From c19759aa487f7d6f479daa00e7462425f4efc481 Mon Sep 17 00:00:00 2001 From: Austin Clements Date: Tue, 13 Apr 2021 08:44:56 -0400 Subject: runtime: eliminate externalthreadhandler This function is no longer used. Eliminating this actually fixes several problems: - It made assumptions about what registers memclrNoHeapPointers would preserve. Besides being an abstraction violation and lurking maintenance issue, this actively became a problem for regabi because the call to memclrNoHeapPointers now happens through an ABI wrapper, which is generated by the compiler and hence we can't easily control what registers it clobbers. - The amd64 implementation (at least), does not interact with the host ABI correctly. Notably, it doesn't save many of the registers that are callee-save in the host ABI but caller-save in the Go ABI. - It interacts strangely with the NOSPLIT checker because it allocates an entire M and G on its stack. It worked around this on arm64, and happened to do things the NOSPLIT checker couldn't track on 386 and amd64, and happened to be *4 bytes* below the limit on arm (so any addition to the m or g structs would cause a NOSPLIT failure). See CL 309031 for a more complete explanation. Fixes #45530. Updates #40724. Change-Id: Ic70d4d7e1c17f1d796575b3377b8529449e93576 Reviewed-on: https://go-review.googlesource.com/c/go/+/309634 Trust: Austin Clements Run-TryBot: Austin Clements TryBot-Result: Go Bot Reviewed-by: Michael Pratt Reviewed-by: Michael Knyszek --- src/runtime/symtab.go | 1 - 1 file changed, 1 deletion(-) (limited to 'src/runtime/symtab.go') diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go index a382cf6002..c0630c874e 100644 --- a/src/runtime/symtab.go +++ b/src/runtime/symtab.go @@ -317,7 +317,6 @@ const ( funcID_asyncPreempt funcID_cgocallback funcID_debugCallV1 - funcID_externalthreadhandler funcID_gcBgMarkWorker funcID_goexit funcID_gogo -- cgit v1.3