[PATCH] D102742: [IR] make stack-protector-guard-* flags into module attrs

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers created this revision.
nickdesaulniers added reviewers: MaskRay, pcc, xiangzhangllvm.
Herald added subscribers: dexonsmith, hiraditya, kristof.beyls.
nickdesaulniers requested review of this revision.
Herald added projects: clang, LLVM.
Herald added subscribers: llvm-commits, cfe-commits.

D88631 <https://reviews.llvm.org/D88631> added initial support for:

- -mstack-protector-guard=
- -mstack-protector-guard-reg=
- -mstack-protector-guard-offset=

flags, and D100919 <https://reviews.llvm.org/D100919> extended these to 
AArch64. Unfortunately, these flags
aren't retained for LTO. Make them module attributes rather than
TargetOptions.

Link: https://github.com/ClangBuiltLinux/linux/issues/1378


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D102742

Files:
  clang/lib/CodeGen/CodeGenModule.cpp
  llvm/include/llvm/IR/Module.h
  llvm/lib/IR/Module.cpp
  llvm/lib/Target/AArch64/AArch64InstrInfo.cpp


Index: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1904,10 +1904,10 @@
   }
 
   Register Reg = MI.getOperand(0).getReg();
-  TargetOptions Options = MI.getParent()->getParent()->getTarget().Options;
-  if (Options.StackProtectorGuard == StackProtectorGuards::SysReg) {
+  Module &M = *MBB.getParent()->getFunction().getParent();
+  if (M.getStackProtectorGuard() == "sysreg") {
     const AArch64SysReg::SysReg *SrcReg =
-        AArch64SysReg::lookupSysRegByName(Options.StackProtectorGuardReg);
+        AArch64SysReg::lookupSysRegByName(M.getStackProtectorGuardReg());
     if (!SrcReg)
       report_fatal_error("Unknown SysReg for Stack Protector Guard Register");
 
@@ -1915,7 +1915,7 @@
     BuildMI(MBB, MI, DL, get(AArch64::MRS))
         .addDef(Reg, RegState::Renamable)
         .addImm(SrcReg->Encoding);
-    int Offset = Options.StackProtectorGuardOffset;
+    int Offset = M.getStackProtectorGuardOffset();
     if (Offset >= 0 && Offset <= 32760 && Offset % 8 == 0) {
       // ldr xN, [xN, #offset]
       BuildMI(MBB, MI, DL, get(AArch64::LDRXui))
Index: llvm/lib/IR/Module.cpp
===================================================================
--- llvm/lib/IR/Module.cpp
+++ llvm/lib/IR/Module.cpp
@@ -686,6 +686,42 @@
   addModuleFlag(ModFlagBehavior::Max, "frame-pointer", static_cast<int>(Kind));
 }
 
+StringRef Module::getStackProtectorGuard() const {
+  Metadata *MD = getModuleFlag("stack-protector-guard");
+  if (auto *MDS = dyn_cast_or_null<MDString>(MD))
+    return MDS->getString();
+  return {};
+}
+
+void Module::setStackProtectorGuard(StringRef Kind) {
+  MDString *ID = MDString::get(getContext(), Kind);
+  addModuleFlag(ModFlagBehavior::Warning, "stack-protector-guard", ID);
+}
+
+StringRef Module::getStackProtectorGuardReg() const {
+  Metadata *MD = getModuleFlag("stack-protector-guard-reg");
+  if (auto *MDS = dyn_cast_or_null<MDString>(MD))
+    return MDS->getString();
+  return {};
+}
+
+void Module::setStackProtectorGuardReg(StringRef Reg) {
+  MDString *ID = MDString::get(getContext(), Reg);
+  addModuleFlag(ModFlagBehavior::Warning, "stack-protector-guard-reg", ID);
+}
+
+int Module::getStackProtectorGuardOffset() const {
+  Metadata *MD = getModuleFlag("stack-protector-guard-offset");
+  if (auto *CI = mdconst::dyn_extract_or_null<ConstantInt>(MD))
+    return CI->getSExtValue();
+  return 0;
+}
+
+void Module::setStackProtectorGuardOffset(int offset) {
+  addModuleFlag(ModFlagBehavior::Warning, "stack-protector-guard-offset",
+                offset);
+}
+
 void Module::setSDKVersion(const VersionTuple &V) {
   SmallVector<unsigned, 3> Entries;
   Entries.push_back(V.getMajor());
Index: llvm/include/llvm/IR/Module.h
===================================================================
--- llvm/include/llvm/IR/Module.h
+++ llvm/include/llvm/IR/Module.h
@@ -895,6 +895,14 @@
   FramePointerKind getFramePointer() const;
   void setFramePointer(FramePointerKind Kind);
 
+  // enum class StackProtectorGuards { None, TLS, Global, SysReg };
+  StringRef getStackProtectorGuard() const;
+  void setStackProtectorGuard(StringRef Kind);
+  StringRef getStackProtectorGuardReg() const;
+  void setStackProtectorGuardReg(StringRef Reg);
+  int getStackProtectorGuardOffset() const;
+  void setStackProtectorGuardOffset(int offset);
+
   /// @name Utility functions for querying and setting the build SDK version
   /// @{
 
Index: clang/lib/CodeGen/CodeGenModule.cpp
===================================================================
--- clang/lib/CodeGen/CodeGenModule.cpp
+++ clang/lib/CodeGen/CodeGenModule.cpp
@@ -773,6 +773,15 @@
   if (!getCodeGenOpts().RecordCommandLine.empty())
     EmitCommandLineMetadata();
 
+  if (getCodeGenOpts().StackProtectorGuard != "")
+    getModule().setStackProtectorGuard(getCodeGenOpts().StackProtectorGuard);
+  if (getCodeGenOpts().StackProtectorGuardReg != "none")
+    getModule().setStackProtectorGuardReg(
+        getCodeGenOpts().StackProtectorGuardReg);
+  if (getCodeGenOpts().StackProtectorGuardOffset != INT_MAX)
+    getModule().setStackProtectorGuardOffset(
+        getCodeGenOpts().StackProtectorGuardOffset);
+
   getTargetCodeGenInfo().emitTargetMetadata(*this, MangledDeclNames);
 
   EmitBackendOptionsMetadata(getCodeGenOpts());

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