mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-19 11:02:59 +02:00
68092989f3
This file lists every pass in LLVM, and is included by Pass.h, which is very popular. Every time we add, remove, or rename a pass in LLVM, it caused lots of recompilation. I found this fact by looking at this table, which is sorted by the number of times a file was changed over the last 100,000 git commits multiplied by the number of object files that depend on it in the current checkout: recompiles touches affected_files header 342380 95 3604 llvm/include/llvm/ADT/STLExtras.h 314730 234 1345 llvm/include/llvm/InitializePasses.h 307036 118 2602 llvm/include/llvm/ADT/APInt.h 213049 59 3611 llvm/include/llvm/Support/MathExtras.h 170422 47 3626 llvm/include/llvm/Support/Compiler.h 162225 45 3605 llvm/include/llvm/ADT/Optional.h 158319 63 2513 llvm/include/llvm/ADT/Triple.h 140322 39 3598 llvm/include/llvm/ADT/StringRef.h 137647 59 2333 llvm/include/llvm/Support/Error.h 131619 73 1803 llvm/include/llvm/Support/FileSystem.h Before this change, touching InitializePasses.h would cause 1345 files to recompile. After this change, touching it only causes 550 compiles in an incremental rebuild. Reviewers: bkramer, asbirlea, bollu, jdoerfert Differential Revision: https://reviews.llvm.org/D70211
121 lines
3.7 KiB
C++
121 lines
3.7 KiB
C++
//===-- CFGuardLongjmp.cpp - Longjmp symbols for CFGuard --------*- 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
///
|
|
/// \file
|
|
/// This file contains a machine function pass to insert a symbol after each
|
|
/// call to _setjmp and store this in the MachineFunction's LongjmpTargets
|
|
/// vector. This will be used to emit the table of valid longjmp targets used
|
|
/// by Control Flow Guard.
|
|
///
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/CodeGen/MachineBasicBlock.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
#include "llvm/CodeGen/MachineInstr.h"
|
|
#include "llvm/CodeGen/MachineModuleInfo.h"
|
|
#include "llvm/CodeGen/MachineOperand.h"
|
|
#include "llvm/CodeGen/Passes.h"
|
|
#include "llvm/InitializePasses.h"
|
|
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "cfguard-longjmp"
|
|
|
|
STATISTIC(CFGuardLongjmpTargets,
|
|
"Number of Control Flow Guard longjmp targets");
|
|
|
|
namespace {
|
|
|
|
/// MachineFunction pass to insert a symbol after each call to _setjmp and store
|
|
/// this in the MachineFunction's LongjmpTargets vector.
|
|
class CFGuardLongjmp : public MachineFunctionPass {
|
|
public:
|
|
static char ID;
|
|
|
|
CFGuardLongjmp() : MachineFunctionPass(ID) {
|
|
initializeCFGuardLongjmpPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
StringRef getPassName() const override {
|
|
return "Control Flow Guard longjmp targets";
|
|
}
|
|
|
|
bool runOnMachineFunction(MachineFunction &MF) override;
|
|
};
|
|
|
|
} // end anonymous namespace
|
|
|
|
char CFGuardLongjmp::ID = 0;
|
|
|
|
INITIALIZE_PASS(CFGuardLongjmp, "CFGuardLongjmp",
|
|
"Insert symbols at valid longjmp targets for /guard:cf", false,
|
|
false)
|
|
FunctionPass *llvm::createCFGuardLongjmpPass() { return new CFGuardLongjmp(); }
|
|
|
|
bool CFGuardLongjmp::runOnMachineFunction(MachineFunction &MF) {
|
|
|
|
// Skip modules for which the cfguard flag is not set.
|
|
if (!MF.getMMI().getModule()->getModuleFlag("cfguard"))
|
|
return false;
|
|
|
|
// Skip functions that do not have calls to _setjmp.
|
|
if (!MF.getFunction().callsFunctionThatReturnsTwice())
|
|
return false;
|
|
|
|
SmallVector<MachineInstr *, 8> SetjmpCalls;
|
|
|
|
// Iterate over all instructions in the function and add calls to functions
|
|
// that return twice to the list of targets.
|
|
for (MachineBasicBlock &MBB : MF) {
|
|
for (MachineInstr &MI : MBB) {
|
|
|
|
// Skip instructions that are not calls.
|
|
if (!MI.isCall() || MI.getNumOperands() < 1)
|
|
continue;
|
|
|
|
// Iterate over operands to find calls to global functions.
|
|
for (MachineOperand &MO : MI.operands()) {
|
|
if (!MO.isGlobal())
|
|
continue;
|
|
|
|
auto *F = dyn_cast<Function>(MO.getGlobal());
|
|
if (!F)
|
|
continue;
|
|
|
|
// If the instruction calls a function that returns twice, add
|
|
// it to the list of targets.
|
|
if (F->hasFnAttribute(Attribute::ReturnsTwice)) {
|
|
SetjmpCalls.push_back(&MI);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (SetjmpCalls.empty())
|
|
return false;
|
|
|
|
unsigned SetjmpNum = 0;
|
|
|
|
// For each possible target, create a new symbol and insert it immediately
|
|
// after the call to setjmp. Add this symbol to the MachineFunction's list
|
|
// of longjmp targets.
|
|
for (MachineInstr *Setjmp : SetjmpCalls) {
|
|
SmallString<128> SymbolName;
|
|
raw_svector_ostream(SymbolName) << "$cfgsj_" << MF.getName() << SetjmpNum++;
|
|
MCSymbol *SjSymbol = MF.getContext().getOrCreateSymbol(SymbolName);
|
|
|
|
Setjmp->setPostInstrSymbol(MF, SjSymbol);
|
|
MF.addLongjmpTarget(SjSymbol);
|
|
CFGuardLongjmpTargets++;
|
|
}
|
|
|
|
return true;
|
|
}
|