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Merged
merged 1 commit into from
Aug 26, 2018
Merged

Check return value of const_ptr_pointee #1419

merged 1 commit into from
Aug 26, 2018

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kristate
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Thanks to DutchGh0s on IRC.

@andrewrk andrewrk merged commit 0839ed1 into ziglang:master Aug 26, 2018
@andrewrk
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Argh, I think I pulled the trigger too fast. I think that const_ptr_pointee might actually need to assert that its return value is not null, and the problem DutchGh0s ran into was a different thing. Do we have a test case that triggered the issue?

andrewrk added a commit that referenced this pull request Aug 26, 2018
@andrewrk
Revert "src/ir.cpp: check return value of const_ptr_pointee to prot…
6a3fad1 
…ect against dereferencing null pointers;"

This reverts commit 0839ed1.

I realized too late there is a better fix. See PR #1419
@andrewrk
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See 68e2794. If this assert trips, the problem is elsewhere.

@kristate
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@andrewrk I think that it is okay that const_ptr_pointee returns nullptr in some instances -- problem is outside of const_ptr_pointee

@kristate
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btw, here is the backtrace that I am getting on his code on 68e2794:

    frame #0: 0x00007fff5b831b66 libsystem_kernel.dylib`__pthread_kill + 10
  * frame #1: 0x00007fff5b9fc080 libsystem_pthread.dylib`pthread_kill + 333
    frame #2: 0x00007fff5b78d1ae libsystem_c.dylib`abort + 127
    frame #3: 0x00007fff5b7551ac libsystem_c.dylib`__assert_rtn + 320
    frame #4: 0x0000000100054788 zig`const_ptr_pointee(g=0x0000000106806000, const_val=0x000000010ac0f958) at ir.cpp:181
    frame #5: 0x000000010005942f zig`ir_get_deref(ira=0x000000010ac0cf20, source_instruction=0x000000010ac03c10, ptr=0x000000010ac0f940) at ir.cpp:10989
    frame #6: 0x0000000100082218 zig`ir_analyze_instruction_load_ptr(ira=0x000000010ac0cf20, load_ptr_instruction=0x000000010ac03c10) at ir.cpp:14951
    frame #7: 0x0000000100080702 zig`ir_analyze_instruction_nocast(ira=0x000000010ac0cf20, instruction=0x000000010ac03c10) at ir.cpp:20908
    frame #8: 0x0000000100059a0d zig`ir_analyze_instruction(ira=0x000000010ac0cf20, instruction=0x000000010ac03c10) at ir.cpp:21164
    frame #9: 0x0000000100058963 zig`ir_analyze(codegen=0x0000000106806000, old_exec=0x000000010ac03420, new_exec=0x000000010ac0ce30, expected_type=0x000000010540e7a0, expected_type_source_node=0x000000010552a630) at ir.cpp:21219
    frame #10: 0x00000001000585c3 zig`ir_eval_const_value(codegen=0x0000000106806000, scope=0x000000010ac02b70, node=0x000000010552a630, expected_type=0x000000010540e7a0, backward_branch_count=0x00007ffeefbfe448, backward_branch_quota=1000, fn_entry=0x000000010abfb730, c_import_buf=0x0000000000000000, source_node=0x0000000105525dd0, exec_name=0x0000000000000000, parent_exec=0x000000010abfb560) at ir.cpp:9690
    frame #11: 0x00000001000ac1d0 zig`ir_analyze_fn_call(ira=0x000000010abfb650, call_instruction=0x000000010abfa550, fn_entry=0x000000010abfb730, fn_type=0x000000010abfba90, fn_ref=0x000000010abfbbb0, first_arg_ptr=0x0000000000000000, comptime_fn_call=true, fn_inline=FnInlineAuto) at ir.cpp:13183
    frame #12: 0x0000000100085db8 zig`ir_analyze_instruction_call(ira=0x000000010abfb650, call_instruction=0x000000010abfa550) at ir.cpp:13607
    frame #13: 0x000000010008077f zig`ir_analyze_instruction_nocast(ira=0x000000010abfb650, instruction=0x000000010abfa550) at ir.cpp:20918
    frame #14: 0x0000000100059a0d zig`ir_analyze_instruction(ira=0x000000010abfb650, instruction=0x000000010abfa550) at ir.cpp:21164
    frame #15: 0x0000000100058963 zig`ir_analyze(codegen=0x0000000106806000, old_exec=0x000000010abf9640, new_exec=0x000000010abfb560, expected_type=0x0000000105407eb0, expected_type_source_node=0x0000000105525b90) at ir.cpp:21219
    frame #16: 0x00000001000585c3 zig`ir_eval_const_value(codegen=0x0000000106806000, scope=0x000000010abf8d90, node=0x0000000105525b90, expected_type=0x0000000105407eb0, backward_branch_count=0x00007ffeefbfe448, backward_branch_quota=1000, fn_entry=0x000000010abf6aa0, c_import_buf=0x0000000000000000, source_node=0x0000000105524ed0, exec_name=0x0000000000000000, parent_exec=0x000000010abf68d0) at ir.cpp:9690
    frame #17: 0x00000001000ac1d0 zig`ir_analyze_fn_call(ira=0x000000010abf69c0, call_instruction=0x000000010abf6680, fn_entry=0x000000010abf6aa0, fn_type=0x000000010abf7660, fn_ref=0x000000010abf7780, first_arg_ptr=0x0000000000000000, comptime_fn_call=true, fn_inline=FnInlineAuto) at ir.cpp:13183
    frame #18: 0x0000000100085db8 zig`ir_analyze_instruction_call(ira=0x000000010abf69c0, call_instruction=0x000000010abf6680) at ir.cpp:13607
    frame #19: 0x000000010008077f zig`ir_analyze_instruction_nocast(ira=0x000000010abf69c0, instruction=0x000000010abf6680) at ir.cpp:20918
    frame #20: 0x0000000100059a0d zig`ir_analyze_instruction(ira=0x000000010abf69c0, instruction=0x000000010abf6680) at ir.cpp:21164
    frame #21: 0x0000000100058963 zig`ir_analyze(codegen=0x0000000106806000, old_exec=0x000000010abf6120, new_exec=0x000000010abf68d0, expected_type=0x0000000105407eb0, expected_type_source_node=0x0000000105524ed0) at ir.cpp:21219
    frame #22: 0x00000001000585c3 zig`ir_eval_const_value(codegen=0x0000000106806000, scope=0x000000010abf5710, node=0x0000000105524ed0, expected_type=0x0000000105407eb0, backward_branch_count=0x00007ffeefbfe448, backward_branch_quota=1000, fn_entry=0x0000000000000000, c_import_buf=0x0000000000000000, source_node=0x0000000105524ed0, exec_name=0x0000000000000000, parent_exec=0x0000000000000000) at ir.cpp:9690
    frame #23: 0x000000010000a735 zig`analyze_const_value(g=0x0000000106806000, scope=0x000000010abf5710, node=0x0000000105524ed0, type_entry=0x0000000105407eb0, type_name=0x0000000000000000) at analyze.cpp:1264
    frame #24: 0x000000010000a625 zig`analyze_type_expr(g=0x0000000106806000, scope=0x000000010abf5710, node=0x0000000105524ed0) at analyze.cpp:1270
    frame #25: 0x000000010001cebd zig`analyze_fn_type(g=0x0000000106806000, proto_node=0x0000000105524c50, child_scope=0x000000010abf5710, fn_entry=0x000000010abf53a0) at analyze.cpp:1641
    frame #26: 0x000000010000d391 zig`resolve_decl_fn(g=0x0000000106806000, tld_fn=0x000000010abf43e0) at analyze.cpp:3180
    frame #27: 0x000000010000b4f3 zig`resolve_top_level_decl(g=0x0000000106806000, tld=0x000000010abf43e0, pointer_only=false, source_node=0x000000010552d9b0) at analyze.cpp:3673
    frame #28: 0x00000001000aa768 zig`ir_analyze_decl_ref(ira=0x000000010abe59f0, source_instruction=0x000000010abe3140, tld=0x000000010abf43e0) at ir.cpp:14504
    frame #29: 0x00000001000842d0 zig`ir_analyze_instruction_field_ptr(ira=0x000000010abe59f0, field_ptr_instruction=0x000000010abe3140) at ir.cpp:14684
    frame #30: 0x0000000100080766 zig`ir_analyze_instruction_nocast(ira=0x000000010abe59f0, instruction=0x000000010abe3140) at ir.cpp:20916
    frame #31: 0x0000000100059a0d zig`ir_analyze_instruction(ira=0x000000010abe59f0, instruction=0x000000010abe3140) at ir.cpp:21164
    frame #32: 0x0000000100058963 zig`ir_analyze(codegen=0x0000000106806000, old_exec=0x000000010abdee00, new_exec=0x000000010abdeee8, expected_type=0x000000010540e7a0, expected_type_source_node=0x000000010552cff0) at ir.cpp:21219
    frame #33: 0x0000000100011570 zig`analyze_fn_ir(g=0x0000000106806000, fn_table_entry=0x000000010abded90, return_type_node=0x000000010552cff0) at analyze.cpp:4048
    frame #34: 0x00000001000114c1 zig`analyze_fn_body(g=0x0000000106806000, fn_table_entry=0x000000010abded90) at analyze.cpp:4136
    frame #35: 0x00000001000126a3 zig`semantic_analyze(g=0x0000000106806000) at analyze.cpp:4341
    frame #36: 0x0000000100032cd4 zig`gen_root_source(g=0x0000000106806000) at codegen.cpp:7162
    frame #37: 0x0000000100032788 zig`codegen_build(g=0x0000000106806000) at codegen.cpp:7669
    frame #38: 0x00000001000c65d7 zig`main(argc=3, argv=0x00007ffeefbff910) at main.cpp:907
    frame #39: 0x00007fff5b6e1015 libdyld.dylib`start + 1

@kristate
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@andrewrk

17:37 <andrewrk> kristate, 68e279 should trip the assert for the bug. do we have a test case? 
17:38 <kristate> andrewrk: the test case was/is a somewhat long file from DutchGh0s 
17:38 <kristate> I will post it in its entirety

This is the file that trips assert: dutchgh0s_issue1419.txt

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@kristate @andrewrk