1846795 - Add a mechanism to detect (in)correctly placed slow callsites

Status: NEW

(Core :: JavaScript: WebAssembly, enhancement, P3)

Description

[Yury Delendik (:yury)]

Wasm tail calls logic relies on call-sites to be marked as "slow" if it has a logic to restore heap registers and realm. It will be nice to verify in DEBUG, that these markers are properly placed.

Currently selected markers:

Platform	Instruction	Binary encoding
x64	OR r14, 0	49 83 CE 00
x86	OR esi, esi	0B F6
Aarch64	MOV x28, x28	AA1C03FC
ARM	AND lr, lr, lr	E00EE00E

Comment 1

[Yury Delendik (:yury)]

From https://phabricator.services.mozilla.com/D190942:

the same issue here that we had with trap offset marking [...may arise]? Where MacroAssembler::call on some platforms could insert extra instructions that cause the no-op we insert here to be in the wrong location?