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[X86] Support -mstack-protector-guard-symbol
Reviewed By: nickdesaulniers Differential Revision: https://reviews.llvm.org/D129346
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‎clang/docs/ClangCommandLineReference.rst

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@@ -3285,6 +3285,10 @@ Use the given offset for addressing the stack-protector guard
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Use the given reg for addressing the stack-protector guard
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.. option:: -mstack-protector-guard-symbol=<arg>
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Use the given symbol for addressing the stack-protector guard
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.. option:: -mstack-protector-guard=<arg>
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Use the given guard (global, tls) for addressing the stack-protector guard

‎clang/docs/ReleaseNotes.rst

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@@ -548,6 +548,8 @@ X86 Support in Clang
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- Added the ``-m[no-]rdpru`` flag to enable/disable the RDPRU instruction
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provided by AMD Zen2 and later processors. Defined intrinsics for using
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this instruction (see rdpruintrin.h).
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- Support ``-mstack-protector-guard-symbol=[SymbolName]`` to use the given
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symbol for addressing the stack protector guard.
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DWARF Support in Clang
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----------------------

‎clang/include/clang/Basic/CodeGenOptions.h

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@@ -389,6 +389,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
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/// On AArch64 this can only be "sp_el0".
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std::string StackProtectorGuardReg;
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/// Specify a symbol to be the guard value.
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std::string StackProtectorGuardSymbol;
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/// Path to ignorelist file specifying which objects
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/// (files, functions) listed for instrumentation by sanitizer
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/// coverage pass should actually not be instrumented.

‎clang/include/clang/Driver/Options.td

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@@ -3771,6 +3771,9 @@ def mstack_protector_guard_EQ : Joined<["-"], "mstack-protector-guard=">, Group<
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def mstack_protector_guard_offset_EQ : Joined<["-"], "mstack-protector-guard-offset=">, Group<m_Group>, Flags<[CC1Option]>,
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HelpText<"Use the given offset for addressing the stack-protector guard">,
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MarshallingInfoInt<CodeGenOpts<"StackProtectorGuardOffset">, "INT_MAX", "int">;
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def mstack_protector_guard_symbol_EQ : Joined<["-"], "mstack-protector-guard-symbol=">, Group<m_Group>, Flags<[CC1Option]>,
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HelpText<"Use the given symbol for addressing the stack-protector guard">,
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MarshallingInfoString<CodeGenOpts<"StackProtectorGuardSymbol">>;
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def mstack_protector_guard_reg_EQ : Joined<["-"], "mstack-protector-guard-reg=">, Group<m_Group>, Flags<[CC1Option]>,
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HelpText<"Use the given reg for addressing the stack-protector guard">,
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MarshallingInfoString<CodeGenOpts<"StackProtectorGuardReg">>;

‎clang/lib/CodeGen/CodeGenModule.cpp

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@@ -900,6 +900,9 @@ void CodeGenModule::Release() {
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if (!getCodeGenOpts().StackProtectorGuardReg.empty())
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getModule().setStackProtectorGuardReg(
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getCodeGenOpts().StackProtectorGuardReg);
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if (!getCodeGenOpts().StackProtectorGuardSymbol.empty())
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getModule().setStackProtectorGuardSymbol(
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getCodeGenOpts().StackProtectorGuardSymbol);
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if (getCodeGenOpts().StackProtectorGuardOffset != INT_MAX)
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getModule().setStackProtectorGuardOffset(
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getCodeGenOpts().StackProtectorGuardOffset);

‎clang/lib/Driver/ToolChains/Clang.cpp

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@@ -3231,6 +3231,16 @@ static void RenderAnalyzerOptions(const ArgList &Args, ArgStringList &CmdArgs,
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Args.AddAllArgValues(CmdArgs, options::OPT_Xanalyzer);
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}
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static bool isValidSymbolName(StringRef S) {
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if (S.empty())
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return false;
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if (std::isdigit(S[0]))
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return false;
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return llvm::all_of(S, [](char C) { return std::isalnum(C) || C == '_'; });
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}
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static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
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const ArgList &Args, ArgStringList &CmdArgs,
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bool KernelOrKext) {
@@ -3362,6 +3372,16 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
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}
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A->render(Args, CmdArgs);
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}
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if (Arg *A = Args.getLastArg(options::OPT_mstack_protector_guard_symbol_EQ)) {
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StringRef Value = A->getValue();
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if (!isValidSymbolName(Value)) {
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D.Diag(diag::err_drv_argument_only_allowed_with)
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<< A->getOption().getName() << "legal symbol name";
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return;
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}
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A->render(Args, CmdArgs);
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}
33653385
}
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33673387
static void RenderSCPOptions(const ToolChain &TC, const ArgList &Args,

‎clang/test/Driver/stack-protector-guard.c

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@@ -13,6 +13,8 @@
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// RUN: FileCheck -check-prefix=CHECK-FS %s
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// RUN: %clang -### -target x86_64-unknown-unknown -mstack-protector-guard-reg=gs %s 2>&1 | \
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// RUN: FileCheck -check-prefix=CHECK-GS %s
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// RUN: %clang -### -target x86_64-unknown-unknown -mstack-protector-guard-symbol=sym %s 2>&1 | \
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// RUN: FileCheck -check-prefix=CHECK-SYM %s
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1719
// Invalid arch
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// RUN: not %clang -target powerpc64le-linux-gnu -mstack-protector-guard=tls %s 2>&1 | \
@@ -32,10 +34,16 @@
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// RUN: FileCheck -check-prefix=INVALID-REG %s
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// RUN: not %clang -target x86_64-unknown-unknown -c -mstack-protector-guard-reg=ds %s 2>&1 | \
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// RUN: FileCheck -check-prefix=INVALID-REG %s
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// RUN: not %clang -target x86_64-unknown-unknown -c -mstack-protector-guard-symbol=2s %s 2>&1 | \
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// RUN: FileCheck -check-prefix=INVALID-SYM %s
39+
// RUN: not %clang -target x86_64-unknown-unknown -c -mstack-protector-guard-symbol= %s 2>&1 | \
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// RUN: FileCheck -check-prefix=INVALID-SYM %s
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// CHECK-FS: "-cc1" {{.*}}"-mstack-protector-guard-reg=fs"
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// CHECK-GS: "-cc1" {{.*}}"-mstack-protector-guard-reg=gs"
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// INVALID-REG: error: invalid value {{.*}} in 'mstack-protector-guard-reg=', expected one of: fs gs
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// CHECK-SYM: "-cc1" {{.*}}"-mstack-protector-guard-symbol=sym"
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// INVALID-SYM: error: invalid argument 'mstack-protector-guard-symbol=' only allowed with 'legal symbol name'
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// RUN: not %clang -target arm-eabi-c -mstack-protector-guard=tls %s 2>&1 | \
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// RUN: FileCheck -check-prefix=MISSING-OFFSET %s

‎llvm/docs/ReleaseNotes.rst

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@@ -221,6 +221,12 @@ Changes to the DAG infrastructure
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---------------------------------
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Changes to the Metadata Info
225+
---------------------------------
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* Add Module Flags Metadata ``stack-protector-guard-symbol`` which specify a
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symbol for addressing the stack-protector guard.
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Changes to the Debug Info
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---------------------------------
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‎llvm/include/llvm/IR/Module.h

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@@ -911,6 +911,10 @@ class LLVM_EXTERNAL_VISIBILITY Module {
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StringRef getStackProtectorGuardReg() const;
912912
void setStackProtectorGuardReg(StringRef Reg);
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/// Get/set a symbol to use as the stack protector guard.
915+
StringRef getStackProtectorGuardSymbol() const;
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void setStackProtectorGuardSymbol(StringRef Symbol);
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914918
/// Get/set what offset from the stack protector to use.
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int getStackProtectorGuardOffset() const;
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void setStackProtectorGuardOffset(int Offset);

‎llvm/lib/IR/Module.cpp

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@@ -714,6 +714,18 @@ void Module::setStackProtectorGuardReg(StringRef Reg) {
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addModuleFlag(ModFlagBehavior::Error, "stack-protector-guard-reg", ID);
715715
}
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717+
StringRef Module::getStackProtectorGuardSymbol() const {
718+
Metadata *MD = getModuleFlag("stack-protector-guard-symbol");
719+
if (auto *MDS = dyn_cast_or_null<MDString>(MD))
720+
return MDS->getString();
721+
return {};
722+
}
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724+
void Module::setStackProtectorGuardSymbol(StringRef Symbol) {
725+
MDString *ID = MDString::get(getContext(), Symbol);
726+
addModuleFlag(ModFlagBehavior::Error, "stack-protector-guard-symbol", ID);
727+
}
728+
717729
int Module::getStackProtectorGuardOffset() const {
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Metadata *MD = getModuleFlag("stack-protector-guard-offset");
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if (auto *CI = mdconst::dyn_extract_or_null<ConstantInt>(MD))

‎llvm/lib/Target/X86/X86ISelLowering.cpp

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@@ -2845,6 +2845,21 @@ Value *X86TargetLowering::getIRStackGuard(IRBuilderBase &IRB) const {
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AddressSpace = X86AS::FS;
28462846
else if (GuardReg == "gs")
28472847
AddressSpace = X86AS::GS;
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2849+
// Use symbol guard if user specify.
2850+
StringRef GuardSymb = M->getStackProtectorGuardSymbol();
2851+
if (!GuardSymb.empty()) {
2852+
GlobalVariable *GV = M->getGlobalVariable(GuardSymb);
2853+
if (!GV) {
2854+
Type *Ty = Subtarget.is64Bit() ? Type::getInt64Ty(M->getContext())
2855+
: Type::getInt32Ty(M->getContext());
2856+
GV = new GlobalVariable(*M, Ty, false, GlobalValue::ExternalLinkage,
2857+
nullptr, GuardSymb, nullptr,
2858+
GlobalValue::NotThreadLocal, AddressSpace);
2859+
}
2860+
return GV;
2861+
}
2862+
28482863
return SegmentOffset(IRB, Offset, AddressSpace);
28492864
}
28502865
}

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

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@@ -6,15 +6,17 @@
66
; RUN: cat %t/main.ll %t/e.ll > %t/e2.ll
77
; RUN: cat %t/main.ll %t/f.ll > %t/f2.ll
88
; RUN: cat %t/main.ll %t/g.ll > %t/g2.ll
9+
; RUN: cat %t/main.ll %t/h.ll > %t/h2.ll
10+
; RUN: cat %t/existedGV.ll %t/main.ll %t/h.ll > %t/i2.ll
911
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/a2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
1012
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/b2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
1113
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/c2.ll | FileCheck --check-prefix=CHECK-GLOBAL %s
1214
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/d2.ll | FileCheck --check-prefix=CHECK-TLS-FS-40 %s
1315
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/e2.ll | FileCheck --check-prefix=CHECK-GS %s
1416
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/f2.ll | FileCheck --check-prefix=CHECK-OFFSET %s
1517
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/g2.ll | FileCheck --check-prefix=CHECK-NEGATIVE-OFFSET %s
16-
17-
;--- main.ll
18+
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/h2.ll | FileCheck --check-prefix=CHECK-SYM %s
19+
; RUN: llc -mtriple=x86_64-pc-linux-gnu -o - < %t/i2.ll | FileCheck --check-prefix=CHECK-SYMGV %s
1820

1921
; CHECK-TLS-FS-40: movq %fs:40, %rax
2022
; CHECK-TLS-FS-40: movq %fs:40, %rax
@@ -57,7 +59,31 @@
5759
; CHECK-GLOBAL-NEXT: .cfi_def_cfa_offset 32
5860
; CHECK-GLOBAL-NEXT: callq __stack_chk_fail
5961

62+
; CHECK-SYM: movq __woof@GOTPCREL(%rip), %rax
63+
; CHECK-SYM-NEXT: movq %fs:(%rax), %rcx
64+
; CHECK-SYM-NEXT: movq %rcx, 16(%rsp)
65+
; CHECK-SYM: movq %fs:(%rax), %rax
66+
; CHECK-SYM-NEXT: cmpq 16(%rsp), %rax
67+
; CHECK-SYM-NEXT: jne .LBB0_2
68+
; CHECK-SYM: .LBB0_2:
69+
; CHECK-SYM-NEXT: .cfi_def_cfa_offset 32
70+
; CHECK-SYM-NEXT: callq __stack_chk_fai
71+
72+
; CHECK-SYMGV: movq __woof(%rip), %rax
73+
; CHECK-SYMGV-NEXT: movq %rax, 16(%rsp)
74+
; CHECK-SYMGV: cmpq 16(%rsp), %rax
75+
; CHECK-SYMGV-NEXT: jne .LBB0_2
76+
; CHECK-SYMGV: .LBB0_2:
77+
; CHECK-SYMGV-NEXT: .cfi_def_cfa_offset 32
78+
; CHECK-SYMGV-NEXT: callq __stack_chk_fail
79+
6080
; ModuleID = 't.c'
81+
;--- existedGV.ll
82+
83+
@__woof = dso_local local_unnamed_addr global ptr null, align 8
84+
85+
;--- main.ll
86+
6187
@.str = private unnamed_addr constant [14 x i8] c"stackoverflow\00", align 1
6288
@a = dso_local local_unnamed_addr global ptr null, align 8
6389

@@ -104,3 +130,6 @@ attributes #2 = { nounwind }
104130
;--- g.ll
105131
!llvm.module.flags = !{!1}
106132
!1 = !{i32 2, !"stack-protector-guard-offset", i32 -20}
133+
;--- h.ll
134+
!llvm.module.flags = !{!1}
135+
!1 = !{i32 2, !"stack-protector-guard-symbol", !"__woof"}

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