Variables in data sections of 32-bit executables interfere with
garbage collector's ability to free objects and/or unnecessarily
slow down the garbage collector.
This changeset moves some static variables to .noptr sections.
'files' in symtab.c is now allocated dynamically.
R=golang-dev, dvyukov, minux.ma
CC=golang-dev
https://golang.org/cl/9786044
The linker can generate split stack prolog when a textflag 7 function
makes an indirect function call. If it happens, badsignal() crashes
trying to dereference g.
Fixes#5337.
R=bradfitz, dave, adg, iant, r, minux.ma
CC=adonovan, golang-dev
https://golang.org/cl/9226043
thread_GOOS.c becomes os_GOOS.c.
signal_GOOS_GOARCH.c becomes os_GOOS_GOARCH.c,
but with non-GOARCH-specific code moved into os_GOOS.c.
The actual arch-specific signal handler moves into signal_GOARCH.c
to avoid per-GOOS duplication.
New files signal_GOOS_GOARCH.h provide macros for
accessing fields of the very system-specific signal info structs.
Lots moving, but nothing changing.
This is a preliminarly cleanup so I can work on the signal
handling code to fix some open issues without having to
make each change 13 times.
Tested on Linux and OS X, 386 and amd64.
Will fix Plan 9, Windows, and ARM after the fact if necessary.
(Plan 9 and Windows should be fine; ARM will probably have some typos.)
Net effect: -1081 lines of code.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/7565048
