<div dir="ltr">Can you post test.obj somewhere, and maybe the LLVM IR if you can get it? If it really was reading address <span style="font-size:12.8px">0xFFFFFFFFFFFFFFFF, then RBP must have been completely corrupted, probably by the prologue.</span></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 30, 2017 at 6:27 PM, Andrew Kelley via llvm-dev <span dir="ltr"><<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I suspect that there are 2 issues here:<div><br></div><div> * I have incorrect alignment somewhere</div><div> * MSVC / .pdb / CodeView debugging is not working correctly.</div><div><br></div><div>I think the latter would help solve the former.</div><div><br></div><div>I will send out a new email later talking about the issues I'm having debugging llvm-generated binaries with MSVC.</div><div><div class="h5"><div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Sep 30, 2017 at 3:33 PM, Andrew Kelley <span dir="ltr"><<a href="mailto:superjoe30@gmail.com" target="_blank">superjoe30@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>I have this code, which works fine on MacOS and Linux hosts:<br></div><div><br></div><div><div> const char *target_specific_cpu_args;</div><div> const char *target_specific_features;</div><div> if (g->is_native_target) {</div><div> target_specific_cpu_args = ZigLLVMGetHostCPUName();</div><div> target_specific_features = ZigLLVMGetNativeFeatures();</div><div> } else {</div><div> target_specific_cpu_args = "";</div><div> target_specific_features = "";</div><div> }</div></div><div><br></div><div><div> g->target_machine = LLVMCreateTargetMachine(target<wbr>_ref, buf_ptr(&g->triple_str),</div><div> target_specific_cpu_args, target_specific_features, opt_level, reloc_mode, LLVMCodeModelDefault);</div></div><div><br></div><div><br></div><div><br></div><div>char *ZigLLVMGetHostCPUName(void) {</div><div> std::string str = sys::getHostCPUName();</div><div> return strdup(str.c_str());</div><div>}</div><div><br></div><div>char *ZigLLVMGetNativeFeatures(void<wbr>) {</div><div> SubtargetFeatures features;</div><div><br></div><div> StringMap<bool> host_features;</div><div> if (sys::getHostCPUFeatures(host_<wbr>features)) {</div><div> for (auto &F : host_features)</div><div> features.AddFeature(F.first(), F.second);</div><div> }</div><div><br></div><div> return strdup(features.getString().c_<wbr>str());</div><div>}</div><div><br></div><div>On this windows laptop that I am testing on, I get these values:</div><div><br></div><div>target_specific_cpu_args: skylake<br></div><div><br></div><div>target_specific_features: +sse2,+cx16,-tbm,-avx512ifma,-<wbr>avx512dq,-fma4,+prfchw,+bmi2,+<wbr>xsavec,+fsgsbase,+popcnt,+aes,<wbr>+xsaves,-avx512er,-avx512vpopc<wbr>ntdq,-clwb,-avx512f,-clzero,-<wbr>pku,+mmx,-lwp,-xop,+rdseed,-<wbr>sse4a,-avx512bw,+clflushopt,+<wbr>xsave,-avx512vl,-avx512cd,+<wbr>avx,-rtm,+fma,+bmi,+rdrnd,-<wbr>mwaitx,+sse4.1,+sse4.2,+avx2,+<wbr>sse,+lzcnt,+pclmul,-<wbr>prefetchwt1,+f16c,+ssse3,+sgx,<wbr>+cmov,-avx512vbmi,+movbe,+<wbr>xsaveopt,-sha,+adx,-avx512pf,+<wbr>sse3<br></div><div><br></div><div><br></div><div>It successfully creates a binary, but the binary when run crashes with:</div><div><br></div><div>Unhandled exception at 0x00007FF7C9913BA7 in test.exe: 0xC0000005: Access violation reading location 0xFFFFFFFFFFFFFFFF.</div><div><br></div><div>The disassembly of the crashed instruction is:</div><div><br></div><div><div>00007FF7C9913BA7 vmovdqa xmmword ptr [rbp-20h],xmm0 </div></div><div><br></div><div>There is no callstack or source in the MSVC debugger. The .pdb produced is 64KB exactly. The file was linked with:</div><div><br></div><div>lld -NOLOGO -DEBUG -MACHINE:X64 /SUBSYSTEM:console -OUT:.\test.exe -NODEFAULTLIB -ENTRY:_start ./zig-cache/test.obj ./zig-cache/builtin.obj ./zig-cache/compiler_rt.obj ./zig-cache/kernel32.lib<br></div><div><br></div><div><br></div><div>When I change the call to LLVMCreateTargetMachine so that both target_specific_cpu_args and target_specific_features are the empty string, the produced binary is valid and runs successfully.</div><div><br></div><div>Is this an LLVM bug? Am I using the API incorrectly? Is there more information I can provide to LLVM-dev mailing list that would make it easier to help me?</div></div>
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