bjoernager/rust
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Alex Brachet 5d88d36053 Don't internalize __llvm_profile_counter_bias 
Currently, LLVM profiling runtime counter relocation cannot be
used by rust during LTO because symbols are being internalized
before all symbol information is known.

This mode makes LLVM emit a __llvm_profile_counter_bias symbol
which is referenced by the profiling initialization, which itself
is pulled in by the rust driver here [1].

It is enabled with -Cllvm-args=-runtime-counter-relocation for
platforms which are opt-in to this mode like Linux. On these
platforms there will be no link error, rather just surprising
behavior for a user which request runtime counter relocation.
The profiling runtime will not see that symbol go on as if it
were never there. On Fuchsia, the profiling runtime must have
this symbol which will cause a hard link error.

As an aside, I don't have enough context as to why rust's LTO
model is how it is. AFAICT, the internalize pass is only safe
to run at link time when all symbol information is actually
known, this being an example as to why. I think special casing
this symbol as a known one that LLVM can emit which should not
have it's visbility de-escalated should be fine given how
seldom this pattern of defining an undefined symbol to get
initilization code pulled in is. From a quick grep,
__llvm_profile_runtime is the only symbol that rustc does this
for.

[1] 0265a3e93b/compiler/rustc_codegen_ssa/src/back/linker.rs (L598)
2022-12-07 16:32:59 +00:00
..
rustc
rustc_abi Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514 2022-12-03 17:37:42 +01:00
rustc_apfloat
rustc_arena rustc_arena: remove a couple of ref patterns 2022-11-22 18:49:29 +00:00
rustc_ast Rollup merge of #105142 - nbdd0121:inline_const, r=petrochenkov 2022-12-04 11:38:51 +01:00
rustc_ast_lowering Rollup merge of #104199 - SarthakSingh31:issue-97417-1, r=cjgillot 2022-12-03 17:37:41 +01:00
rustc_ast_passes Auto merge of #104861 - nnethercote:attr-cleanups, r=petrochenkov 2022-12-01 07:13:45 +00:00
rustc_ast_pretty Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514 2022-12-03 17:37:42 +01:00
rustc_attr Rename NestedMetaItem::[Ll]iteral as NestedMetaItem::[Ll]it. 2022-11-28 15:18:53 +11:00
rustc_baked_icu_data Update crate documentation of rustc_baked_icu_data crate 2022-11-18 14:46:36 -08:00
rustc_borrowck Create format_args as late as possible 2022-12-01 08:49:51 +00:00
rustc_builtin_macros Rollup merge of #104614 - Nilstrieb:type-ascribe!, r=TaKO8Ki 2022-12-02 08:28:08 +01:00
rustc_codegen_cranelift Auto merge of #97485 - bjorn3:new_archive_writer, r=wesleywiser 2022-12-03 15:07:39 +00:00
rustc_codegen_gcc Auto merge of #97485 - bjorn3:new_archive_writer, r=wesleywiser 2022-12-03 15:07:39 +00:00
rustc_codegen_llvm Don't internalize __llvm_profile_counter_bias 2022-12-07 16:32:59 +00:00
rustc_codegen_ssa Auto merge of #97485 - bjorn3:new_archive_writer, r=wesleywiser 2022-12-03 15:07:39 +00:00
rustc_const_eval Rollup merge of #105136 - RalfJung:deref-promotion-comment, r=oli-obk 2022-12-02 08:28:10 +01:00
rustc_data_structures Auto merge of #105218 - matthiaskrgr:rollup-8d3k08n, r=matthiaskrgr 2022-12-03 21:25:45 +00:00
rustc_driver Remove -Zno-interleave-lints. 2022-12-02 13:59:28 +11:00
rustc_error_codes Auto merge of #103491 - cjgillot:self-rpit, r=oli-obk 2022-11-21 12:17:03 +00:00
rustc_error_messages Rewrite LLVM's archive writer in Rust 2022-11-26 19:35:32 +00:00
rustc_errors Remove useless borrows and derefs 2022-12-01 17:34:43 +00:00
rustc_expand Rollup merge of #104199 - SarthakSingh31:issue-97417-1, r=cjgillot 2022-12-03 17:37:41 +01:00
rustc_feature Stabilize native library modifier verbatim 2022-11-27 22:36:32 +03:00
rustc_fs_util Remove useless borrows and derefs 2022-12-01 17:34:43 +00:00
rustc_graphviz Remove useless borrows and derefs 2022-12-01 17:34:43 +00:00
rustc_hir Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514 2022-12-03 17:37:42 +01:00
rustc_hir_analysis Auto merge of #103293 - est31:untwist_and_drop_order, r=nagisa 2022-12-04 14:03:12 +00:00
rustc_hir_pretty Rollup merge of #104199 - SarthakSingh31:issue-97417-1, r=cjgillot 2022-12-03 17:37:41 +01:00
rustc_hir_typeck Rollup merge of #104856 - luqmana:associated-const-bad-suggestion, r=compiler-errors 2022-12-04 11:38:50 +01:00
rustc_incremental Prefer doc comments over //-comments in compiler 2022-11-27 11:19:04 +00:00
rustc_index move things from rustc_target::abi to rustc_abi 2022-11-24 16:26:13 +03:30
rustc_infer Rollup merge of #105188 - compiler-errors:verbose-ty-err, r=TaKO8Ki 2022-12-03 12:51:30 +09:00
rustc_interface Remove -Zno-interleave-lints. 2022-12-02 13:59:28 +11:00
rustc_lexer Auto merge of #104507 - WaffleLapkin:asderefsyou, r=wesleywiser 2022-11-24 00:17:35 +00:00
rustc_lint Auto merge of #104863 - nnethercote:reduce-lint-macros, r=cjgillot 2022-12-02 15:31:15 +00:00
rustc_lint_defs Make deref_into_dyn_supertrait lint the impl and not the usage 2022-11-23 15:40:27 +00:00
rustc_llvm Use LLVM for getting symbols from COFF bigobj files 2022-11-26 19:35:32 +00:00
rustc_log
rustc_macros Remove useless borrows and derefs 2022-12-01 17:34:43 +00:00
rustc_metadata Make inferred_outlives_crate return Clause 2022-11-29 12:01:58 -03:00
rustc_middle Auto merge of #105121 - oli-obk:simpler-cheaper-dump_mir, r=nnethercote 2022-12-04 05:47:10 +00:00
rustc_mir_build Auto merge of #105121 - oli-obk:simpler-cheaper-dump_mir, r=nnethercote 2022-12-04 05:47:10 +00:00
rustc_mir_dataflow Create format_args as late as possible 2022-12-01 08:49:51 +00:00
rustc_mir_transform Auto merge of #105121 - oli-obk:simpler-cheaper-dump_mir, r=nnethercote 2022-12-04 05:47:10 +00:00
rustc_monomorphize Prefer doc comments over //-comments in compiler 2022-11-27 11:19:04 +00:00
rustc_parse Rollup merge of #104199 - SarthakSingh31:issue-97417-1, r=cjgillot 2022-12-03 17:37:41 +01:00
rustc_parse_format shift no characters when using raw string literals 2022-11-15 14:28:20 +09:00
rustc_passes rustc_hir: Change representation of import paths to support multiple resolutions 2022-12-01 18:51:05 +03:00
rustc_plugin_impl
rustc_privacy Auto merge of #99798 - JulianKnodt:ac1, r=BoxyUwU 2022-11-25 22:56:59 +00:00
rustc_query_impl Auto merge of #104940 - cjgillot:query-feed-simple, r=oli-obk 2022-11-30 17:20:14 +00:00
rustc_query_system Fill in def_span when creating def ids. 2022-12-01 10:33:28 +00:00
rustc_resolve fix #105069, Add AmbiguityError for inconsistent resolution for an import 2022-12-03 22:28:35 +08:00
rustc_save_analysis rustc_hir: Change representation of import paths to support multiple resolutions 2022-12-01 18:51:05 +03:00
rustc_serialize rename {max=>largest}_max_leb128_len 2022-11-29 17:58:09 +00:00
rustc_session Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514 2022-12-03 17:37:42 +01:00
rustc_smir
rustc_span Rollup merge of #105050 - WaffleLapkin:uselessrefign, r=jyn514 2022-12-03 17:37:42 +01:00
rustc_symbol_mangling Rollup merge of #104786 - WaffleLapkin:amp-mut-help, r=compiler-errors 2022-11-26 17:47:23 +01:00
rustc_target Rollup merge of #105123 - BlackHoleFox:fixing-the-macos-deployment, r=oli-obk 2022-12-04 11:38:51 +01:00
rustc_trait_selection Rollup merge of #104199 - SarthakSingh31:issue-97417-1, r=cjgillot 2022-12-03 17:37:41 +01:00
rustc_traits Make ObligationCtxt::normalize take cause by borrow 2022-11-28 17:35:40 +00:00
rustc_transmute Auto merge of #103831 - chenyukang:yukang/fix-103751-ice, r=nagisa 2022-11-05 13:48:30 +00:00
rustc_ty_utils Auto merge of #105012 - WaffleLapkin:into, r=oli-obk 2022-11-29 13:28:44 +00:00
rustc_type_ir Remove some unnecessary slicing 2022-11-21 20:38:55 +00:00