if required.
if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
const MachineFunction *MF = MO.getParent()->getParent()->getParent();
const MCExpr *PB = MCSymbolRefExpr::Create(MF->getPICBaseSymbol(), Ctx);
Expr = MCBinaryExpr::CreateSub(Expr, PB, Ctx);
}
// Add Darwin ha16() / lo16() markers if required.
if (isDarwin) {
switch (access) {
case PPCII::MO_HA16:
Expr = PPCMCExpr::CreateHa16(Expr, Ctx);
break;
case PPCII::MO_LO16:
Expr = PPCMCExpr::CreateLo16(Expr, Ctx);
break;
}
}
return MCOperand::CreateExpr(Expr);
}
void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
AsmPrinter &AP, bool isDarwin) {
OutMI.setOpcode(MI->getOpcode());
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
MCOperand MCOp;
switch (MO.getType()) {
default:
MI->dump();
llvm_unreachable("unknown operand type");
case MachineOperand::MO_Register:
assert(!MO.getSubReg() && "Subregs should be eliminated!");
MCOp = MCOperand::CreateReg(MO.getReg());
break;
case MachineOperand::MO_Immediate:
MCOp = MCOperand::CreateImm(MO.getImm());
break;
case MachineOperand::MO_MachineBasicBlock:
MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
MO.getMBB()->getSymbol(), AP.OutContext));
break;
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
break;
case MachineOperand::MO_JumpTableIndex:
MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
break;
case MachineOperand::MO_ConstantPoolIndex:
MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
break;
case MachineOperand::MO_BlockAddress:
MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
isDarwin);
break;
case MachineOperand::MO_RegisterMask:
continue;
}
OutMI.addOperand(MCOp);
}
}