<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/148579>148579</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [Clang] Clang crashed when compiling with `-mllvm -print-changed=dot-cfg`
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          cabbaken
      </td>
    </tr>
</table>

<pre>
    Code:
```c
void do_something();
int main() {
  for(int i = 0; i < 10; ++i)
 do_something();
}
```
compile with
```bash
clang -mllvm -print-changed=dot-cfg t.c 
```
will crash. Below is the crash info:
```plaintext
clang -mllvm -print-changed=dot-cfg ttt.c 
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /home/ruoyu/llvm_install/bin/clang-21 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -dumpdir a- -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name ttt.c -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fdebug-compilation-dir=/home/ruoyu/work/test -fcoverage-compilation-dir=/home/ruoyu/work/test -resource-dir /home/ruoyu/llvm_install/lib/clang/21 -internal-isystem /home/ruoyu/llvm_install/lib/clang/21/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/11/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -ferror-limit 19 -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -mllvm -print-changed=dot-cfg -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/ttt-c61253.o -x c ttt.c
1.      <eof> parser at end of file
2.      Optimizer
3.      Running pass "function(ee-instrument<>)" on module "ttt.c"
 #0 0x000055f51f538270 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/ruoyu/llvm_install/bin/clang-21+0x3d0d270)
 #1 0x000055f51f535b4c SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x00007f3b1eb28520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #3 0x000055f5205fd9f0 (anonymous namespace)::DotCfgDiff::createDisplayGraph(llvm::StringRef, llvm::StringRef) StandardInstrumentations.cpp:0:0
 #4 0x000055f520617b45 llvm::DotCfgChangeReporter::handleFunctionCompare(llvm::StringRef, llvm::StringRef, llvm::StringRef, llvm::StringRef, bool, unsigned int, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&) (/home/ruoyu/llvm_install/bin/clang-21+0x4decb45)
 #5 0x000055f520619669 std::_Function_handler<void (bool, unsigned int, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&), llvm::DotCfgChangeReporter::handleInitialIR(llvm::Any)::'lambda'(bool, unsigned int, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&)>::_M_invoke(std::_Any_data const&, bool&&, unsigned int&&, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&) StandardInstrumentations.cpp:0:0
 #6 0x000055f5205efc37 void llvm::function_ref<void (llvm::FuncDataT<llvm::DCData> const*, llvm::FuncDataT<llvm::DCData> const*)>::callback_fn<llvm::IRComparer<llvm::DCData>::compare(bool, std::function<void (bool, unsigned int, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&)>)::'lambda'(llvm::FuncDataT<llvm::DCData> const*, llvm::FuncDataT<llvm::DCData> const*)>(long, llvm::FuncDataT<llvm::DCData> const*, llvm::FuncDataT<llvm::DCData> const*) (/home/ruoyu/llvm_install/bin/clang-21+0x4dc4c37)
 #7 0x000055f52061058f llvm::OrderedChangedData<llvm::FuncDataT<llvm::DCData>>::report(llvm::OrderedChangedData<llvm::FuncDataT<llvm::DCData>> const&, llvm::OrderedChangedData<llvm::FuncDataT<llvm::DCData>> const&, llvm::function_ref<void (llvm::FuncDataT<llvm::DCData> const*, llvm::FuncDataT<llvm::DCData> const*)>) (/home/ruoyu/llvm_install/bin/clang-21+0x4de558f)
 #8 0x000055f520610aa7 llvm::IRComparer<llvm::DCData>::compare(bool, std::function<void (bool, unsigned int, llvm::FuncDataT<llvm::DCData> const&, llvm::FuncDataT<llvm::DCData> const&)>) (/home/ruoyu/llvm_install/bin/clang-21+0x4de5aa7)
 #9 0x000055f520610fe2 llvm::DotCfgChangeReporter::handleInitialIR(llvm::Any) (/home/ruoyu/llvm_install/bin/clang-21+0x4de5fe2)
#10 0x000055f52061297b llvm::ChangeReporter<llvm::IRDataT<llvm::DCData>>::saveIRBeforePass(llvm::Any, llvm::StringRef, llvm::StringRef) (/home/ruoyu/llvm_install/bin/clang-21+0x4de797b)
#11 0x000055f520612b6b void llvm::detail::UniqueFunctionBase<void, llvm::StringRef, llvm::Any>::CallImpl<llvm::ChangeReporter<llvm::IRDataT<llvm::DCData>>::registerRequiredCallbacks(llvm::PassInstrumentationCallbacks&)::'lambda'(llvm::StringRef, llvm::Any)>(void*, llvm::StringRef, llvm::Any&) (/home/ruoyu/llvm_install/bin/clang-21+0x4de7b6b)
#12 0x000055f51eee875a llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/home/ruoyu/llvm_install/bin/clang-21+0x36bd75a)
#13 0x000055f51f7da39e (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#14 0x000055f51f7de50d clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/home/ruoyu/llvm_install/bin/clang-21+0x3fb350d)
#15 0x000055f51fe55e73 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/home/ruoyu/llvm_install/bin/clang-21+0x462ae73)
#16 0x000055f52172cf7c clang::ParseAST(clang::Sema&, bool, bool) (/home/ruoyu/llvm_install/bin/clang-21+0x5f01f7c)
#17 0x000055f520187cde clang::FrontendAction::Execute() (/home/ruoyu/llvm_install/bin/clang-21+0x495ccde)
#18 0x000055f5200f6dcb clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/ruoyu/llvm_install/bin/clang-21+0x48cbdcb)
#19 0x000055f520262a88 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/ruoyu/llvm_install/bin/clang-21+0x4a37a88)
#20 0x000055f51c69bb7c cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/ruoyu/llvm_install/bin/clang-21+0xe70b7c)
#21 0x000055f51c692db2 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#22 0x000055f51c696bef clang_main(int, char**, llvm::ToolContext const&) (/home/ruoyu/llvm_install/bin/clang-21+0xe6bbef)
#23 0x000055f51c52105b main (/home/ruoyu/llvm_install/bin/clang-21+0xcf605b)
#24 0x00007f3b1eb0fd90 __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#25 0x00007f3b1eb0fe40 call_init ./csu/../csu/libc-start.c:128:20
#26 0x00007f3b1eb0fe40 __libc_start_main ./csu/../csu/libc-start.c:379:5
#27 0x000055f51c692815 _start (/home/ruoyu/llvm_install/bin/clang-21+0xe67815)
clang: error: unable to execute command: Segmentation fault
clang: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 21.0.0git
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/ruoyu/llvm_install/bin
clang: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /tmp/ttt-8e6328.c
clang: note: diagnostic msg: /tmp/ttt-8e6328.sh
clang: note: diagnostic msg: 

********************
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWllz46q2_jXkhcIlI8uyH_Kg2HF3qva-nUqyz3l0IViSOY1AB1CG--tvgeRYdtKd6Q676nalEwnBWh_fGhiZc7LWAOcou0DZ-ox1fmfsOWdlyX6CPiuNeDpfGQEoLVBSoHnS_3CUFPdGCizM1pkG_E7qGtEFokuUXqCkkNrjhkndl2GUh0KMK2MRXYSPEqN0jROUXsTHFZ7GZ0QvEL2QQU5S_FI6ytdjNCgpuGlaqQA_SL8bfyqZC-9cMV1j0ih132DSWqk94TumaxAoXQvjCa9q7Cccn8h9kEphbpnbTfAFKPOApcN-B30ZlroyJ9S0iknt4dG_X60fFF__cVncXmLXlY30mOGyq7GF1liPvcE771sXlNENopta-l1XTrhpEN0E-cMf0lrzL-Ae0Y10rgOH6AYzLbDUXHUCRuBLxn96yzggusKthdYaDs6BwM50ti8OLZlzhkvmQWDbaey4la2foKS49Yz_xKJr2p6DZILjv2trassazGzdNaB9QI0R3exMA4hubGeeugHuVmrnmVKIbsrgLZtIGaFTTDifYuKtbBXgx8V8O5-RTv_U5kETJXX3SGrdYQKN9MSU_8Ik4BDSYkYwEdKxUgGpLAAmXAGzhDlPSqiMBRJ6Dloc6kXm7sHKSoKNxZxZQe6Z6oBo1oDDJLgzqaTqCwarkcaCMpx5aTRpjACFW8kxaSUnCu5BYdq_SEdaCZg0lWUNkNYEJ7EoXTOlMKka5ncErNUGk6pqCTc6mMajdG00JpU2xJpOC6lrEupi0nCjnbcd98YSpiRzAWTV6QepBfGhWw6la4qJZ7YGT3jbBR7JfIaJ7zTEgho02ABYQNnVNdjwKURbuq5FiUkVy0kfXn0vhQywX5rzwdifiG48OI9Jxc09WFbDx5ta6N0v1H7ba5Qs916D6Cb4TSRWM0Wke3Iemo_LCLEzRMur0jpnQyvDmXpn1aig5hzRzeDKzy6M6GYaNE4mL3-9UvelNngMD_yl1qHqK3J-3_rjKjCpwFpjiZIhc02XmFS17ngIKSeNRul6NqGTKSaV-ylbYoQlfAf8J5Ga1E0V_UUZS4RktTbOS-7eTJukYkJYJ2tM1tvtt9Vq-734x-V2_c_iZkO3q83Vtrj9E6XrKSYmIPZNG357T_h8SrN0YjB5xLwPZJQU0yF7oXQFpkLpJW6ZdWAx8zgkC1PhEP0oKehQ80frZSP_EyxKinQou-l0iB_cMucworTqNA--j-gCgMgYsiEnonSF0sswolGKjcaNEZ2C0KLHQ2kYABFNE5w8JkmSZFmVTassXdA8wTHhpwVKC_fk-ofrQFPMyHd9Tl8cKln2sDXOW2ANovOQ16X2cVwOg-qH8jKiF8ljKhJB82QYpRFNpycgs3LG8a2sNVPfmRYKhmE_qHayDsPm1iNahPcwj4iPy6GFm_A2jChJ_N8roIOCvErLKZR0kdFkQN8H1yuhomTJJ85M5hHzjGZ0hDgdIaZJVollFQUybfRTYzqHY9pvI5XLnsa18auqXsuq6t-5BeZhLV2r2NM3y9rdEeu33kpd30AVevlq8RLfeqYFs-Lq2TFipnyNgtkR4vk0L2fZSGwPbhXD5CZOGsLwEr7sogU2gyOuTNMyCx9E-tHi0hgV_nY6TjAFHox_qB7wrJlndyhdjXqxCmUh-OLwNnjrZ1p92rlnAng5yw6ukp0Qv5zPl9h50eve7ond7gZPT1dxaozo4m_AwnHDt5zkSksvmbq6OXKPQj89xwCiuWJNKRii-d-kh-nlYIk_t1Lfm5_Btw_mKfTTVjDPjhT1sOfD2zH4-RfAfNZVP5AG5seJCyqe5jGHjlTvB52thWrkjh_GVnyqR8XYKJwpFabb20oftbq6GRKRfV3Y0Po5We0d7dmwzwPr3yvc-jH9tVD5X2afLpQJ89nPifik4s_nXD7jaX7IuflJzk2yRTWC9MMKsCD6RCZ6IKt3I352r35xfWSbL0v-hQ_9T8n9e4T6l0bbLFtUB8svTi3PWI7_n-SNr5DI2Ch8lqckVkD_m6YBX8FYAe0xhiVDcoKRLvNyhPEU3dHY8Z7gduwerm4u4o7PNXPuZV8-Nqn9Ss_zZV4eej497Xk5L0-HcAGeSdU__6Xlv7vnCfwFczA477u6ELq652TFlLpqWnVE3ZeZtlBL58HewL87GZLcMOYfUx5scDK_GVWcvz1s_qZ_-yHveS35Tl6-ulDIy_nIrnS8CgaARZ4xfEzAn0yz-oTkP-PS_xQcU09O_q7-2ACdPmJqL3H-GaFf4iSdlyLP2IGT9GhnIBcsXcJb6-zLRvrCOWhK9fQdVLtPTjedHrZcovdcyxaU1CHL93t3sdJFv7dbDLsuo8zfxTDatv6455Y9bNsHKz1s91sko0YCKtYpvxWgwMMbDXuT9LS_pfbOGPWj823nN7K3_nt0nrQaK3zJwcpo1zVgh7nZUPqXl-pkXREMNTsxFGSJGMuERvpBQg_gmPZVfwBjQ4QzzeElqJUR8A2iBY12L5zzF1G6d-Xi9S4ezDxKWtrbzsl7uIFqpf31CfH31bBjFhi8jRuakcT_C095h9U-G4hVmWaJOARidmRfyDLI099pj4X95t2dZdr1W_h_aXli-OL2bmX6A6-vZdM5ZZCnB8BHC91pTnmV8zHga2YdFLd3x3BuoWFHi_z9308Dy6pkWuX8AOx4bTJd5FzAGNjGBj6efbNPaY_AOw_749BPUrTMOBdwQHI8V06queAl_l1QjrHsQ2fxa-hfM-iCl4KPhsfjSSmdU7ZYjNEOuA6g74eDtbcyzZdWnizN2WLxjJIe7bfz-bIsg9vx6XY4zh4Np9ayp5u47OI7Zg9roiGyj8qON7o_CRbypBx5Ip2eYKWipHhP42p6Fx1_PINqmFL_AO6NHWaBL4GfpOUgY4jvox0rYeU92JfjCKUnmOYlVL2V9wwOq6ugOtJRvE_jZzmblyVUB86OJiQ8o9MkK-NVhc8q4NU8yQ5uTmfHRxVJJZYJ3m6VLPnWeWb9ljOlIhl4EoS5bn_e556cgNYhutGtH04mXzSa7FBaZAuUFtP5oDI7VQmzBMcGUkt_qqV_DKJJFD3hQRYNEuneivPXJB514jX8r0pO8zCtywbB-anLLqYZ7kV-3sL5Yjrs1-_zBI7nkeGh06xUgL3B0AcG5qZpmA6jNr6F-nkxguPw_aqM_h5HNSTHvQBcMalAYNFF8S4eXoVOdA4wuY9lAFiO8tgzRDycjGI6nSSTpJZB8V08qA8Kf3XfIVTaWWACx7sGoWprnHxESXHVUwRiLe2771uMOqtNmLQU-HAEixsXv0TLfeEnKQ53W4q7u2L1Hd99v8SbH3_88eOfV__xDW-u_ri8xXc_YvHFX9_wzeX1j5s7FC-VXL92MWXhQkb45eWU5woWcLydAQIz38t7T4fHh8ULmKd0EU-IP9n0cAPpbZ6_TvX-HtKZOE_FMl2yMzif5hmd5Ys8zc925_N8lguokrxKlovptJrlaZmyWSXyZcnSNDmT5zShWZJPZ0meLrJ8wiDhdMbLqspyPocczRJomFST4FETY-uzeNXofDpbZPnyTLESlItXyigdblVQlK3P7HloQMqudmiWKOm8O4jw0qt4D20VW2RrHB_6u0og8MMONO4vk0hdx4teGM2TN24JBCI6q84_f3lq6NT9Of2vAAAA___ewx3C">