<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/130269>130269</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            powerpc64-ibm-aix: the `.weak` assembler directive is not supported
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    the `.weak` assembler directive is currently not supported by LLVM (although it is documented https://www.ibm.com/docs/en/ssw_aix_71/assembler/assembler_pdf.pdf). 

In contrast, the `.weak_definition` directive is accepted by the assembly parser, but crashes LLVM later on.

Therefore it is currently impossible to define weak symbols using inline assembly.

---

the `.weak_definition` attribute fails with (https://godbolt.org/z/rderToPx4)

clang version 21.0.0git (https://github.com/llvm/llvm-project.git 5422e2c68107650c33f39e6224d1ff0064467550)
Target: powerpc64-ibm-aix
Thread model: posix
InstalledDir: /opt/compiler-explorer/clang-trunk-20250306/bin
 (in-process)
 "/opt/compiler-explorer/clang-trunk-20250306/bin/clang-21" -cc1 -triple powerpc64-ibm-aix -emit-obj -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name example.c -mrelocation-model pic -pic-level 2 -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -fno-verbose-asm -mconstructor-aliases -fxl-pragma-pack -fno-sized-deallocation -target-cpu pwr7 -mfloat-abi hard -gstrict-dwarf -gno-column-info -debug-info-kind=constructor -dwarf-version=3 -fdebug-compilation-dir=/app -v -fdata-sections -fcoverage-compilation-dir=/app -resource-dir /opt/compiler-explorer/clang-trunk-20250306/lib/clang/21 -internal-isystem /opt/compiler-explorer/clang-trunk-20250306/lib/clang/21/include/ppc_wrappers -internal-isystem /opt/compiler-explorer/clang-trunk-20250306/lib/clang/21/include -internal-isystem /usr/include -ferror-limit 19 -fno-signed-char -fno-use-cxa-atexit -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -fcolor-diagnostics -o /app/output.s -x c <source>
clang -cc1 version 21.0.0git based upon LLVM 21.0.0git default target x86_64-unknown-linux-gnu
#include "..." search starts here:
#include <...> search starts here:
 /opt/compiler-explorer/clang-trunk-20250306/lib/clang/21/include/ppc_wrappers
 /opt/compiler-explorer/clang-trunk-20250306/lib/clang/21/include
 /usr/include
End of search list.
fatal error: error in backend: Not implemented yet.
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: /opt/compiler-explorer/clang-trunk/bin/clang -g -o /app/output.s -fno-verbose-asm -c -target powerpc64 -fcolor-diagnostics -fno-crash-diagnostics -target powerpc64-ibm-aix -v <source>
1.      <eof> parser at end of file
2.      Code generation
 #0 0x0000000003b50668 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3b50668)
 #1 0x0000000003b4e7ac llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3b4e7ac)
 #2 0x0000000003a9e083 llvm::CrashRecoveryContext::HandleExit(int) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3a9e083)
 #3 0x0000000003b4623e llvm::sys::Process::Exit(int, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3b4623e)
 #4 0x0000000000d611db LLVMErrorHandler(void*, char const*, bool) cc1_main.cpp:0:0
 #5 0x0000000003aa8153 llvm::report_fatal_error(llvm::Twine const&, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3aa8153)
 #6 0x0000000003aa82b8 (/opt/compiler-explorer/clang-trunk/bin/clang+0x3aa82b8)
 #7 0x00000000038740e0 llvm::MCXCOFFStreamer::emitXCOFFRefDirective(llvm::MCSymbol const*) (/opt/compiler-explorer/clang-trunk/bin/clang+0x38740e0)
 #8 0x00000000038cb850 bool llvm::function_ref<bool ()>::callback_fn<(anonymous namespace)::AsmParser::parseDirectiveSymbolAttribute(llvm::MCSymbolAttr)::'lambda'()>(long) AsmParser.cpp:0:0
 #9 0x00000000038f0fec llvm::MCAsmParser::parseMany(llvm::function_ref<bool ()>, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+0x38f0fec)
#10 0x00000000038defb0 (anonymous namespace)::AsmParser::parseStatement((anonymous namespace)::ParseStatementInfo&, llvm::MCAsmParserSemaCallback*) AsmParser.cpp:0:0
#11 0x00000000038d1e62 (anonymous namespace)::AsmParser::Run(bool, bool) AsmParser.cpp:0:0
#12 0x0000000004a7ab6c llvm::AsmPrinter::emitInlineAsm(llvm::StringRef, llvm::MCSubtargetInfo const&, llvm::MCTargetOptions const&, llvm::MDNode const*, llvm::InlineAsm::AsmDialect) const (/opt/compiler-explorer/clang-trunk/bin/clang+0x4a7ab6c)
#13 0x0000000004a6fc39 llvm::AsmPrinter::doInitialization(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x4a6fc39)
#14 0x0000000001ef16f9 (anonymous namespace)::PPCAIXAsmPrinter::doInitialization(llvm::Module&) PPCAsmPrinter.cpp:0:0
#15 0x00000000034aec28 llvm::FPPassManager::doInitialization(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x34aec28)
#16 0x00000000034ba02e llvm::legacy::PassManagerImpl::run(llvm::Module&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x34ba02e)
#17 0x0000000003df7c2e 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*) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3df7c2e)
#18 0x00000000044cbac5 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x44cbac5)
#19 0x000000000603bfcc clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-trunk/bin/clang+0x603bfcc)
#20 0x00000000044cc1e5 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-trunk/bin/clang+0x44cc1e5)
#21 0x00000000047a6431 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-trunk/bin/clang+0x47a6431)
#22 0x000000000472706b clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x472706b)
#23 0x0000000004893423 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-trunk/bin/clang+0x4893423)
#24 0x0000000000d63411 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-trunk/bin/clang+0xd63411)
#25 0x0000000000d5bc1d ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#26 0x0000000004518759 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#27 0x0000000003a9df83 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-trunk/bin/clang+0x3a9df83)
#28 0x0000000004518979 clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#29 0x00000000044dc79d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+0x44dc79d)
#30 0x00000000044dd731 clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-trunk/bin/clang+0x44dd731)
#31 0x00000000044e7b6c clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-trunk/bin/clang+0x44e7b6c)
#32 0x0000000000d600d1 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-trunk/bin/clang+0xd600d1)
#33 0x0000000000c21ad4 main (/opt/compiler-explorer/clang-trunk/bin/clang+0xc21ad4)
#34 0x00007e785ce29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#35 0x00007e785ce29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#36 0x0000000000d5b6b5 _start (/opt/compiler-explorer/clang-trunk/bin/clang+0xd5b6b5)
```
clang: error: clang frontend command failed with exit code 70 (use -v to see invocation)
Compiler returned: 70

this came up here https://github.com/rust-lang/rust/pull/137816
cc @daltenty 
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWk1z4zaT_jX0BQUVCVKkdPBBka3dSc284xp733pvKhBoyohBgAuAspxfvwWQEkmN7EzGnlw2lVRk4qOffrrRHwSptWKnAK6j-W_R_OaKtu5Rm-tKyycwjsP-qtT85do9AoryePYM9CnKY0SthbqUYBAXBpgTe0DCItYaA8rJF6S0Q7ZtGm0ccFS-oM-f__0FRWRBpXvU7e4RCedXcM3aGpSf9OhcY6N0FZFNRDbPz88zUdYzpuuIbLhmNiIbUBHZWPu8peKwLZKIbE5Axr-3Da9mDa8ispyhKF5F8eqTQkwrZ6h1EVmjsT5bDpVQwgmtvGoThShj0PQa-DW9iBfUUGO90DUqW4eYofYRbKekpA4M0mrWSX54BAOVNtBrPHAk6kZbK0oJyGkUUADyiJB9qUstLWqtUDsklPQjR9n9vhjj7scbulDnjChbB6iiQlr0LNyjN8KU6p3mpZZups0uIps_I7IxHMyDvjtkEVl2Qpikaof2YKzQCpFkFs_inXAXNhPusS17s0m5P_4PN0b_AczN_Kp5RggQli-SuMjnMUvTKl1CTkjGk6qK4zzL8mI-jzvxD9TswEXpCjX6GUzD8gyLssZUHAK_BihHteYguzk2PP-krKNSAr8Rxj-PyEY3LiIbputGSDAYDo3UJrhOUA8706onTGIyj9M4j8imFCqK_dKFUF4BBtZ2mFBEyM_ueBwkSUQIwowlCDsjGgnfK4gw1MJhXf6BMBeWlhJwZQAQZhKowdQ6XAb3wiVlT6D4MC_QvgcjKgEmPGbUcLynsgWsaA0W4ZoKhSshuwcIDrRuJMwYwrUBqRn1roQDuagRDOFGMCxhDxIRhOvK0Bpwo4VyYKL0hkqJcFVT94jBGKURrqoGdyePuSi90QrhSmlsdKu4UDvs53aP9mBKbQFTWyNcM62sMy1z2mAqBbUebXWQuDF0V1PcUPbUrbPiT-CYA5VHvAi74DKYNS1qnk3hkUpNHaalQI_UcIR31hnBHObP1FQI75TGTMu2VlioSiPMoWx34Td-EopH6c0IEeqW4f48ROlNinDVLemcoeONe9e78aGpaRDe-znUUWx9gNHKK8T0HgzdwRvLDFjdGgb-8U95sRTlcTAiG5IgHMylqMTCvlgH9YdsG5GNUEy2HCKyaRq2fTa0acDYXy7vsoDWmvGUCozRBktRC4eS5dF3dgo4Zo_UdA9aC5gdKKYODsIhXO1Uy0Z2zmZkliBc2SfRYM0NZo_AnrBQeFdXwZ5SG8wF3SltnWAWYY06S3qdW9e0bmYRPiCGonTdWTZKb08hNoSD7-NsSS1w1DZadUlmGOFQ0VY61Lk8OizybZ7hVj0p_aywFKo94J1qfRgn6ZGNiJDZbObDjwVq2COyjhpnkc9VPpRPJ6drPzm9fXXyr_WfXyCg23HiIVG8ulUc6eqopRTW-VxbUUclCt7j80j4gYRCfbz1z_6lnc_mEvpS5gXCyrvPt6v7W2Tb0vscRWW7QwZ8TeQT_t_Lmx6otS34MghRxdHROj79h_ojAPJxFnxZ0hjoExZw1LsZWYeV1FrNBPVATauQZUY0Ae-980GVt3XT-0Ae9__Gq3gWxcs7o3eG1oiaXaja7N9JrNPsh_DulaPxXS5gx3g-pMfLJ82vDFRMH58vHnLr_vwMJl7LKF2Drry_d1Ueog5B5xo-U0bxivhpa80B7UCBCVG786k0RvEhPv6TlvM4zxco2DNdRenKvtjux50RygXCHzqTLYZJhj5vtXUGaB2R3JtNKBeRpS9Efo7tiPwWH3o0pwImTaZYMygou4R1LYGqtvmq7sVOURmRRau6yImk9pu_H1mQPSAjE2R0CfEiHSFbeyN_g5A8X9ZaOTi4buS_qeISbg_ChaLtI1jrpA_Y0jPWcpLCZQt39WL4Y4xojUqt5Yew5mUPyLIxspjnScLLkC5ufczqqDERWey14BFZeSQh84XKpn9whMZYsvXF4Yw1PhrE4b9OzHxqHLpI5mPjdBFuG8LmtgubY-d-ePbNTC8y_0A2OiADG_k5TFIuPkAGKUcnqJjIWBRZDPGIii_r_6y_bjb34Sj7Atk_9AV9ePwNqptjszmh6Mv6PjSAI8O8m50O24B8MUXOysU8DpYYwa9aFQrVrYEqStdhNMBY-mgZpjAqpc8720pF6dr390qrl1q3FoUOowmxbdlNXtn6ruubw58hup4Y6FReHTvWi4T40dNuESkkrUtOI1IMqMjiGJJO0i648HKqfRVXwCZ2uwT1C1UvE1hv8_Nxnt3h63txkibTHLPgUJUx-gnu7x11oWQJ-N5cfjeZ_0lVuj-8F0m7h5que8_o3fc1a3h9kjN9EsjJ39TnW6sisuj4Hnh_S-gkxWS0oGU-dgG_1PRt7fHUfgovYla2nnjBvTNC7b5BdU7HfVt2pYenaxLxxrO6txtfm64jfGXWzb98sTGO08PggOoI_EZQGUrGZbfknf7XkzP4XzqlLq9YunyDOq4_KeEEleLPrlKaHG3NWwlB4_eekx7JgHOSDxOokrxa_pVf3d2tV5_-8_Mq-PWnxRfcbpo8MwqMjOvDzd0dtfYLVXT3T9PXgxnomybQrKQxGRc6EnaUvRzDwwn0p7qRfSHQ_kKsAc2AdZqIeVUwAqibfzq-v3UN29fQaURkMRpe9wjCS0PFoD-Bkxkc_gtUf06_O6GvBYFe5dXZbj2UFesMOj3OzrRW7OEbVGvl7pyJ0vUwvK_6inIjJNyHlx19srGOdyOtEv_bwrY5W-m7iubZCAfbY28xWtS_RthykODgLxb67H97WaW1Vrb1tc6HVC2dIQczT6qWLGMlZfO3QIx6ggdDle1esP2PEmf2X90_HNuID4lEHbIB96TeyOO0rBgb4w5ZanX_MEXl0-ikRv6oiqJHcMJH4jNeWQLzC97f-2vf0QBrHRxdePEhrHm5A6pJXZAVNM_SZIxqY7zNTsdoDOtjAHUiB0DTmqEgRZyX6K0wcpGp1zX4EN_rYA2gp9l6sUwzko5B9_AG7Pv-NfpfhcgPOOA9nAHseQubZkly6kUn2WRlDH35FgrvaRPbR6bzxvbU9L4XcwdqgDyfQp6XLOHoSOo6eQgndlwv1lTKfwNzus-VF_CfZRe_Rx-fRhXiEnEj9peqDDJJ3dk8WRTzZWDg9e4ujL7Z3Y2coRPcO8Y6Weu6poqfn8CLxjplHB1SKZWTXDPk0VOOOS3YbtnhkCTdHyW1gvl8JDymQOFksn-wdYYKZ4_DZ9v190XajMb9lNFrkNWphP6xlvN3XV4wRnH2MotXP_gy61ur7mkF8s2u88xuH_G-ywMc_Htx7kvLYon-P_uCJ3jWUONm8etGX04zKmfFkr_K2nD3dx6SA5WTOHy20E-YdI0_NnV19u7tQ_rETsuT56RnVQXnxTR__wgHv-vSvk7A77r8LKx7pW3-PtKeDN5Q4W3dv4_9Uc56r_gVzHluBuamlU8GRZmz11DejH5PcvmFJP4a4_8gc--vEgMbA1fkrGSIY9572bFoOGINcWH13QuU17Lre8sED2SAOSnDYkYSyjPkAb5TTrfTIOdYQRVQLOYMyJIv415EdyHa3xAPN8NhgM2snuVhx7Bk2HB-viFkMdpu_ZptuAnejrT4YRGQjUTk5yVUXs5Rt_l7rRD26iWNrjOPfjvc63a3klVfkCPWe3BFhQTefTkVPglgmgMqAqWtBYT3yGlkAZAYFc5e3LFgRgZcaxSEm-IiPn60JSxitAbUNuEi_a3rYNNah_trbP87IpumlTIimyQtFknu9WEoymJOpQPlXtAVv075Ml3SK7hOiixJszQmy6vH6zyLs6IoY0LZMivjvJpTmhVQznMyX8TLxZW47m_QiyQmabacpQlZ5vOszIu4AEqqKIuhpkLO_AGaabO7CvfS10kak3x5JWkJ0obPCQlR8IzCaERINL-5MtfhSrtsdzbKYimss8M2TjgJ199_4pWu0A9-fjj56PCqNfL65-_Ye3X21-T_AgAA__8oKeiq">