diff options
| author | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-07-15 21:17:16 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-07-15 21:17:16 +0000 |
| commit | 4e62f891cdeabc14cf6195a69dc6528aab11e753 (patch) | |
| tree | 3a7e81af0a3e72432c75f043950798b0387de393 /libgo/runtime/proc.c | |
| parent | 2d94f7dea9c73ef3c116a0ddc722724578a860fe (diff) | |
runtime: expose the g variable
Currently, getg is implemented in C, which loads the thread-local
g variable. The g variable is declared static in C.
This CL exposes the g variable, so it can be accessed from the Go
side. This allows the Go compiler to inline getg calls to direct
access of g.
Currently, the actual inlining is only implemented in the gollvm
compiler. The g variable is thread-local and the compiler backend
may choose to cache the TLS address in a register or on stack. If
a thread switch happens the cache may become invalid. I don't
know how to disable the TLS address cache in gccgo, therefore
the inlining of getg is not implemented. In the future gccgo may
gain this if we know how to do it safely.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/186238
From-SVN: r273499
Diffstat (limited to 'libgo/runtime/proc.c')
| -rw-r--r-- | libgo/runtime/proc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c index 26125ccf161..523dfd9ff14 100644 --- a/libgo/runtime/proc.c +++ b/libgo/runtime/proc.c @@ -65,7 +65,7 @@ static void gscanstack(G*); #define __thread #endif -static __thread G *g; +__thread G *g __asm__(GOSYM_PREFIX "runtime.g"); #ifndef SETCONTEXT_CLOBBERS_TLS @@ -320,7 +320,7 @@ runtime_mcall(FuncVal *fv) if(gp != nil) { #ifdef USING_SPLIT_STACK - __splitstack_getcontext((void*)(&g->stackcontext[0])); + __splitstack_getcontext((void*)(&gp->stackcontext[0])); #else // We have to point to an address on the stack that is // below the saved registers. |