X86ReturnThunks.cpp File Reference

Pass that replaces ret instructions with a jmp to __x86_return_thunk. More...

#include "X86.h"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Support/Debug.h"
#include "llvm/TargetParser/Triple.h"

Go to the source code of this file.

Macros
#define	PASS_KEY   "x86-return-thunks"
#define	DEBUG_TYPE   PASS_KEY

Detailed Description

Pass that replaces ret instructions with a jmp to __x86_return_thunk.

This corresponds to -mfunction-return=thunk-extern or attribute((function_return("thunk-extern").

This pass is a minimal implementation necessary to help mitigate RetBleed for the Linux kernel.

Should support for thunk or thunk-inline be necessary in the future, then this pass should be combined with x86-retpoline-thunks which already has machinery to emit thunks. Until then, YAGNI.

This pass is very similar to x86-lvi-ret.

Definition in file X86ReturnThunks.cpp.

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   PASS_KEY

Definition at line 44 of file X86ReturnThunks.cpp.

PASS_KEY

#define PASS_KEY   "x86-return-thunks"

Definition at line 43 of file X86ReturnThunks.cpp.