yonghong-song added a comment.
F7545597: clang-crash.tar <https://reviews.llvm.org/F7545597>
@dblaikie I got a standalone reproducible test now.
-bash-4.4$ pwd
/home/yhs/work/bcc/clang-crash
-bash-4.4$ ls
clang-test.cpp compile.sh README ttest.c ttest.h
-bash-4.4$
README has details how to reproduce the issue. Basically, step 1, build a llvm
with x86/bpf support; step 2, run "compile.sh"; step 3, run the binary
"clang-test" produced in step 2 and you will get IR with missing file content
and segfault.
I did not investigate further, but my above patch does not really fix the
issue. So the right fix should be a different one. There could be multiple
issues with clang remapped files.
It will be great if you or others can help resolve these issues!
2. $ ./compile.sh
3. $ ./clang-test
The test will print IR before JITing for BPF backend.
The IR has something like:
...
!8 = !DIFile(filename: "/virtual/ttest.h", directory: "/tmp", checksumkind:
CSK_MD5, checksum: "6a615c0cc48c46cdbe7d9917c635d292", source: "\0A#define
BPF_PERF_OUTPUT2(_name) \5C\0Astruct _name##_table_t { \5C\0A int key; \5C\0A
unsigned leaf; \5C\0A int (*perf_submit) (void *, void *, unsigned); \5C\0A
int (*perf_submit_skb) (void *, unsigned, void *, unsigned); \5C\0A unsigned
max_entries; \5C\0A}; \5C\0A__attribute__((section(\22maps/perf_output\22)))
\5C\0Astruct _name##_table_t _name = { .max_entries = 0 }\0A\0Aint g;\0A")
!9 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!10 = !DIFile(filename: "/virtual/ttest.c", directory: "/tmp")
!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name:
"probe_table_t", file: !10, line: 3, size: 256, elements: !12)
...
Segmentation fault (core dumped)
Note that the "!10" DIFile does not have source code.
Repository:
rC Clang
https://reviews.llvm.org/D53329
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