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

D88631 added initial support for:

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

flags, and 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

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D102742

include/llvm/CodeGen/CommandFlags.h

@@ -106,10 +106,6 @@ bool getXCOFFTracebackTable();
 
 std::string getBBSections();
 
-std::string getStackProtectorGuard();
-int getStackProtectorGuardOffset();
-std::string getStackProtectorGuardReg();
-
 unsigned getTLSSize();
 
 bool getEmulatedTLS();
@@ -150,9 +146,6 @@ struct RegisterCodeGenFlags {
 
 llvm::BasicBlockSection getBBSectionsMode(llvm::TargetOptions &Options);
 
-llvm::StackProtectorGuards
-getStackProtectorGuardMode(llvm::TargetOptions &Options);
-
 /// Common utility function tightly tied to the options listed here. Initializes
 /// a TargetOptions object with CodeGen flags and returns it.
 /// \p TheTriple is used to determine the default value for options if

include/llvm/IR/Module.h

@@ -895,6 +895,20 @@ public:
   FramePointerKind getFramePointer() const;
   void setFramePointer(FramePointerKind Kind);
 
+  /// Get/set what kind of stack protector guard to use.
+  StringRef getStackProtectorGuard() const;
+  void setStackProtectorGuard(StringRef Kind);
+
+  /// Get/set which register to use as the stack protector guard register. The
+  /// empty string is equivalent to "global". Other values may be "tls" or
+  /// "sysreg".
+  StringRef getStackProtectorGuardReg() const;
+  void setStackProtectorGuardReg(StringRef Reg);
+
+  /// Get/set what offset from the stack protector to use.
+  int getStackProtectorGuardOffset() const;
+  void setStackProtectorGuardOffset(int Offset);
+
   /// @name Utility functions for querying and setting the build SDK version
   /// @{
 

include/llvm/Target/TargetOptions.h

@@ -73,8 +73,6 @@ namespace llvm {
     None    // Do not use Basic Block Sections.
   };
 
-  enum class StackProtectorGuards { None, TLS, Global, SysReg };
-
   enum class EABI {
     Unknown,
     Default, // Default means not specified
@@ -328,16 +326,6 @@ namespace llvm {
     /// By default, it is set to false.
     unsigned DebugStrictDwarf : 1;
 
-    /// Stack protector guard offset to use.
-    int StackProtectorGuardOffset = INT_MAX;
-
-    /// Stack protector guard mode to use, e.g. tls, global, sysreg.
-    StackProtectorGuards StackProtectorGuard =
-                                         StackProtectorGuards::None;
-
-    /// Stack protector guard reg to use, e.g. usually fs or gs in X86.
-    std::string StackProtectorGuardReg = "None";
-
     /// Name of the stack usage file (i.e., .su file) if user passes
     /// -fstack-usage. If empty, it can be implied that -fstack-usage is not
     /// passed on the command line.

lib/CodeGen/CommandFlags.cpp

@@ -79,9 +79,6 @@ CGOPT_EXP(bool, FunctionSections)
 CGOPT(bool, IgnoreXCOFFVisibility)
 CGOPT(bool, XCOFFTracebackTable)
 CGOPT(std::string, BBSections)
-CGOPT(std::string, StackProtectorGuard)
-CGOPT(int, StackProtectorGuardOffset)
-CGOPT(std::string, StackProtectorGuardReg)
 CGOPT(unsigned, TLSSize)
 CGOPT(bool, EmulatedTLS)
 CGOPT(bool, UniqueSectionNames)
@@ -366,21 +363,6 @@ codegen::RegisterCodeGenFlags::RegisterCodeGenFlags() {
       cl::init("none"));
   CGBINDOPT(BBSections);
 
-  static cl::opt<std::string> StackProtectorGuard(
-      "stack-protector-guard", cl::desc("Stack protector guard mode"),
-      cl::init("none"));
-  CGBINDOPT(StackProtectorGuard);
-
-  static cl::opt<std::string> StackProtectorGuardReg(
-      "stack-protector-guard-reg", cl::desc("Stack protector guard register"),
-      cl::init("none"));
-  CGBINDOPT(StackProtectorGuardReg);
-
-  static cl::opt<int> StackProtectorGuardOffset(
-      "stack-protector-guard-offset", cl::desc("Stack protector guard offset"),
-      cl::init(INT_MAX));
-  CGBINDOPT(StackProtectorGuardOffset);
-
   static cl::opt<unsigned> TLSSize(
       "tls-size", cl::desc("Bit size of immediate TLS offsets"), cl::init(0));
   CGBINDOPT(TLSSize);
@@ -502,26 +484,6 @@ codegen::getBBSectionsMode(llvm::TargetOptions &Options) {
   }
 }
 
-llvm::StackProtectorGuards
-codegen::getStackProtectorGuardMode(llvm::TargetOptions &Options) {
-  if (getStackProtectorGuard() == "tls")
-    return StackProtectorGuards::TLS;
-  if (getStackProtectorGuard() == "global")
-    return StackProtectorGuards::Global;
-  if (getStackProtectorGuard() == "sysreg")
-    return StackProtectorGuards::SysReg;
-  if (getStackProtectorGuard() != "none") {
-    ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
-        MemoryBuffer::getFile(getStackProtectorGuard());
-    if (!MBOrErr)
-      errs() << "error illegal stack protector guard mode: "
-             << MBOrErr.getError().message() << "\n";
-    else
-      Options.BBSectionsFuncListBuf = std::move(*MBOrErr);
-  }
-  return StackProtectorGuards::None;
-}
-
 // Common utility function tightly tied to the options listed here. Initializes
 // a TargetOptions object with CodeGen flags and returns it.
 TargetOptions
@@ -558,9 +520,6 @@ codegen::InitTargetOptionsFromCodeGenFlags(const Triple &TheTriple) {
   Options.BBSections = getBBSectionsMode(Options);
   Options.UniqueSectionNames = getUniqueSectionNames();
   Options.UniqueBasicBlockSectionNames = getUniqueBasicBlockSectionNames();
-  Options.StackProtectorGuard = getStackProtectorGuardMode(Options);
-  Options.StackProtectorGuardOffset = getStackProtectorGuardOffset();
-  Options.StackProtectorGuardReg = getStackProtectorGuardReg();
   Options.TLSSize = getTLSSize();
   Options.EmulatedTLS = getEmulatedTLS();
   Options.ExplicitEmulatedTLS = EmulatedTLSView->getNumOccurrences() > 0;

lib/CodeGen/StackProtector.cpp

@@ -380,9 +380,8 @@ static Value *getStackGuard(const TargetLoweringBase *TLI, Module *M,
                             IRBuilder<> &B,
                             bool *SupportsSelectionDAGSP = nullptr) {
   Value *Guard = TLI->getIRStackGuard(B);
-  auto GuardMode = TLI->getTargetMachine().Options.StackProtectorGuard;
-  if ((GuardMode == llvm::StackProtectorGuards::TLS ||
-       GuardMode == llvm::StackProtectorGuards::None) && Guard)
+  StringRef GuardMode = M->getStackProtectorGuard();
+  if ((GuardMode == "tls" || GuardMode.empty()) && Guard)
     return B.CreateLoad(B.getInt8PtrTy(), Guard, true, "StackGuard");
 
   // Use SelectionDAG SSP handling, since there isn't an IR guard.

lib/IR/Module.cpp

@@ -686,6 +686,41 @@ void Module::setFramePointer(FramePointerKind Kind) {
   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::Error, "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::Error, "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 INT_MAX;
+}
+
+void Module::setStackProtectorGuardOffset(int Offset) {
+  addModuleFlag(ModFlagBehavior::Error, "stack-protector-guard-offset", Offset);
+}
+
 void Module::setSDKVersion(const VersionTuple &V) {
   SmallVector<unsigned, 3> Entries;
   Entries.push_back(V.getMajor());

lib/Target/AArch64/AArch64InstrInfo.cpp

@@ -1904,10 +1904,10 @@ bool AArch64InstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
   }
 
   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 @@ bool AArch64InstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
     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))

lib/Target/X86/X86ISelLowering.cpp

@@ -2510,15 +2510,16 @@ Value *X86TargetLowering::getIRStackGuard(IRBuilder<> &IRB) const {
       return SegmentOffset(IRB, 0x10, getAddressSpace());
     } else {
       unsigned AddressSpace = getAddressSpace();
+      Module *M = IRB.GetInsertBlock()->getParent()->getParent();
       // Specially, some users may customize the base reg and offset.
-      int Offset = getTargetMachine().Options.StackProtectorGuardOffset;
+      int Offset = M->getStackProtectorGuardOffset();
       // If we don't set -stack-protector-guard-offset value:
       // %fs:0x28, unless we're using a Kernel code model, in which case
       // it's %gs:0x28.  gs:0x14 on i386.
       if (Offset == INT_MAX)
         Offset = (Subtarget.is64Bit()) ? 0x28 : 0x14;
 
-      const auto &GuardReg = getTargetMachine().Options.StackProtectorGuardReg;
+      StringRef GuardReg = M->getStackProtectorGuardReg();
       if (GuardReg == "fs")
         AddressSpace = X86AS::FS;
       else if (GuardReg == "gs")
@@ -2548,12 +2549,11 @@ void X86TargetLowering::insertSSPDeclarations(Module &M) const {
     return;
   }
 
-  auto GuardMode = getTargetMachine().Options.StackProtectorGuard;
+  StringRef GuardMode = M.getStackProtectorGuard();
 
   // glibc, bionic, and Fuchsia have a special slot for the stack guard.
-  if ((GuardMode == llvm::StackProtectorGuards::TLS ||
-       GuardMode == llvm::StackProtectorGuards::None)
-      && hasStackGuardSlotTLS(Subtarget.getTargetTriple()))
+  if ((GuardMode == "tls" || GuardMode.empty()) &&
+      hasStackGuardSlotTLS(Subtarget.getTargetTriple()))
     return;
   TargetLowering::insertSSPDeclarations(M);
 }

test/CodeGen/AArch64/stack-guard-sysreg.ll

@@ -1,46 +1,39 @@
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=0 -verify-machineinstrs -o - | \
+; RUN: split-file %s %t
+; RUN: cat %t/main.ll %t/a.ll > %t/a2.ll
+; RUN: cat %t/main.ll %t/b.ll > %t/b2.ll
+; RUN: cat %t/main.ll %t/c.ll > %t/c2.ll
+; RUN: cat %t/main.ll %t/d.ll > %t/d2.ll
+; RUN: cat %t/main.ll %t/e.ll > %t/e2.ll
+; RUN: cat %t/main.ll %t/f.ll > %t/f2.ll
+; RUN: cat %t/main.ll %t/g.ll > %t/g2.ll
+; RUN: cat %t/main.ll %t/h.ll > %t/h2.ll
+; RUN: cat %t/main.ll %t/i.ll > %t/i2.ll
+; RUN: cat %t/main.ll %t/j.ll > %t/j2.ll
+; RUN: llc %t/a2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NO-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=8 -verify-machineinstrs -o - | \
+; RUN: llc %t/b2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-POSITIVE-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=-8 -verify-machineinstrs -o - | \
+; RUN: llc %t/c2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NEGATIVE-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=1 -verify-machineinstrs -o - | \
+; RUN: llc %t/d2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NPOT-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=-1 -verify-machineinstrs -o - | \
+; RUN: llc %t/e2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-NPOT-NEG-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=257 -verify-machineinstrs -o - | \
+; RUN: llc %t/f2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-257-OFFSET %s
-; RUN: llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=-257 -verify-machineinstrs -o - | \
+; RUN: llc %t/g2.ll -verify-machineinstrs -o - | \
 ; RUN: FileCheck --check-prefix=CHECK --check-prefix=CHECK-MINUS-257-OFFSET %s
 
 ; XFAIL
-; RUN: not --crash llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=32761 -o - 2>&1 | \
+; RUN: not --crash llc %t/h2.ll -o - 2>&1 | \
 ; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
-; RUN: not --crash llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=-4096 -o - 2>&1 | \
+; RUN: not --crash llc %t/i2.ll -o - 2>&1 | \
 ; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
-; RUN: not --crash llc %s --stack-protector-guard=sysreg \
-; RUN:   --stack-protector-guard-reg=sp_el0 \
-; RUN:   --stack-protector-guard-offset=4097 -o - 2>&1 | \
+; RUN: not --crash llc %t/j2.ll -o - 2>&1 | \
 ; RUN: FileCheck --check-prefix=CHECK-BAD-OFFSET %s
 
+;--- main.ll
+
 target triple = "aarch64-unknown-linux-gnu"
 
 ; Verify that we `mrs` from `SP_EL0` twice, rather than load from
@@ -100,6 +93,31 @@ entry:
 
 declare void @baz(i32*)
 
-attributes #0 = { sspstrong }
-
 ; CHECK-BAD-OFFSET: LLVM ERROR: Unable to encode Stack Protector Guard Offset
+
+attributes #0 = { sspstrong }
+!llvm.module.flags = !{!1, !2, !3}
+
+!1 = !{i32 2, !"stack-protector-guard", !"sysreg"}
+!2 = !{i32 2, !"stack-protector-guard-reg", !"sp_el0"}
+
+;--- a.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 0}
+;--- b.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 8}
+;--- c.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 -8}
+;--- d.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 1}
+;--- e.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 -1}
+;--- f.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 257}
+;--- g.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 -257}
+;--- h.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 32761}
+;--- i.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 -4096}
+;--- j.ll
+!3 = !{i32 2, !"stack-protector-guard-offset", i32 4097}

test/CodeGen/X86/stack-protector-3.ll

@@ -1,10 +1,18 @@
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %s | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard=tls -o - < %s | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard=global -o - < %s | FileCheck --check-prefix=CHECK-GLOBAL %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard-reg=fs -o - < %s | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard-reg=gs -o - < %s | FileCheck --check-prefix=CHECK-GS %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard-offset=20 -o - < %s | FileCheck --check-prefix=CHECK-OFFSET %s
-; RUN: llc -mtriple=x86_64-pc-linux-gnu -stack-protector-guard-offset=-20 -o - < %s | FileCheck --check-prefix=CHECK-NEGATIVE-OFFSET %s
+; RUN: split-file %s %t
+; RUN: cat %t/main.ll %t/a.ll > %t/a2.ll
+; RUN: cat %t/main.ll %t/b.ll > %t/b2.ll
+; RUN: cat %t/main.ll %t/c.ll > %t/c2.ll
+; RUN: cat %t/main.ll %t/d.ll > %t/d2.ll
+; RUN: cat %t/main.ll %t/e.ll > %t/e2.ll
+; RUN: cat %t/main.ll %t/f.ll > %t/f2.ll
+; RUN: cat %t/main.ll %t/g.ll > %t/g2.ll
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/a2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/b2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/c2.ll | FileCheck --check-prefix=CHECK-GLOBAL %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/d2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/e2.ll | FileCheck --check-prefix=CHECK-GS %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/f2.ll | FileCheck --check-prefix=CHECK-OFFSET %s
+; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/g2.ll | FileCheck --check-prefix=CHECK-NEGATIVE-OFFSET %s
 
 ; CHECK-TLS-FS-40:       movq    %fs:40, %rax
 ; CHECK-TLS-FS-40:       movq    %fs:40, %rax
@@ -47,6 +55,8 @@
 ; CHECK-GLOBAL-NEXT:  .cfi_def_cfa_offset 32
 ; CHECK-GLOBAL-NEXT:  callq   __stack_chk_fail
 
+;--- main.ll
+
 ; ModuleID = 't.c'
 @.str = private unnamed_addr constant [14 x i8] c"stackoverflow\00", align 1
 @a = dso_local local_unnamed_addr global i8* null, align 8
@@ -75,3 +85,23 @@ declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noa
 attributes #0 = { nounwind sspreq uwtable writeonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" "unsafe-fp-math"="false" "use-soft-float"="false" }
 attributes #1 = { argmemonly nounwind willreturn }
 attributes #2 = { nounwind }
+
+;--- a.ll
+;--- b.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard", !"tls"}
+;--- c.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard", !"global"}
+;--- d.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard-reg", !"fs"}
+;--- e.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard-reg", !"gs"}
+;--- f.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard-offset", i32 20}
+;--- g.ll
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"stack-protector-guard-offset", i32 -20}

test/Linker/stack-protector-guard-module-attrs.ll

@@ -0,0 +1,77 @@
+; RUN: split-file %s %t
+; RUN: not llvm-link %t/a.ll %t/b.ll 2>&1 | FileCheck --check-prefix=CHECK-KIND %s
+; RUN: not llvm-link %t/c.ll %t/d.ll 2>&1 | FileCheck --check-prefix=CHECK-REG %s
+; RUN: not llvm-link %t/e.ll %t/f.ll 2>&1 | FileCheck --check-prefix=CHECK-OFFSET %s
+; RUN: llvm-link %t/g.ll %t/h.ll
+
+; CHECK-KIND: error: linking module flags 'stack-protector-guard': IDs have conflicting values
+; CHECK-REG: error: linking module flags 'stack-protector-guard-reg': IDs have conflicting values
+; CHECK-OFFSET: error: linking module flags 'stack-protector-guard-offset': IDs have conflicting values
+
+;--- a.ll
+; Test that different values of stack-protector-guard fail.
+define void @foo() sspstrong {
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard", !"sysreg"}
+;--- b.ll
+declare void @foo() sspstrong
+define void @bar() sspstrong {
+  call void @foo()
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard", !"global"}
+
+;--- c.ll
+; Test that different values of stack-protector-guard-reg fail.
+define void @foo() sspstrong {
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard-reg", !"sp_el0"}
+;--- d.ll
+declare void @foo() sspstrong
+define void @bar() sspstrong {
+  call void @foo()
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard-reg", !"sp_el1"}
+
+;--- e.ll
+; Test that different values of stack-protector-guard-offset fail.
+define void @foo() sspstrong {
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard-offset", i32 257}
+;--- f.ll
+declare void @foo() sspstrong
+define void @bar() sspstrong {
+  call void @foo()
+  ret void
+}
+!llvm.module.flags = !{!0}
+!0 = !{i32 1, !"stack-protector-guard-offset", i32 256}
+
+;--- g.ll
+; Test that the same values for the three module attributes succeed.
+define void @foo() sspstrong {
+  ret void
+}
+!llvm.module.flags = !{!0, !1, !2}
+!0 = !{i32 1, !"stack-protector-guard", !"sysreg"}
+!1 = !{i32 1, !"stack-protector-guard-reg", !"sp_el0"}
+!2 = !{i32 1, !"stack-protector-guard-offset", i32 257}
+;--- h.ll
+declare void @foo() sspstrong
+define void @bar() sspstrong {
+  call void @foo()
+  ret void
+}
+!llvm.module.flags = !{!0, !1, !2}
+!0 = !{i32 1, !"stack-protector-guard", !"sysreg"}
+!1 = !{i32 1, !"stack-protector-guard-reg", !"sp_el0"}
+!2 = !{i32 1, !"stack-protector-guard-offset", i32 257}