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//===- MCLinkerOptimizationHint.h - LOH interface ---------------*- C++ -*-===//
//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file declares some helpers classes to handle Linker Optimization Hint
// (LOH).
//
// FIXME: LOH interface supports only MachO format at the moment.
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
#define LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include <cassert>
#include <cstdint>
namespace llvm {
class MachObjectWriter;
class MCAssembler;
class MCSymbol;
class raw_ostream;
/// Linker Optimization Hint Type.
enum MCLOHType {
MCLOH_AdrpAdrp = 0x1u, ///< Adrp xY, _v1@PAGE -> Adrp xY, _v2@PAGE.
MCLOH_AdrpLdr = 0x2u, ///< Adrp _v@PAGE -> Ldr _v@PAGEOFF.
MCLOH_AdrpAddLdr = 0x3u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Ldr.
MCLOH_AdrpLdrGotLdr = 0x4u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Ldr.
MCLOH_AdrpAddStr = 0x5u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF -> Str.
MCLOH_AdrpLdrGotStr = 0x6u, ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF -> Str.
MCLOH_AdrpAdd = 0x7u, ///< Adrp _v@PAGE -> Add _v@PAGEOFF.
MCLOH_AdrpLdrGot = 0x8u ///< Adrp _v@GOTPAGE -> Ldr _v@GOTPAGEOFF.
};
static inline StringRef MCLOHDirectiveName() {
return StringRef(".loh");
}
static inline bool isValidMCLOHType(unsigned Kind) {
return Kind >= MCLOH_AdrpAdrp && Kind <= MCLOH_AdrpLdrGot;
}
static inline int MCLOHNameToId(StringRef Name) {
#define MCLOHCaseNameToId(Name) .Case(#Name, MCLOH_ ## Name)
return StringSwitch<int>(Name)
MCLOHCaseNameToId(AdrpAdrp)
MCLOHCaseNameToId(AdrpLdr)
MCLOHCaseNameToId(AdrpAddLdr)
MCLOHCaseNameToId(AdrpLdrGotLdr)
MCLOHCaseNameToId(AdrpAddStr)
MCLOHCaseNameToId(AdrpLdrGotStr)
MCLOHCaseNameToId(AdrpAdd)
MCLOHCaseNameToId(AdrpLdrGot)
.Default(-1);
#undef MCLOHCaseNameToId
}
static inline StringRef MCLOHIdToName(MCLOHType Kind) {
#define MCLOHCaseIdToName(Name) case MCLOH_ ## Name: return StringRef(#Name);
switch (Kind) {
MCLOHCaseIdToName(AdrpAdrp);
MCLOHCaseIdToName(AdrpLdr);
MCLOHCaseIdToName(AdrpAddLdr);
MCLOHCaseIdToName(AdrpLdrGotLdr);
MCLOHCaseIdToName(AdrpAddStr);
MCLOHCaseIdToName(AdrpLdrGotStr);
MCLOHCaseIdToName(AdrpAdd);
MCLOHCaseIdToName(AdrpLdrGot);
}
return StringRef();
#undef MCLOHCaseIdToName
}
static inline int MCLOHIdToNbArgs(MCLOHType Kind) {
switch (Kind) {
// LOH with two arguments
case MCLOH_AdrpAdrp:
case MCLOH_AdrpLdr:
case MCLOH_AdrpAdd:
case MCLOH_AdrpLdrGot:
return 2;
// LOH with three arguments
case MCLOH_AdrpAddLdr:
case MCLOH_AdrpLdrGotLdr:
case MCLOH_AdrpAddStr:
case MCLOH_AdrpLdrGotStr:
return 3;
}
return -1;
}
/// Store Linker Optimization Hint information (LOH).
class MCLOHDirective {
MCLOHType Kind;
/// Arguments of this directive. Order matters.
SmallVector<MCSymbol *, 3> Args;
/// Emit this directive in \p OutStream using the information available
/// in the given \p ObjWriter and \p Layout to get the address of the
/// arguments within the object file.
void emit_impl(const MCAssembler &Asm, raw_ostream &OutStream,
const MachObjectWriter &ObjWriter) const;
public:
using LOHArgs = SmallVectorImpl<MCSymbol *>;
MCLOHDirective(MCLOHType Kind, const LOHArgs &Args)
: Kind(Kind), Args(Args.begin(), Args.end()) {
assert(isValidMCLOHType(Kind) && "Invalid LOH directive type!");
}
MCLOHType getKind() const { return Kind; }
const LOHArgs &getArgs() const { return Args; }
/// Emit this directive as:
/// <kind, numArgs, addr1, ..., addrN>
void emit(const MCAssembler &Asm, MachObjectWriter &ObjWriter) const;
/// Get the size in bytes of this directive if emitted in \p ObjWriter with
/// the given \p Layout.
uint64_t getEmitSize(const MCAssembler &Asm,
const MachObjectWriter &ObjWriter) const;
};
class MCLOHContainer {
/// Keep track of the emit size of all the LOHs.
mutable uint64_t EmitSize = 0;
/// Keep track of all LOH directives.
SmallVector<MCLOHDirective, 32> Directives;
public:
using LOHDirectives = SmallVectorImpl<MCLOHDirective>;
MCLOHContainer() = default;
/// Const accessor to the directives.
const LOHDirectives &getDirectives() const {
return Directives;
}
/// Add the directive of the given kind \p Kind with the given arguments
/// \p Args to the container.
void addDirective(MCLOHType Kind, const MCLOHDirective::LOHArgs &Args) {
Directives.push_back(MCLOHDirective(Kind, Args));
}
/// Get the size of the directives if emitted.
uint64_t getEmitSize(const MCAssembler &Asm,
const MachObjectWriter &ObjWriter) const {
if (!EmitSize) {
for (const MCLOHDirective &D : Directives)
EmitSize += D.getEmitSize(Asm, ObjWriter);
}
return EmitSize;
}
/// Emit all Linker Optimization Hint in one big table.
/// Each line of the table is emitted by LOHDirective::emit.
void emit(const MCAssembler &Asm, MachObjectWriter &ObjWriter) const {
for (const MCLOHDirective &D : Directives)
D.emit(Asm, ObjWriter);
}
void reset() {
Directives.clear();
EmitSize = 0;
}
};
// Add types for specialized template using MCSymbol.
using MCLOHArgs = MCLOHDirective::LOHArgs;
using MCLOHDirectives = MCLOHContainer::LOHDirectives;
} // end namespace llvm
#endif // LLVM_MC_MCLINKEROPTIMIZATIONHINT_H
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