Segfault during code generation

[joachimschmidt557]

I don't know if this is related to another issue, but when compiling this code with zig from a2432b6, a segmentation fault occurs:

const std = @import("std");
const fixedBufferStream = std.io.fixedBufferStream;

fn exec(input_stream: var) !void {
    var buf: [1024]u8 = undefined;
    const line = (try input_stream.readUntilDelimiterOrEof(&buf, '\n')) orelse "";
}

pub fn main() !void {
    var in_stream = fixedBufferStream("").inStream();
    try exec(in_stream);
}

Here's the valgrind output:

==8618== Memcheck, a memory error detector
==8618== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==8618== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==8618== Command: zig build-exe asdf.zig
==8618== 
==8618== Invalid read of size 8
==8618==    at 0x541F22C: LLVMBuildInBoundsGEP (in /usr/lib/libLLVM-9.so)
==8618==    by 0xBBC3AC: ir_render_slice(CodeGen*, IrExecutableGen*, IrInstGenSlice*) (codegen.cpp:5455)
==8618==    by 0xBC07E5: ir_render_instruction(CodeGen*, IrExecutableGen*, IrInstGen*) (codegen.cpp:6456)
==8618==    by 0xBC0EE6: ir_render(CodeGen*, ZigFn*) (codegen.cpp:6576)
==8618==    by 0xBC7211: do_code_gen(CodeGen*) (codegen.cpp:7935)
==8618==    by 0xBD2379: codegen_build_and_link(CodeGen*) (codegen.cpp:10689)
==8618==    by 0xBA3130: main0(int, char**) (main.cpp:1256)
==8618==    by 0xBA3A2C: main (main.cpp:1407)
==8618==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==8618== 
Segmentation fault at address 0x0
???:?:?: 0x541f22c in ??? (???)
==8618== Warning: set address range perms: large range [0x59c83000, 0x7048c000) (defined)
==8618== Warning: set address range perms: large range [0x59c83000, 0x7048c000) (undefined)
==8618== Warning: set address range perms: large range [0x7048c000, 0x9209a000) (defined)
==8618== Warning: set address range perms: large range [0x7048c000, 0x9209a000) (undefined)
==8618== Warning: set address range perms: large range [0x9209a000, 0xc4aaf000) (defined)
==8618== Warning: set address range perms: large range [0x9209a000, 0xc4aaf000) (undefined)
???:?:?: 0xbc07e5 in ir_render_instruction (/home/joachim/src/zig/src/codegen.cpp)
???:?:?: 0xbc0ee6 in ir_render (/home/joachim/src/zig/src/codegen.cpp)
???:?:?: 0xbc7211 in do_code_gen (/home/joachim/src/zig/src/codegen.cpp)
???:?:?: 0xbd2379 in codegen_build_and_link (/home/joachim/src/zig/src/codegen.cpp)
???:?:?: 0xba3130 in main0 (/home/joachim/src/zig/src/main.cpp)
???:?:?: 0xba3a2c in main (/home/joachim/src/zig/src/main.cpp)
==8618== 
==8618== Process terminating with default action of signal 6 (SIGABRT)
==8618==    at 0x9A33931: raise (raise.c:51)
==8618==    by 0x9A1D55A: abort (abort.c:79)
==8618==    by 0xCDF098: std.os.abort (os.zig:213)
==8618==    by 0xCFB2AA: std.debug.handleSegfaultLinux (debug.zig:1734)
==8618==    by 0x961411F: ??? (in /usr/lib/libpthread-2.30.so)
==8618==    by 0x541F22B: LLVMBuildInBoundsGEP (in /usr/lib/libLLVM-9.so)
==8618==    by 0xBBC3AC: ir_render_slice(CodeGen*, IrExecutableGen*, IrInstGenSlice*) (codegen.cpp:5455)
==8618==    by 0xBC07E5: ir_render_instruction(CodeGen*, IrExecutableGen*, IrInstGen*) (codegen.cpp:6456)
==8618==    by 0xBC0EE6: ir_render(CodeGen*, ZigFn*) (codegen.cpp:6576)
==8618==    by 0xBC7211: do_code_gen(CodeGen*) (codegen.cpp:7935)
==8618==    by 0xBD2379: codegen_build_and_link(CodeGen*) (codegen.cpp:10689)
==8618==    by 0xBA3130: main0(int, char**) (main.cpp:1256)
==8618== 
==8618== HEAP SUMMARY:
==8618==     in use at exit: 117,146,740 bytes in 900,504 blocks
==8618==   total heap usage: 1,288,643 allocs, 388,139 frees, 167,215,472 bytes allocated
==8618== 
==8618== LEAK SUMMARY:
==8618==    definitely lost: 9,063,466 bytes in 136,116 blocks
==8618==    indirectly lost: 5,000,198 bytes in 76,969 blocks
==8618==      possibly lost: 34,342,479 bytes in 146,765 blocks
==8618==    still reachable: 68,740,597 bytes in 540,654 blocks
==8618==         suppressed: 0 bytes in 0 blocks
==8618== Rerun with --leak-check=full to see details of leaked memory
==8618== 
==8618== For lists of detected and suppressed errors, rerun with: -s
==8618== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)