Fix up -fstack-protector on linux to use the segment

registers.  Split out testcases per architecture and os
now.

Patch from Nelson Elhage.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107640 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetLowering.h

@@ -749,6 +749,14 @@ public:
   /// getFunctionAlignment - Return the Log2 alignment of this function.
   virtual unsigned getFunctionAlignment(const Function *) const = 0;
 
+  /// getStackCookieLocation - Return true if the target stores stack
+  /// protector cookies at a fixed offset in some non-standard address
+  /// space, and populates the address space and offset as
+  /// appropriate.
+  virtual bool getStackCookieLocation(unsigned &AddressSpace, unsigned &Offset) const {
+    return false;
+  }
+
   //===--------------------------------------------------------------------===//
   // TargetLowering Optimization Methods
   //

lib/CodeGen/StackProtector.cpp

@@ -136,7 +136,7 @@ bool StackProtector::RequiresStackProtector() const {
 bool StackProtector::InsertStackProtectors() {
   BasicBlock *FailBB = 0;       // The basic block to jump to if check fails.
   AllocaInst *AI = 0;           // Place on stack that stores the stack guard.
-  Constant *StackGuardVar = 0;  // The stack guard variable.
+  Value *StackGuardVar = 0;  // The stack guard variable.
 
   for (Function::iterator I = F->begin(), E = F->end(); I != E; ) {
     BasicBlock *BB = I++;
@@ -155,7 +155,20 @@ bool StackProtector::InsertStackProtectors() {
       // 
       PointerType *PtrTy = PointerType::getUnqual(
           Type::getInt8Ty(RI->getContext()));
-      StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy);
+
+      unsigned AddressSpace, Offset;
+      if (TLI->getStackCookieLocation(AddressSpace, Offset)) {
+        Constant *ASPtr = Constant::getNullValue(
+            PointerType::get(Type::getInt8Ty(RI->getContext()), AddressSpace));
+        APInt OffsetInt(32, Offset);
+        Constant *OffsetVal = Constant::getIntegerValue(
+            Type::getInt32Ty(RI->getContext()), OffsetInt);
+        StackGuardVar = ConstantExpr::getPointerCast(
+            ConstantExpr::getGetElementPtr(ASPtr, &OffsetVal, 1),
+            PointerType::get(PtrTy, AddressSpace));
+      } else {
+          StackGuardVar = M->getOrInsertGlobal("__stack_chk_guard", PtrTy); 
+      }
 
       BasicBlock &Entry = F->getEntryBlock();
       Instruction *InsPt = &Entry.front();

lib/Target/X86/X86ISelLowering.cpp

@@ -1189,6 +1189,27 @@ unsigned X86TargetLowering::getFunctionAlignment(const Function *F) const {
   return F->hasFnAttr(Attribute::OptimizeForSize) ? 0 : 4;
 }
 
+bool X86TargetLowering::getStackCookieLocation(unsigned &AddressSpace,
+                                               unsigned &Offset) const {
+  if (!Subtarget->isTargetLinux())
+    return false;
+
+  if (Subtarget->is64Bit()) {
+    // %fs:0x28, unless we're using a Kernel code model, in which case it's %gs:
+    Offset = 0x28;
+    if (getTargetMachine().getCodeModel() == CodeModel::Kernel)
+      AddressSpace = 256;
+    else
+      AddressSpace = 257;
+  } else {
+    // %gs:0x14 on i386
+    Offset = 0x14;
+    AddressSpace = 256;
+  }
+  return true;
+}
+
+
 //===----------------------------------------------------------------------===//
 //               Return Value Calling Convention Implementation
 //===----------------------------------------------------------------------===//

lib/Target/X86/X86ISelLowering.h

@@ -593,6 +593,12 @@ namespace llvm {
     /// getFunctionAlignment - Return the Log2 alignment of this function.
     virtual unsigned getFunctionAlignment(const Function *F) const;
 
+    /// getStackCookieLocation - Return true if the target stores stack
+    /// protector cookies at a fixed offset in some non-standard address
+    /// space, and populates the address space and offset as
+    /// appropriate.
+    virtual bool getStackCookieLocation(unsigned &AddressSpace, unsigned &Offset) const;
+
   private:
     /// Subtarget - Keep a pointer to the X86Subtarget around so that we can
     /// make the right decision when generating code for different targets.

test/CodeGen/PowerPC/stack-protector.ll

@@ -0,0 +1,25 @@
+; RUN: llc -march=ppc32 < %s -o - | grep {__stack_chk_guard}
+; RUN: llc -march=ppc32 < %s -o - | grep {__stack_chk_fail}
+
+@"\01LC" = internal constant [11 x i8] c"buf == %s\0A\00"		; <[11 x i8]*> [#uses=1]
+
+define void @test(i8* %a) nounwind ssp {
+entry:
+	%a_addr = alloca i8*		; <i8**> [#uses=2]
+	%buf = alloca [8 x i8]		; <[8 x i8]*> [#uses=2]
+  %"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
+	store i8* %a, i8** %a_addr
+	%buf1 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
+	%0 = load i8** %a_addr, align 4		; <i8*> [#uses=1]
+	%1 = call i8* @strcpy(i8* %buf1, i8* %0) nounwind		; <i8*> [#uses=0]
+  %buf2 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
+	%2 = call i32 (i8*, ...)* @printf(i8* getelementptr ([11 x i8]* @"\01LC", i32 0, i32 0), i8* %buf2) nounwind		; <i32> [#uses=0]
+	br label %return
+
+return:		; preds = %entry
+	ret void
+}
+
+declare i8* @strcpy(i8*, i8*) nounwind
+
+declare i32 @printf(i8*, ...) nounwind

test/CodeGen/X86/stack-protector-linux.ll

@@ -0,0 +1,28 @@
+; RUN: llc -mtriple=i386-pc-linux-gnu < %s -o - | grep %gs:
+; RUN: llc -mtriple=x86_64-pc-linux-gnu < %s -o - | grep %fs:
+; RUN: llc -code-model=kernel -mtriple=x86_64-pc-linux-gnu < %s -o - | grep %gs:
+; RUN: llc -mtriple=x86_64-apple-darwin < %s -o - | grep {__stack_chk_guard}
+; RUN: llc -mtriple=x86_64-apple-darwin < %s -o - | grep {__stack_chk_fail}
+
+@"\01LC" = internal constant [11 x i8] c"buf == %s\0A\00"		; <[11 x i8]*> [#uses=1]
+
+define void @test(i8* %a) nounwind ssp {
+entry:
+	%a_addr = alloca i8*		; <i8**> [#uses=2]
+	%buf = alloca [8 x i8]		; <[8 x i8]*> [#uses=2]
+	%"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
+	store i8* %a, i8** %a_addr
+	%buf1 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
+	%0 = load i8** %a_addr, align 4		; <i8*> [#uses=1]
+	%1 = call i8* @strcpy(i8* %buf1, i8* %0) nounwind		; <i8*> [#uses=0]
+	%buf2 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
+	%2 = call i32 (i8*, ...)* @printf(i8* getelementptr ([11 x i8]* @"\01LC", i32 0, i32 0), i8* %buf2) nounwind		; <i32> [#uses=0]
+	br label %return
+
+return:		; preds = %entry
+	ret void
+}
+
+declare i8* @strcpy(i8*, i8*) nounwind
+
+declare i32 @printf(i8*, ...) nounwind

test/CodeGen/X86/stack-protector.ll

@@ -1,5 +1,5 @@
-; RUN: llc < %s -o - | grep {__stack_chk_guard}
+; RUN: llc -march=x86 < %s -o - | grep {__stack_chk_guard}
-; RUN: llc < %s -o - | grep {__stack_chk_fail}
+; RUN: llc -march=x86 < %s -o - | grep {__stack_chk_fail}
 
 @"\01LC" = internal constant [11 x i8] c"buf == %s\0A\00"		; <[11 x i8]*> [#uses=1]
 
@@ -7,12 +7,12 @@ define void @test(i8* %a) nounwind ssp {
 entry:
 	%a_addr = alloca i8*		; <i8**> [#uses=2]
 	%buf = alloca [8 x i8]		; <[8 x i8]*> [#uses=2]
-	%"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
+  %"alloca point" = bitcast i32 0 to i32		; <i32> [#uses=0]
 	store i8* %a, i8** %a_addr
 	%buf1 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
 	%0 = load i8** %a_addr, align 4		; <i8*> [#uses=1]
 	%1 = call i8* @strcpy(i8* %buf1, i8* %0) nounwind		; <i8*> [#uses=0]
-	%buf2 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
+  %buf2 = bitcast [8 x i8]* %buf to i8*		; <i8*> [#uses=1]
 	%2 = call i32 (i8*, ...)* @printf(i8* getelementptr ([11 x i8]* @"\01LC", i32 0, i32 0), i8* %buf2) nounwind		; <i32> [#uses=0]
 	br label %return