275567 2024-06-17 08:07:49 -0700 [Win] Enable BUILTIN_FRAME_ADDRESS using _AddressOfReturnAddress() 2024-06-25 08:17:30 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build PC Windows 10 RESOLVED FIXED InRadar P2 Normal --- 1 ian.grunert webkit-unassigned fujii webkit-bug-importer oldest_to_newest 2041662 0 ian.grunert 2024-06-17 08:07:49 -0700 Disabled on Windows as __builtin_frame_address(1) is unavailable, and cannot be recreated with __builtin_frame_address(0) due to how the stack frame is grown. __builtin_frame_address(0) points at the current frame, and if the current function spills registers to the stack it's pointing at the first of four home spaces. Without knowing the size of the stack frame the compiler reserves we can't walk back up to find the RBP at function entry. Could be implemented on Windows with __builtin_stack_address() once implemented in clang, as that returns the stack pointer at the time of function entry. With that we'd either be able to access the RBP that was pushed to the stack by the function, or we could push it within CCallHelpers so we didn't have to rely on that. Blocked on support for __builtin_stack_address() being added to clang - https://github.com/llvm/llvm-project/issues/82632 2041785 1 ian.grunert 2024-06-17 18:08:16 -0700 __builtin_stack_address() might still not do what we need, it sounds like it might point at the end of the function frame. The overall problem is that on Windows, the frame pointer is after local variables and callee-saved registers. https://learn.microsoft.com/en-us/cpp/build/stack-usage?view=msvc-170 We might be able to get something that works using _AddressOfReturnAddress(). 2042432 2 ian.grunert 2024-06-21 07:46:36 -0700 Pull request: https://github.com/WebKit/WebKit/pull/30043 2042949 3 ews-feeder 2024-06-25 08:17:06 -0700 Committed 280335@main (0ced454cee73): <https://commits.webkit.org/280335@main> Reviewed commits have been landed. Closing PR #30043 and removing active labels. 2042951 4 webkit-bug-importer 2024-06-25 08:17:30 -0700 <rdar://problem/130505408>