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-rw-r--r--llvm/lib/Transforms/Instrumentation/SafeStack.cpp109
1 files changed, 39 insertions, 70 deletions
diff --git a/llvm/lib/Transforms/Instrumentation/SafeStack.cpp b/llvm/lib/Transforms/Instrumentation/SafeStack.cpp
index 6e5e85f0825..fdf96cc130a 100644
--- a/llvm/lib/Transforms/Instrumentation/SafeStack.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SafeStack.cpp
@@ -19,7 +19,6 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
@@ -37,8 +36,6 @@
#include "llvm/Support/Format.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/raw_os_ostream.h"
-#include "llvm/Target/TargetLowering.h"
-#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
@@ -46,9 +43,6 @@ using namespace llvm;
#define DEBUG_TYPE "safestack"
-static const char *const kUnsafeStackPtrVar = "__safestack_unsafe_stack_ptr";
-static const char *const kUnsafeStackPtrAddrFn = "__safestack_pointer_address";
-
namespace llvm {
STATISTIC(NumFunctions, "Total number of functions");
@@ -163,8 +157,6 @@ bool IsSafeStackAlloca(const AllocaInst *AI) {
/// (as determined statically), and the unsafe stack, which contains all
/// local variables that are accessed in unsafe ways.
class SafeStack : public FunctionPass {
- const TargetMachine *TM;
- const TargetLoweringBase *TLI;
const DataLayout *DL;
Type *StackPtrTy;
@@ -172,7 +164,7 @@ class SafeStack : public FunctionPass {
Type *Int32Ty;
Type *Int8Ty;
- Value *UnsafeStackPtr = nullptr;
+ Constant *UnsafeStackPtr = nullptr;
/// Unsafe stack alignment. Each stack frame must ensure that the stack is
/// aligned to this value. We need to re-align the unsafe stack if the
@@ -184,7 +176,7 @@ class SafeStack : public FunctionPass {
/// \brief Build a constant representing a pointer to the unsafe stack
/// pointer.
- Value *getOrCreateUnsafeStackPtr(IRBuilder<> &IRB, Function &F);
+ Constant *getOrCreateUnsafeStackPtr(Module &M);
/// \brief Find all static allocas, dynamic allocas, return instructions and
/// stack restore points (exception unwind blocks and setjmp calls) in the
@@ -200,7 +192,7 @@ class SafeStack : public FunctionPass {
///
/// \returns A pointer to the top of the unsafe stack after all unsafe static
/// allocas are allocated.
- Value *moveStaticAllocasToUnsafeStack(IRBuilder<> &IRB, Function &F,
+ Value *moveStaticAllocasToUnsafeStack(Function &F,
ArrayRef<AllocaInst *> StaticAllocas,
ArrayRef<ReturnInst *> Returns);
@@ -223,11 +215,9 @@ class SafeStack : public FunctionPass {
public:
static char ID; // Pass identification, replacement for typeid.
- SafeStack(const TargetMachine *TM)
- : FunctionPass(ID), TM(TM), TLI(nullptr), DL(nullptr) {
+ SafeStack() : FunctionPass(ID), DL(nullptr) {
initializeSafeStackPass(*PassRegistry::getPassRegistry());
}
- SafeStack() : SafeStack(nullptr) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<AAResultsWrapperPass>();
@@ -247,53 +237,35 @@ public:
bool runOnFunction(Function &F) override;
}; // class SafeStack
-Value *SafeStack::getOrCreateUnsafeStackPtr(IRBuilder<> &IRB, Function &F) {
- Module &M = *F.getParent();
- Triple TargetTriple(M.getTargetTriple());
-
- unsigned Offset;
- unsigned AddressSpace;
- // Check if the target keeps the unsafe stack pointer at a fixed offset.
- if (TLI->getSafeStackPointerLocation(Offset, AddressSpace)) {
- Constant *OffsetVal =
- ConstantInt::get(Type::getInt32Ty(F.getContext()), Offset);
- return ConstantExpr::getIntToPtr(OffsetVal,
- StackPtrTy->getPointerTo(AddressSpace));
- }
-
- // Android provides a libc function that returns the stack pointer address.
- if (TargetTriple.getEnvironment() == llvm::Triple::Android) {
- Value *Fn = M.getOrInsertFunction(kUnsafeStackPtrAddrFn,
- StackPtrTy->getPointerTo(0), nullptr);
- return IRB.CreateCall(Fn);
+Constant *SafeStack::getOrCreateUnsafeStackPtr(Module &M) {
+ // The unsafe stack pointer is stored in a global variable with a magic name.
+ const char *kUnsafeStackPtrVar = "__safestack_unsafe_stack_ptr";
+
+ auto UnsafeStackPtr =
+ dyn_cast_or_null<GlobalVariable>(M.getNamedValue(kUnsafeStackPtrVar));
+
+ if (!UnsafeStackPtr) {
+ // The global variable is not defined yet, define it ourselves.
+ // We use the initial-exec TLS model because we do not support the variable
+ // living anywhere other than in the main executable.
+ UnsafeStackPtr = new GlobalVariable(
+ /*Module=*/M, /*Type=*/StackPtrTy,
+ /*isConstant=*/false, /*Linkage=*/GlobalValue::ExternalLinkage,
+ /*Initializer=*/0, /*Name=*/kUnsafeStackPtrVar,
+ /*InsertBefore=*/nullptr,
+ /*ThreadLocalMode=*/GlobalValue::InitialExecTLSModel);
} else {
- // Otherwise, declare a thread-local variable with a magic name.
- auto UnsafeStackPtr =
- dyn_cast_or_null<GlobalVariable>(M.getNamedValue(kUnsafeStackPtrVar));
-
- if (!UnsafeStackPtr) {
- // The global variable is not defined yet, define it ourselves.
- // We use the initial-exec TLS model because we do not support the
- // variable
- // living anywhere other than in the main executable.
- UnsafeStackPtr = new GlobalVariable(
- /*Module=*/M, /*Type=*/StackPtrTy,
- /*isConstant=*/false, /*Linkage=*/GlobalValue::ExternalLinkage,
- /*Initializer=*/0, /*Name=*/kUnsafeStackPtrVar,
- /*InsertBefore=*/nullptr,
- /*ThreadLocalMode=*/GlobalValue::InitialExecTLSModel);
- } else {
- // The variable exists, check its type and attributes.
- if (UnsafeStackPtr->getValueType() != StackPtrTy) {
- report_fatal_error(Twine(kUnsafeStackPtrVar) + " must have void* type");
- }
+ // The variable exists, check its type and attributes.
+ if (UnsafeStackPtr->getValueType() != StackPtrTy) {
+ report_fatal_error(Twine(kUnsafeStackPtrVar) + " must have void* type");
+ }
- if (!UnsafeStackPtr->isThreadLocal()) {
- report_fatal_error(Twine(kUnsafeStackPtrVar) + " must be thread-local");
- }
+ if (!UnsafeStackPtr->isThreadLocal()) {
+ report_fatal_error(Twine(kUnsafeStackPtrVar) + " must be thread-local");
}
- return UnsafeStackPtr;
}
+
+ return UnsafeStackPtr;
}
void SafeStack::findInsts(Function &F,
@@ -377,12 +349,13 @@ SafeStack::createStackRestorePoints(Function &F,
}
Value *
-SafeStack::moveStaticAllocasToUnsafeStack(IRBuilder<> &IRB, Function &F,
+SafeStack::moveStaticAllocasToUnsafeStack(Function &F,
ArrayRef<AllocaInst *> StaticAllocas,
ArrayRef<ReturnInst *> Returns) {
if (StaticAllocas.empty())
return nullptr;
+ IRBuilder<> IRB(F.getEntryBlock().getFirstInsertionPt());
DIBuilder DIB(*F.getParent());
// We explicitly compute and set the unsafe stack layout for all unsafe
@@ -540,8 +513,6 @@ void SafeStack::moveDynamicAllocasToUnsafeStack(
bool SafeStack::runOnFunction(Function &F) {
auto AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
- TLI = TM->getSubtargetImpl(F)->getTargetLowering();
-
DEBUG(dbgs() << "[SafeStack] Function: " << F.getName() << "\n");
if (!F.hasFnAttribute(Attribute::SafeStack)) {
@@ -601,11 +572,11 @@ bool SafeStack::runOnFunction(Function &F) {
if (!StackRestorePoints.empty())
++NumUnsafeStackRestorePointsFunctions;
- IRBuilder<> IRB(F.begin()->getFirstInsertionPt());
- UnsafeStackPtr = getOrCreateUnsafeStackPtr(IRB, F);
+ if (!UnsafeStackPtr)
+ UnsafeStackPtr = getOrCreateUnsafeStackPtr(*F.getParent());
// The top of the unsafe stack after all unsafe static allocas are allocated.
- Value *StaticTop = moveStaticAllocasToUnsafeStack(IRB, F, StaticAllocas, Returns);
+ Value *StaticTop = moveStaticAllocasToUnsafeStack(F, StaticAllocas, Returns);
// Safe stack object that stores the current unsafe stack top. It is updated
// as unsafe dynamic (non-constant-sized) allocas are allocated and freed.
@@ -627,11 +598,9 @@ bool SafeStack::runOnFunction(Function &F) {
} // end anonymous namespace
char SafeStack::ID = 0;
-INITIALIZE_TM_PASS_BEGIN(SafeStack, "safe-stack",
- "Safe Stack instrumentation pass", false, false)
-INITIALIZE_TM_PASS_END(SafeStack, "safe-stack",
- "Safe Stack instrumentation pass", false, false)
+INITIALIZE_PASS_BEGIN(SafeStack, "safe-stack",
+ "Safe Stack instrumentation pass", false, false)
+INITIALIZE_PASS_END(SafeStack, "safe-stack", "Safe Stack instrumentation pass",
+ false, false)
-FunctionPass *llvm::createSafeStackPass(const llvm::TargetMachine *TM) {
- return new SafeStack(TM);
-}
+FunctionPass *llvm::createSafeStackPass() { return new SafeStack(); }
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