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Merged
merged 1 commit into from
Mar 5, 2021

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Fix the line directives at the beginning of emit.mlp files in the backend directory to refer to their new source location (instead of the original asmcomp directory). It fixes error locations reported by the compiler when these files are modified.

@mshinwell mshinwell merged commit b0c5105 into oxcaml:4.11 Mar 5, 2021
poechsel pushed a commit to poechsel/flambda-backend that referenced this pull request May 26, 2021
antalsz added a commit to antalsz/flambda-backend that referenced this pull request May 31, 2023
antalsz added a commit to antalsz/flambda-backend that referenced this pull request May 31, 2023
antalsz added a commit to antalsz/flambda-backend that referenced this pull request Jun 5, 2023
antalsz added a commit that referenced this pull request Jun 5, 2023
* Parse `#0`, `-#1`, `#2.7`, and `-#3.1`, treating them as boxed

* Fix parsing of unsuffixed unboxed int literals

* Rewrite CR comment

* Update comment

* promote-menhir

* Unboxed literal tests

* Adjust error for unsuffixed unboxed integers
NickBarnes pushed a commit to NickBarnes/oxcaml that referenced this pull request Feb 3, 2025
The toplevel printer detects cycles by keeping a hashtable of values
that it has already traversed.

However, some OCaml runtime types (at least bigarrays) may be
partially uninitialized, and hashing them at arbitrary program points
may read uninitialized memory. In particular, the OCaml testsuite
fails when running with a memory-sanitizer enabled, as bigarray
printing results in reads to uninitialized memory:

```
==133712==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0x4e6d11 in caml_ba_hash /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45
    oxcaml#1 0x52474a in caml_hash /var/home/edwin/git/ocaml/runtime/hash.c:251:35
    oxcaml#2 0x599ebf in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1065:14
    oxcaml#3 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
    oxcaml#4 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
    oxcaml#5 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
    oxcaml#6 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
    oxcaml#7 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)

  Uninitialized value was created by a heap allocation
    #0 0x47d306 in malloc (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x47d306) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
    oxcaml#1 0x4e7960 in caml_ba_alloc /var/home/edwin/git/ocaml/runtime/bigarray.c:246:12
    oxcaml#2 0x4e801f in caml_ba_create /var/home/edwin/git/ocaml/runtime/bigarray.c:673:10
    oxcaml#3 0x59b8fc in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1058:14
    oxcaml#4 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
    oxcaml#5 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
    oxcaml#6 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
    oxcaml#7 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
    oxcaml#8 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)

SUMMARY: MemorySanitizer: use-of-uninitialized-value /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 in caml_ba_hash
```

The only use of hashing in genprintval is to avoid cycles, that is, it
is only useful for OCaml values that contain other OCaml values
(including possibly themselves). Bigarrays cannot introduce cycles,
and they are always printed as "<abstr>" anyway.

The present commit proposes to be more conservative in which values
are hashed by the cycle detector to avoid this issue: we skip hashing
any value with tag above No_scan_tag -- which may not contain any
OCaml values.

Suggested-by: Gabriel Scherer <[email protected]>

Signed-off-by: Edwin Török <[email protected]>
Co-authored-by: Edwin Török <[email protected]>
NickBarnes pushed a commit to NickBarnes/oxcaml that referenced this pull request Feb 3, 2025
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