Add support for the --param ssp-buffer-size= driver option.

PR9673

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162284 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetOptions.h

@@ -155,6 +155,10 @@ namespace llvm {
     /// automatically realigned, if needed.
     unsigned RealignStack : 1;
 
+    /// SSPBufferSize - The minimum size of buffers that will receive stack
+    /// smashing protection when -fstack-protection is used.
+    unsigned SSPBufferSize;
+
     /// EnableFastISel - This flag enables fast-path instruction selection
     /// which trades away generated code quality in favor of reducing
     /// compile time.

lib/CodeGen/StackProtector.cpp

@@ -28,16 +28,10 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetLowering.h"
+#include "llvm/Target/TargetOptions.h"
 #include "llvm/ADT/Triple.h"
 using namespace llvm;
 
-// SSPBufferSize - The lower bound for a buffer to be considered for stack
-// smashing protection.
-static cl::opt<unsigned>
-SSPBufferSize("stack-protector-buffer-size", cl::init(8),
-              cl::desc("Lower bound for a buffer to be considered for "
-                       "stack protection"));
-
 namespace {
   class StackProtector : public FunctionPass {
     /// TLI - Keep a pointer of a TargetLowering to consult for determining
@@ -111,8 +105,8 @@ bool StackProtector::runOnFunction(Function &Fn) {
 bool StackProtector::ContainsProtectableArray(Type *Ty, bool InStruct) const {
   if (!Ty) return false;
   if (ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
+    const TargetMachine &TM = TLI->getTargetMachine();
     if (!AT->getElementType()->isIntegerTy(8)) {
-      const TargetMachine &TM = TLI->getTargetMachine();
       Triple Trip(TM.getTargetTriple());
 
       // If we're on a non-Darwin platform or we're inside of a structure, don't
@@ -123,7 +117,7 @@ bool StackProtector::ContainsProtectableArray(Type *Ty, bool InStruct) const {
 
     // If an array has more than SSPBufferSize bytes of allocated space, then we
     // emit stack protectors.
-    if (SSPBufferSize <= TLI->getTargetData()->getTypeAllocSize(AT))
+    if (TM.Options.SSPBufferSize <= TLI->getTargetData()->getTypeAllocSize(AT))
       return true;
   }
 

tools/llc/llc.cpp

@@ -268,6 +268,11 @@ static cl::opt<std::string> StartAfter("start-after",
   cl::value_desc("pass-name"),
   cl::init(""));
 
+static cl::opt<unsigned>
+SSPBufferSize("stack-protector-buffer-size", cl::init(8),
+              cl::desc("Lower bound for a buffer to be considered for "
+                       "stack protection"));
+
 // GetFileNameRoot - Helper function to get the basename of a filename.
 static inline std::string
 GetFileNameRoot(const std::string &InputFilename) {
@@ -459,6 +464,7 @@ int main(int argc, char **argv) {
   Options.PositionIndependentExecutable = EnablePIE;
   Options.EnableSegmentedStacks = SegmentedStacks;
   Options.UseInitArray = UseInitArray;
+  Options.SSPBufferSize = SSPBufferSize;
 
   std::auto_ptr<TargetMachine>
     target(TheTarget->createTargetMachine(TheTriple.getTriple(),

tools/lto/LTOModule.cpp

@@ -150,6 +150,11 @@ UseInitArray("use-init-array",
   cl::desc("Use .init_array instead of .ctors."),
   cl::init(false));
 
+static cl::opt<unsigned>
+SSPBufferSize("stack-protector-buffer-size", cl::init(8),
+              cl::desc("Lower bound for a buffer to be considered for "
+                       "stack protection"));
+
 LTOModule::LTOModule(llvm::Module *m, llvm::TargetMachine *t)
   : _module(m), _target(t),
     _context(*_target->getMCAsmInfo(), *_target->getRegisterInfo(), NULL),
@@ -252,6 +257,7 @@ void LTOModule::getTargetOptions(TargetOptions &Options) {
   Options.PositionIndependentExecutable = EnablePIE;
   Options.EnableSegmentedStacks = SegmentedStacks;
   Options.UseInitArray = UseInitArray;
+  Options.SSPBufferSize = SSPBufferSize;
 }
 
 LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,