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-rw-r--r--llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp6
-rw-r--r--llvm/lib/CodeGen/AsmPrinter/WinCFGuard.cpp22
-rw-r--r--llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h9
-rw-r--r--llvm/lib/CodeGen/CFGuardLongjmp.cpp119
-rw-r--r--llvm/lib/CodeGen/CMakeLists.txt1
-rw-r--r--llvm/lib/CodeGen/CodeGen.cpp1
-rw-r--r--llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp8
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/FastISel.cpp2
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp26
9 files changed, 182 insertions, 12 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 73c53d6c4af..3692a03c268 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -139,7 +139,7 @@ static const char *const DbgTimerDescription = "Debug Info Emission";
static const char *const EHTimerName = "write_exception";
static const char *const EHTimerDescription = "DWARF Exception Writer";
static const char *const CFGuardName = "Control Flow Guard";
-static const char *const CFGuardDescription = "Control Flow Guard Tables";
+static const char *const CFGuardDescription = "Control Flow Guard";
static const char *const CodeViewLineTablesGroupName = "linetables";
static const char *const CodeViewLineTablesGroupDescription =
"CodeView Line Tables";
@@ -381,12 +381,12 @@ bool AsmPrinter::doInitialization(Module &M) {
EHTimerDescription, DWARFGroupName,
DWARFGroupDescription);
+ // Emit tables for any value of cfguard flag (i.e. cfguard=1 or cfguard=2).
if (mdconst::extract_or_null<ConstantInt>(
- MMI->getModule()->getModuleFlag("cfguardtable")))
+ MMI->getModule()->getModuleFlag("cfguard")))
Handlers.emplace_back(std::make_unique<WinCFGuard>(this), CFGuardName,
CFGuardDescription, DWARFGroupName,
DWARFGroupDescription);
-
return false;
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.cpp b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.cpp
index 290be81c6ba..f071a2583e5 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.cpp
@@ -6,7 +6,8 @@
//
//===----------------------------------------------------------------------===//
//
-// This file contains support for writing Win64 exception info into asm files.
+// This file contains support for writing the metadata for Windows Control Flow
+// Guard, including address-taken functions, and valid longjmp targets.
//
//===----------------------------------------------------------------------===//
@@ -29,16 +30,33 @@ WinCFGuard::WinCFGuard(AsmPrinter *A) : AsmPrinterHandler(), Asm(A) {}
WinCFGuard::~WinCFGuard() {}
+void WinCFGuard::endFunction(const MachineFunction *MF) {
+
+ // Skip functions without any longjmp targets.
+ if (MF->getLongjmpTargets().empty())
+ return;
+
+ // Copy the function's longjmp targets to a module-level list.
+ LongjmpTargets.insert(LongjmpTargets.end(), MF->getLongjmpTargets().begin(),
+ MF->getLongjmpTargets().end());
+}
+
void WinCFGuard::endModule() {
const Module *M = Asm->MMI->getModule();
std::vector<const Function *> Functions;
for (const Function &F : *M)
if (F.hasAddressTaken())
Functions.push_back(&F);
- if (Functions.empty())
+ if (Functions.empty() && LongjmpTargets.empty())
return;
auto &OS = *Asm->OutStreamer;
OS.SwitchSection(Asm->OutContext.getObjectFileInfo()->getGFIDsSection());
for (const Function *F : Functions)
OS.EmitCOFFSymbolIndex(Asm->getSymbol(F));
+
+ // Emit the symbol index of each longjmp target.
+ OS.SwitchSection(Asm->OutContext.getObjectFileInfo()->getGLJMPSection());
+ for (const MCSymbol *S : LongjmpTargets) {
+ OS.EmitCOFFSymbolIndex(S);
+ }
}
diff --git a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
index def0a59ab00..494a153b05b 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
+++ b/llvm/lib/CodeGen/AsmPrinter/WinCFGuard.h
@@ -6,7 +6,8 @@
//
//===----------------------------------------------------------------------===//
//
-// This file contains support for writing windows exception info into asm files.
+// This file contains support for writing the metadata for Windows Control Flow
+// Guard, including address-taken functions, and valid longjmp targets.
//
//===----------------------------------------------------------------------===//
@@ -15,12 +16,14 @@
#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;
public:
WinCFGuard(AsmPrinter *A);
@@ -28,7 +31,7 @@ public:
void setSymbolSize(const MCSymbol *Sym, uint64_t Size) override {}
- /// Emit the Control Flow Guard function ID table
+ /// Emit the Control Flow Guard function ID table.
void endModule() override;
/// Gather pre-function debug information.
@@ -39,7 +42,7 @@ public:
/// Gather post-function debug information.
/// Please note that some AsmPrinter implementations may not call
/// beginFunction at all.
- void endFunction(const MachineFunction *MF) override {}
+ void endFunction(const MachineFunction *MF) override;
/// Process beginning of an instruction.
void beginInstruction(const MachineInstr *MI) override {}
diff --git a/llvm/lib/CodeGen/CFGuardLongjmp.cpp b/llvm/lib/CodeGen/CFGuardLongjmp.cpp
new file mode 100644
index 00000000000..42ad22b6cfa
--- /dev/null
+++ b/llvm/lib/CodeGen/CFGuardLongjmp.cpp
@@ -0,0 +1,119 @@
+//===-- 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"
+
+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;
+}
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index 50b469d6d93..1d561c3c3e8 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -10,6 +10,7 @@ add_llvm_library(LLVMCodeGen
BuiltinGCs.cpp
CalcSpillWeights.cpp
CallingConvLower.cpp
+ CFGuardLongjmp.cpp
CFIInstrInserter.cpp
CodeGen.cpp
CodeGenPrepare.cpp
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index ad9525f927e..85696ccc482 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -22,6 +22,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
initializeAtomicExpandPass(Registry);
initializeBranchFolderPassPass(Registry);
initializeBranchRelaxationPass(Registry);
+ initializeCFGuardLongjmpPass(Registry);
initializeCFIInstrInserterPass(Registry);
initializeCodeGenPreparePass(Registry);
initializeDeadMachineInstructionElimPass(Registry);
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 45cef4aca88..6e2d22057c1 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -1590,6 +1590,10 @@ bool IRTranslator::translateCall(const User &U, MachineIRBuilder &MIRBuilder) {
if (F && F->hasDLLImportStorageClass())
return false;
+ // FIXME: support control flow guard targets.
+ if (CI.countOperandBundlesOfType(LLVMContext::OB_cfguardtarget))
+ return false;
+
if (CI.isInlineAsm())
return translateInlineAsm(CI, MIRBuilder);
@@ -1683,6 +1687,10 @@ bool IRTranslator::translateInvoke(const User &U,
if (I.countOperandBundlesOfType(LLVMContext::OB_deopt))
return false;
+ // FIXME: support control flow guard targets.
+ if (I.countOperandBundlesOfType(LLVMContext::OB_cfguardtarget))
+ return false;
+
// FIXME: support Windows exception handling.
if (!isa<LandingPadInst>(EHPadBB->front()))
return false;
diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index 6d7260d7aee..4586a20562e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1190,6 +1190,8 @@ bool FastISel::lowerCallTo(CallLoweringInfo &CLI) {
Flags.setSwiftSelf();
if (Arg.IsSwiftError)
Flags.setSwiftError();
+ if (Arg.IsCFGuardTarget)
+ Flags.setCFGuardTarget();
if (Arg.IsByVal)
Flags.setByVal();
if (Arg.IsInAlloca) {
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 51f5b1998bb..e8e2bb49c9e 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -2746,8 +2746,9 @@ void SelectionDAGBuilder::visitInvoke(const InvokeInst &I) {
// Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
// have to do anything here to lower funclet bundles.
- assert(!I.hasOperandBundlesOtherThan(
- {LLVMContext::OB_deopt, LLVMContext::OB_funclet}) &&
+ assert(!I.hasOperandBundlesOtherThan({LLVMContext::OB_deopt,
+ LLVMContext::OB_funclet,
+ LLVMContext::OB_cfguardtarget}) &&
"Cannot lower invokes with arbitrary operand bundles yet!");
const Value *Callee(I.getCalledValue());
@@ -7145,6 +7146,18 @@ void SelectionDAGBuilder::LowerCallTo(ImmutableCallSite CS, SDValue Callee,
isTailCall = false;
}
+ // If call site has a cfguardtarget operand bundle, create and add an
+ // additional ArgListEntry.
+ if (auto Bundle = CS.getOperandBundle(LLVMContext::OB_cfguardtarget)) {
+ TargetLowering::ArgListEntry Entry;
+ Value *V = Bundle->Inputs[0];
+ SDValue ArgNode = getValue(V);
+ Entry.Node = ArgNode;
+ Entry.Ty = V->getType();
+ Entry.IsCFGuardTarget = true;
+ Args.push_back(Entry);
+ }
+
// Check if target-independent constraints permit a tail call here.
// Target-dependent constraints are checked within TLI->LowerCallTo.
if (isTailCall && !isInTailCallPosition(CS, DAG.getTarget()))
@@ -7686,8 +7699,10 @@ void SelectionDAGBuilder::visitCall(const CallInst &I) {
// Deopt bundles are lowered in LowerCallSiteWithDeoptBundle, and we don't
// have to do anything here to lower funclet bundles.
- assert(!I.hasOperandBundlesOtherThan(
- {LLVMContext::OB_deopt, LLVMContext::OB_funclet}) &&
+ // CFGuardTarget bundles are lowered in LowerCallTo.
+ assert(!I.hasOperandBundlesOtherThan({LLVMContext::OB_deopt,
+ LLVMContext::OB_funclet,
+ LLVMContext::OB_cfguardtarget}) &&
"Cannot lower calls with arbitrary operand bundles!");
SDValue Callee = getValue(I.getCalledValue());
@@ -9030,6 +9045,7 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
Entry.IsReturned = false;
Entry.IsSwiftSelf = false;
Entry.IsSwiftError = false;
+ Entry.IsCFGuardTarget = false;
Entry.Alignment = Align;
CLI.getArgs().insert(CLI.getArgs().begin(), Entry);
CLI.NumFixedArgs += 1;
@@ -9142,6 +9158,8 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
Flags.setSwiftSelf();
if (Args[i].IsSwiftError)
Flags.setSwiftError();
+ if (Args[i].IsCFGuardTarget)
+ Flags.setCFGuardTarget();
if (Args[i].IsByVal)
Flags.setByVal();
if (Args[i].IsInAlloca) {
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