[clang] [llvm] [X86][CodeGen] security check cookie execute only when needed (PR #95904)

[via cfe-commits]

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+//===---- X86FixupBufferSecurityCheck.cpp Fix Buffer Security Check Call---===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// Buffer Security Check implementation inserts platform specific callback into
+// code. For windows __security_check_cookie call gets call everytime function
+// is return without fixup. Since this function is defined in runtime library,
+// it incures cost of call in dll which simply does comparison and returns most
+// time. With Fixup, We selective move to call in DLL only if comparison fails.
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "X86FrameLowering.h"
+#include "X86InstrInfo.h"
+#include "X86Subtarget.h"
+#include "llvm/CodeGen/LivePhysRegs.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/IR/Module.h"
+#include <iterator>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "x86-fixup-bscheck"
+
+namespace {
+
+class X86WinFixupBufferSecurityCheckPass : public MachineFunctionPass {
+public:
+  static char ID;
+
+  X86WinFixupBufferSecurityCheckPass() : MachineFunctionPass(ID) {}
+
+  StringRef getPassName() const override {
+    return "X86 Fixup Buffer Security Check";
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mahesh-attarde wrote:

done.

https://github.com/llvm/llvm-project/pull/95904