From f7fea13c22d5354854e94970682be7526d26fbd6 Mon Sep 17 00:00:00 2001
From: Saleem Abdulrasool <compnerd@compnerd.org>
Date: Fri, 30 Jan 2015 23:29:19 +0000
Subject: [PATCH] CodeGen: create a WindowsARMTargetCodeGenInfo

Create a new TargetCodeGenInfo for Windows on ARM to permit annotating the
functions with stack-probe-size (for /Gs and -mstack-probe-support) for
generating the stack probe necessary for Windows targets.  This will be used by
the backend when lowering the frame to generate the stack probe appropriately.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@227641 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/TargetInfo.cpp                    | 34 +++++++++++++++++++
 .../CodeGen/windows-on-arm-stack-probe-size.c | 28 +++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 test/CodeGen/windows-on-arm-stack-probe-size.c

diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index ebac376d7c..d067821419 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -4462,9 +4462,37 @@ public:
                                               llvm::AttributeSet::FunctionIndex,
                                               B));
   }
+};
+
+class WindowsARMTargetCodeGenInfo : public ARMTargetCodeGenInfo {
+  void addStackProbeSizeTargetAttribute(const Decl *D, llvm::GlobalValue *GV,
+                                        CodeGen::CodeGenModule &CGM) const;
+
+public:
+  WindowsARMTargetCodeGenInfo(CodeGenTypes &CGT, ARMABIInfo::ABIKind K)
+      : ARMTargetCodeGenInfo(CGT, K) {}
 
+  void SetTargetAttributes(const Decl *D, llvm::GlobalValue *GV,
+                           CodeGen::CodeGenModule &CGM) const override;
 };
 
+void WindowsARMTargetCodeGenInfo::addStackProbeSizeTargetAttribute(
+    const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
+  if (!isa<FunctionDecl>(D))
+    return;
+  if (CGM.getCodeGenOpts().StackProbeSize == 4096)
+    return;
+
+  llvm::Function *F = cast<llvm::Function>(GV);
+  F->addFnAttr("stack-probe-size",
+               llvm::utostr(CGM.getCodeGenOpts().StackProbeSize));
+}
+
+void WindowsARMTargetCodeGenInfo::SetTargetAttributes(
+    const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &CGM) const {
+  ARMTargetCodeGenInfo::SetTargetAttributes(D, GV, CGM);
+  addStackProbeSizeTargetAttribute(D, GV, CGM);
+}
 }
 
 void ARMABIInfo::computeInfo(CGFunctionInfo &FI) const {
@@ -7075,6 +7103,12 @@ const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
   case llvm::Triple::thumb:
   case llvm::Triple::thumbeb:
     {
+      if (Triple.getOS() == llvm::Triple::Win32) {
+        TheTargetCodeGenInfo =
+            new WindowsARMTargetCodeGenInfo(Types, ARMABIInfo::AAPCS_VFP);
+        return *TheTargetCodeGenInfo;
+      }
+
       ARMABIInfo::ABIKind Kind = ARMABIInfo::AAPCS;
       if (getTarget().getABI() == "apcs-gnu")
         Kind = ARMABIInfo::APCS;
diff --git a/test/CodeGen/windows-on-arm-stack-probe-size.c b/test/CodeGen/windows-on-arm-stack-probe-size.c
new file mode 100644
index 0000000000..d25e15d8f5
--- /dev/null
+++ b/test/CodeGen/windows-on-arm-stack-probe-size.c
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -triple thumbv7-windows-itanium -mstack-probe-size=8096 -O2 -emit-llvm %s -o - \
+// RUN:     | FileCheck %s -check-prefix CHECK-8096
+
+// RUN: %clang_cc1 -triple thumbv7-windows-itanium -mstack-probe-size=4096 -O2 -emit-llvm %s -o - \
+// RUN:     | FileCheck %s -check-prefix CHECK-4096
+
+// RUN: %clang_cc1 -triple thumbv7-windows-itanium -O2 -emit-llvm %s -o - \
+// RUN:     | FileCheck %s -check-prefix CHECK
+
+__declspec(dllimport) void initialise(signed char buffer[4096]);
+
+__declspec(dllexport) signed char function(unsigned index) {
+  signed char buffer[4096];
+  initialise(buffer);
+  return buffer[index];
+}
+
+// CHECK-8096: attributes #0 = {
+// CHECK-8096: "stack-probe-size"="8096"
+// CHECK-8096: }
+
+// CHECK-4096: attributes #0 = {
+// CHECK-4096-NOT: "stack-probe-size"=
+// CHECK-4096: }
+
+// CHECK: attributes #0 = {
+// CHECK-NOT: "stack-probe-size"=
+// CHECK: }
-- 
2.40.0