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llvm-mirror/lib/CodeGen/AsmPrinter/WinCFGuard.h
Andrew Paverd adbf373fb6 [CFGuard] Add address-taken IAT tables and delay-load support
This patch adds support for creating Guard Address-Taken IAT Entry Tables (.giats$y sections) in object files, matching the behavior of MSVC. These contain lists of address-taken imported functions, which are used by the linker to create the final GIATS table.
Additionally, if any DLLs are delay-loaded, the linker must look through the .giats tables and add the respective load thunks of address-taken imports to the GFIDS table, as these are also valid call targets.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D87544
2020-11-17 18:24:45 -08:00

58 lines
1.8 KiB
C++

//===-- WinCFGuard.h - Windows Control Flow Guard Handling ----*- 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 contains support for writing the metadata for Windows Control Flow
// Guard, including address-taken functions, and valid longjmp targets.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WINCFGUARD_H
#define LLVM_LIB_CODEGEN_ASMPRINTER_WINCFGUARD_H
#include "llvm/CodeGen/AsmPrinterHandler.h"
#include "llvm/Support/Compiler.h"
#include <vector>
namespace llvm {
class LLVM_LIBRARY_VISIBILITY WinCFGuard : public AsmPrinterHandler {
/// Target of directive emission.
AsmPrinter *Asm;
std::vector<const MCSymbol *> LongjmpTargets;
MCSymbol *lookupImpSymbol(const MCSymbol *Sym);
public:
WinCFGuard(AsmPrinter *A);
~WinCFGuard() override;
void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
/// Emit the Control Flow Guard function ID table.
void endModule() override;
/// Gather pre-function debug information.
/// Every beginFunction(MF) call should be followed by an endFunction(MF)
/// call.
void beginFunction(const MachineFunction *MF) override {}
/// Gather post-function debug information.
/// Please note that some AsmPrinter implementations may not call
/// beginFunction at all.
void endFunction(const MachineFunction *MF) override;
/// Process beginning of an instruction.
void beginInstruction(const MachineInstr *MI) override {}
/// Process end of an instruction.
void endInstruction() override {}
};
} // namespace llvm
#endif