someone972, I tried compiling Kvre manually (instead of using CMake) and it produces different code, which works:
pushq %rbp movq %rsp, %rbp subq $0xa0, %rsp movq %rdi, -0x50(%rbp) movq %rsi, -0x58(%rbp) movq -0x50(%rbp), %rsi movq %rsi, %rdi addq $0x90, %rdi movq %rdi, -0x38(%rbp) movq -0x38(%rbp), %rdi movq (%rdi), %rax cmpq 0x8(%rdi), %rax movq %rsi, -0x80(%rbp) jne 0x801cbcce3 ; <+275> at model.cpp:86 movq -0x80(%rbp), %rdi callq 0x801cbb484 ; symbol stub for: kvre::Model::get_num_vertices() const movq %rax, -0x60(%rbp) movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x80(%rbp), %rdi movq %rax, -0x88(%rbp) callq 0x801cbb484 ; symbol stub for: kvre::Model::get_num_vertices() const movq -0x88(%rbp), %rdi movq %rax, %rsi resize(unsigned long) movq $0x0, -0x68(%rbp) movq -0x68(%rbp), %rax cmpq -0x60(%rbp), %rax jae 0x801cbccde ; <+270> at model.cpp:86 movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x68(%rbp), %rcx movq %rax, -0x8(%rbp) movq %rcx, -0x10(%rbp) movq -0x8(%rbp), %rax movq (%rax), %rax shlq $0x4, %rcx addq %rcx, %rax movq -0x80(%rbp), %rcx movq 0x30(%rcx), %rdx movq 0x48(%rcx), %rsi movq (%rdx), %rdi movq 0x30(%rdi), %rdi movq -0x68(%rbp), %r8 movq %rdi, -0x90(%rbp) movq %rdx, %rdi movq %r8, %rdx movq -0x90(%rbp), %r8 movq %rax, -0x98(%rbp) callq *%r8 movlps %xmm0, -0x78(%rbp) movlps %xmm1, -0x70(%rbp) movq -0x78(%rbp), %rax movq -0x98(%rbp), %rcx movq %rax, (%rcx) movq -0x70(%rbp), %rax movq %rax, 0x8(%rcx) movq -0x68(%rbp), %rax addq $0x1, %rax movq %rax, -0x68(%rbp) jmp 0x801cbcc48 ; <+120> at model.cpp:81 jmp 0x801cbcce3 ; <+275> at model.cpp:86 movl $0xffffffff, %eax ; imm = 0xFFFFFFFF movl %eax, %ecx cmpq %rcx, -0x58(%rbp) jne 0x801cbcd55 ; <+389> at model.cpp:97 leaq 0xeb26(%rip), %rdi ; + 545 movq -0x80(%rbp), %rax addq $0x90, %rax movq %rax, -0x18(%rbp) movq $0x0, -0x20(%rbp) movq -0x18(%rbp), %rax movq -0x20(%rbp), %rcx shlq $0x4, %rcx addq (%rax), %rcx movq (%rcx), %rax movq %rax, -0x48(%rbp) movq 0x8(%rcx), %rax movq %rax, -0x40(%rbp) cvtss2sd -0x48(%rbp), %xmm0 cvtss2sd -0x44(%rbp), %xmm1 cvtss2sd -0x40(%rbp), %xmm2 cvtss2sd -0x3c(%rbp), %xmm3 movb $0x4, %al callq 0x801cbb004 ; symbol stub for: printf movl %eax, -0x9c(%rbp) jmp 0x801cbcd89 ; <+441> at model.cpp:98 movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x58(%rbp), %rcx movq %rax, -0x28(%rbp) movq %rcx, -0x30(%rbp) movq -0x28(%rbp), %rax movq -0x30(%rbp), %rcx shlq $0x4, %rcx addq (%rax), %rcx movq (%rcx), %rax movq %rax, -0x48(%rbp) movq 0x8(%rcx), %rax movq %rax, -0x40(%rbp) movq -0x48(%rbp), %xmm0 ; xmm0 = mem[0],zero movq -0x40(%rbp), %xmm1 ; xmm1 = mem[0],zero addq $0xa0, %rsp popq %rbp retq
(The old, formatted the same, for reference):
pushq %rbp movq %rsp, %rbp subq $0xb0, %rsp movq %rdi, -0x50(%rbp) movq %rsi, -0x58(%rbp) movq -0x50(%rbp), %rsi movq %rsi, %rdi addq $0x90, %rdi movq %rdi, -0x38(%rbp) movq -0x38(%rbp), %rdi movq (%rdi), %rax cmpq 0x8(%rdi), %rax movq %rsi, -0x80(%rbp) jne 0x801cbc885 ; <+293> at model.cpp:86 movq -0x80(%rbp), %rdi callq 0x801cbb3cc ; symbol stub for: kvre::Model::get_num_vertices() const movq %rax, -0x60(%rbp) movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x80(%rbp), %rdi movq %rax, -0x88(%rbp) callq 0x801cbb3cc ; symbol stub for: kvre::Model::get_num_vertices() const movq -0x88(%rbp), %rdi movq %rax, %rsi resize(unsigned long) movq $0x0, -0x68(%rbp) movq -0x68(%rbp), %rax cmpq -0x60(%rbp), %rax jae 0x801cbc880 ; <+288> at model.cpp:86 movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x68(%rbp), %rcx movq %rax, -0x8(%rbp) movq %rcx, -0x10(%rbp) movq -0x8(%rbp), %rax movq -0x10(%rbp), %rcx shlq $0x4, %rcx addq (%rax), %rcx movq -0x80(%rbp), %rax movq 0x30(%rax), %rdx movq (%rdx), %rsi movq 0x30(%rsi), %rsi movq 0x48(%rax), %rdi movq -0x68(%rbp), %r8 movq %rdi, -0x90(%rbp) movq %rdx, %rdi movq -0x90(%rbp), %rdx movq %rsi, -0x98(%rbp) movq %rdx, %rsi movq %r8, %rdx movq -0x98(%rbp), %r8 movq %rcx, -0xa0(%rbp) callq *%r8 movq %rax, -0x78(%rbp) movq %rdx, -0x70(%rbp) movq -0x78(%rbp), %rax movq -0xa0(%rbp), %rcx movq %rax, (%rcx) movq -0x70(%rbp), %rax movq %rax, 0x8(%rcx) movq -0x68(%rbp), %rax addq $0x1, %rax movq %rax, -0x68(%rbp) jmp 0x801cbc7d8 ; <+120> at model.cpp:81 jmp 0x801cbc885 ; <+293> at model.cpp:86 movl $0xffffffff, %eax ; imm = 0xFFFFFFFF movl %eax, %ecx cmpq %rcx, -0x58(%rbp) jne 0x801cbc8f7 ; <+407> at model.cpp:97 leaq 0xedc0(%rip), %rdi ; + 413 movq -0x80(%rbp), %rax addq $0x90, %rax movq %rax, -0x18(%rbp) movq $0x0, -0x20(%rbp) movq -0x18(%rbp), %rax movq -0x20(%rbp), %rcx shlq $0x4, %rcx addq (%rax), %rcx movq (%rcx), %rax movq %rax, -0x48(%rbp) movq 0x8(%rcx), %rax movq %rax, -0x40(%rbp) cvtss2sd -0x48(%rbp), %xmm0 cvtss2sd -0x44(%rbp), %xmm1 cvtss2sd -0x40(%rbp), %xmm2 cvtss2sd -0x3c(%rbp), %xmm3 movb $0x4, %al callq 0x801cbaf5c ; symbol stub for: printf movl %eax, -0xa4(%rbp) jmp 0x801cbc92b ; <+459> at model.cpp:98 movq -0x80(%rbp), %rax addq $0x90, %rax movq -0x58(%rbp), %rcx movq %rax, -0x28(%rbp) movq %rcx, -0x30(%rbp) movq -0x28(%rbp), %rax movq -0x30(%rbp), %rcx shlq $0x4, %rcx addq (%rax), %rcx movq (%rcx), %rax movq %rax, -0x48(%rbp) movq 0x8(%rcx), %rax movq %rax, -0x40(%rbp) movq -0x48(%rbp), %rax movq -0x40(%rbp), %rdx addq $0xb0, %rsp popq %rbp retq
I ran a diff and it appears to be handling return values differently, but I wouldn't even say I have a crude understanding of x86 assembly, so I'm not certain.
I'm not sure why CMake is making Clang generate bad code, but I'm going to switch to a different build system regardless. I want to generate reproducible builds, for defensive reasons, so I'm going to test Bazle first. If that fails, back to Premake...
At least I can make a working build, though:
{"name":"610904","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/4\/84d6aa90839758934758e79e747c5eb3.png","w":1290,"h":749,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/4\/84d6aa90839758934758e79e747c5eb3"}
(I'm trying to make a utility that allows users to customize an online game's [RuneScape] drawing behavior. For example, making certain obnoxious MTX creatures render at 50% translucency or changing the GUI colors.)
Have you tried using Clang's static analyzer? (a simple command line switch)
Using LLVM 5.0's static analyzer across my entire suite of libraries under the KOMPROMAT module, there were a whopping half-a-dozen minor errors, none of them related to my problem. I'm surprised there were so few--I either ran the tool wrong or I'm the best. 
Valgrind does not guarantee there is no corruption. Have you tried the hundreds of additional flags/checks that can be turned on with Valgrind?
To be honest, no, but after I narrowed it down to a code generation problem, I stopped pursuing possible memory corruption. I make extensive use of modern C++ semantics like shared pointers, as well as using C++ containers whenever possible, so the scope of memory corruption is limited to a few specific places (marshaling graphics data, mostly).
edit: I switched to Bazel and the code is generated correctly now. Cookies.
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