-
Jakob Gruber authored
Semantically, the unwinding info is a variable-size metadata table with untagged (i.e. no relocation needed) contents, packed inside Code objects. This is just like other metadata tables (safepoint table, handler table, constant pool, code comments); but for historical reasons it's been treated differently so far. Unlike these other tables, the unwinding info was located *after* InstructionEnd, and its size was written to the first 8 bytes after InstructionEnd. This CL makes unwinding info handling more consistent with other metadata tables by writing its offset into a dedicated kUnwindingInfoOffsetOffset header slot, and by moving the actual data inside the [InstructionStart,InstructionEnd[ area. In follow-up CLs, this area will be split into dedicated instruction- and metadata areas. A picture is worth 1000 words, before: +--------------------------+ <-- raw_instruction_start() | instructions | | ... | +--------------------------+ | embedded metadata | <-- safepoint_table_offset() | ... | <-- handler_table_offset() | | <-- constant_pool_offset() | | <-- code_comments_offset() | padding to the next | | 8-byte aligned address | +--------------------------+ <-- raw_instruction_end() | [unwinding_info_size] | | as uint64_t | +--------------------------+ <-- unwinding_info_start() | unwinding info | | ... | +--------------------------+ <-- unwinding_info_end() After: +--------------------------+ <-- raw_instruction_start() | instructions | | ... | +--------------------------+ | embedded metadata | <-- safepoint_table_offset() | ... | <-- handler_table_offset() | | <-- constant_pool_offset() | | <-- code_comments_offset() | | <-- unwinding_info_offset() | | +--------------------------+ <-- raw_instruction_end() Bug: v8:11036 Change-Id: I649708821acc5365186ca2c9cff2669fc3e91fd3 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2484795Reviewed-by:
Dominik Inführ <dinfuehr@chromium.org> Reviewed-by:
Leszek Swirski <leszeks@chromium.org> Commit-Queue: Jakob Gruber <jgruber@chromium.org> Cr-Commit-Position: refs/heads/master@{#70640}
c5379162