[llvm] r284254 - [safestack] Use non-thread-local unsafe stack pointer for Contiki OS
David L Kreitzer via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 14 10:56:00 PDT 2016
Author: dlkreitz
Date: Fri Oct 14 12:56:00 2016
New Revision: 284254
URL: http://llvm.org/viewvc/llvm-project?rev=284254&view=rev
Log:
[safestack] Use non-thread-local unsafe stack pointer for Contiki OS
Patch by Michael LeMay
Differential revision: http://reviews.llvm.org/D19852
Modified:
llvm/trunk/include/llvm/Target/TargetLowering.h
llvm/trunk/lib/CodeGen/SafeStack.cpp
llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/test/Transforms/SafeStack/X86/array.ll
Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=284254&r1=284253&r2=284254&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLowering.h Fri Oct 14 12:56:00 2016
@@ -1114,8 +1114,12 @@ public:
/// Should be used only when getIRStackGuard returns nullptr.
virtual Value *getSSPStackGuardCheck(const Module &M) const;
- /// If the target has a standard location for the unsafe stack pointer,
- /// returns the address of that location. Otherwise, returns nullptr.
+protected:
+ Value *getDefaultSafeStackPointerLocation(IRBuilder<> &IRB,
+ bool UseTLS) const;
+
+public:
+ /// Returns the target-specific address of the unsafe stack pointer.
virtual Value *getSafeStackPointerLocation(IRBuilder<> &IRB) const;
/// Returns true if a cast between SrcAS and DestAS is a noop.
Modified: llvm/trunk/lib/CodeGen/SafeStack.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SafeStack.cpp?rev=284254&r1=284253&r2=284254&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SafeStack.cpp (original)
+++ llvm/trunk/lib/CodeGen/SafeStack.cpp Fri Oct 14 12:56:00 2016
@@ -52,16 +52,6 @@ using namespace llvm::safestack;
#define DEBUG_TYPE "safestack"
-enum UnsafeStackPtrStorageVal { ThreadLocalUSP, SingleThreadUSP };
-
-static cl::opt<UnsafeStackPtrStorageVal> USPStorage("safe-stack-usp-storage",
- cl::Hidden, cl::init(ThreadLocalUSP),
- cl::desc("Type of storage for the unsafe stack pointer"),
- cl::values(clEnumValN(ThreadLocalUSP, "thread-local",
- "Thread-local storage"),
- clEnumValN(SingleThreadUSP, "single-thread",
- "Non-thread-local storage")));
-
namespace llvm {
STATISTIC(NumFunctions, "Total number of functions");
@@ -123,9 +113,6 @@ class SafeStack : public FunctionPass {
/// might expect to appear on the stack on most common targets.
enum { StackAlignment = 16 };
- /// \brief Build a value representing a pointer to the unsafe stack pointer.
- Value *getOrCreateUnsafeStackPtr(IRBuilder<> &IRB, Function &F);
-
/// \brief Return the value of the stack canary.
Value *getStackGuard(IRBuilder<> &IRB, Function &F);
@@ -355,41 +342,6 @@ bool SafeStack::IsSafeStackAlloca(const
return true;
}
-Value *SafeStack::getOrCreateUnsafeStackPtr(IRBuilder<> &IRB, Function &F) {
- // Check if there is a target-specific location for the unsafe stack pointer.
- if (Value *V = TL->getSafeStackPointerLocation(IRB))
- return V;
-
- // Otherwise, assume the target links with compiler-rt, which provides a
- // thread-local variable with a magic name.
- Module &M = *F.getParent();
- const char *UnsafeStackPtrVar = "__safestack_unsafe_stack_ptr";
- auto UnsafeStackPtr =
- dyn_cast_or_null<GlobalVariable>(M.getNamedValue(UnsafeStackPtrVar));
-
- bool UseTLS = USPStorage == ThreadLocalUSP;
-
- if (!UnsafeStackPtr) {
- auto TLSModel = UseTLS ?
- GlobalValue::InitialExecTLSModel :
- GlobalValue::NotThreadLocal;
- // 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(
- M, StackPtrTy, false, GlobalValue::ExternalLinkage, nullptr,
- UnsafeStackPtrVar, nullptr, TLSModel);
- } else {
- // The variable exists, check its type and attributes.
- if (UnsafeStackPtr->getValueType() != StackPtrTy)
- report_fatal_error(Twine(UnsafeStackPtrVar) + " must have void* type");
- if (UseTLS != UnsafeStackPtr->isThreadLocal())
- report_fatal_error(Twine(UnsafeStackPtrVar) + " must " +
- (UseTLS ? "" : "not ") + "be thread-local");
- }
- return UnsafeStackPtr;
-}
-
Value *SafeStack::getStackGuard(IRBuilder<> &IRB, Function &F) {
Value *StackGuardVar = TL->getIRStackGuard(IRB);
if (!StackGuardVar)
@@ -784,7 +736,7 @@ bool SafeStack::runOnFunction(Function &
++NumUnsafeStackRestorePointsFunctions;
IRBuilder<> IRB(&F.front(), F.begin()->getFirstInsertionPt());
- UnsafeStackPtr = getOrCreateUnsafeStackPtr(IRB, F);
+ UnsafeStackPtr = TL->getSafeStackPointerLocation(IRB);
// Load the current stack pointer (we'll also use it as a base pointer).
// FIXME: use a dedicated register for it ?
Modified: llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp?rev=284254&r1=284253&r2=284254&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp Fri Oct 14 12:56:00 2016
@@ -1767,9 +1767,41 @@ TargetLoweringBase::getTypeLegalizationC
}
}
+Value *TargetLoweringBase::getDefaultSafeStackPointerLocation(IRBuilder<> &IRB,
+ bool UseTLS) const {
+ // compiler-rt provides a variable with a magic name. Targets that do not
+ // link with compiler-rt may also provide such a variable.
+ Module *M = IRB.GetInsertBlock()->getParent()->getParent();
+ const char *UnsafeStackPtrVar = "__safestack_unsafe_stack_ptr";
+ auto UnsafeStackPtr =
+ dyn_cast_or_null<GlobalVariable>(M->getNamedValue(UnsafeStackPtrVar));
+
+ Type *StackPtrTy = Type::getInt8PtrTy(M->getContext());
+
+ if (!UnsafeStackPtr) {
+ auto TLSModel = UseTLS ?
+ GlobalValue::InitialExecTLSModel :
+ GlobalValue::NotThreadLocal;
+ // 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(
+ *M, StackPtrTy, false, GlobalValue::ExternalLinkage, nullptr,
+ UnsafeStackPtrVar, nullptr, TLSModel);
+ } else {
+ // The variable exists, check its type and attributes.
+ if (UnsafeStackPtr->getValueType() != StackPtrTy)
+ report_fatal_error(Twine(UnsafeStackPtrVar) + " must have void* type");
+ if (UseTLS != UnsafeStackPtr->isThreadLocal())
+ report_fatal_error(Twine(UnsafeStackPtrVar) + " must " +
+ (UseTLS ? "" : "not ") + "be thread-local");
+ }
+ return UnsafeStackPtr;
+}
+
Value *TargetLoweringBase::getSafeStackPointerLocation(IRBuilder<> &IRB) const {
if (!TM.getTargetTriple().isAndroid())
- return nullptr;
+ return getDefaultSafeStackPointerLocation(IRB, true);
// Android provides a libc function to retrieve the address of the current
// thread's unsafe stack pointer.
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=284254&r1=284253&r2=284254&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Oct 14 12:56:00 2016
@@ -2045,6 +2045,9 @@ Value *X86TargetLowering::getSSPStackGua
}
Value *X86TargetLowering::getSafeStackPointerLocation(IRBuilder<> &IRB) const {
+ if (Subtarget.getTargetTriple().isOSContiki())
+ return getDefaultSafeStackPointerLocation(IRB, false);
+
if (!Subtarget.isTargetAndroid())
return TargetLowering::getSafeStackPointerLocation(IRB);
Modified: llvm/trunk/test/Transforms/SafeStack/X86/array.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SafeStack/X86/array.ll?rev=284254&r1=284253&r2=284254&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SafeStack/X86/array.ll (original)
+++ llvm/trunk/test/Transforms/SafeStack/X86/array.ll Fri Oct 14 12:56:00 2016
@@ -1,7 +1,6 @@
; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
-; RUN: opt -safe-stack -safe-stack-usp-storage=single-thread -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
+; RUN: opt -safe-stack -S -mtriple=i386-pc-contiki-unknown < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
-; RUN: opt -safe-stack -safe-stack-usp-storage=single-thread -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SINGLE-THREAD %s
; array [4 x i8]
; Requires protector.
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