| commit | b7bf9dd9ae20aacf2f82b14c08c7316a588ba90c | [log] [tgz] |
|---|---|---|
| author | Peter Rong <peterrong96@gmail.com> | Tue Sep 16 12:22:42 2025 -0700 |
| committer | GitHub <noreply@github.com> | Tue Sep 16 12:22:42 2025 -0700 |
| tree | dfa0f3403e4f90b5a7bbea28ac97e81c64a2536e | |
| parent | 26549262b3b7ad265d25586be4dca38d37d26069 [diff] |
Reapply "[DebugLine] Correct debug line emittion" (#158343) (#158379) This reverts commit aabf18d7184298566993e3141606cd79ff617d2d. #157529 included a test that used clang, which doesn't exists in some CI. #158343 reverts it. This PR reapplies the original patch with the incorrect test removed. ### Context #99710 introduced `.loc_label` so we can terminate a line sequence. However, it did not advance PC properly. This is problematic for 1-instruction functions as it will have zero-length sequence. The test checked in that PR shows the problem: ``` # CHECK-LINE-TABLE: Address Line Column File ISA Discriminator OpIndex Flags # CHECK-LINE-TABLE-NEXT: ------------------ ------ ------ ------ --- ------------- ------- ------------- # CHECK-LINE-TABLE-NEXT: 0x00000028: 05 DW_LNS_set_column (1) # CHECK-LINE-TABLE-NEXT: 0x0000002a: 00 DW_LNE_set_address (0x0000000000000000) # CHECK-LINE-TABLE-NEXT: 0x00000035: 01 DW_LNS_copy # CHECK-LINE-TABLE-NEXT: 0x0000000000000000 1 1 1 0 0 0 is_stmt # CHECK-LINE-TABLE-NEXT: 0x00000036: 00 DW_LNE_end_sequence # CHECK-LINE-TABLE-NEXT: 0x0000000000000000 1 1 1 0 0 0 is_stmt end_sequence ``` Both rows having PC 0x0 is incorrect, and parsers won't be able to parse them. See more explanation why this is wrong in #154851. ### Design This PR attempts to fix this by advancing the PC to the next available Label, and advance to the end of the section if no Label is available. ### Implementation - `emitDwarfLineEndEntry` will advance PC to the `CurrLabel` - If `CurrLabel` is null, its probably a fake LineEntry we introduced in #110192. In that case look for the next Label - If still not label can be found, use `null` and `emitDwarfLineEndEntry` is smart enough to advance PC to the end of the section - Rename `LastLabel` to `PrevLabel`, "last" can mean "previous" or "final", this is ambigous. - Updated the tests to emit a correct label. ### Note This fix should render #154986 and #154851 obsolete, they were temporary fixes and don't resolve the root cause.
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