This CL contains compiler+runtime changes that detect C code
running on Go (not g0, not gsignal) stacks, and it contains
corrections for what it detected.
The detection works by changing the C prologue to use a different
stack guard word in the G than Go prologue does. On the g0 and
gsignal stacks, that stack guard word is set to the usual
stack guard value. But on ordinary Go stacks, that stack
guard word is set to ^0, which will make any stack split
check fail. The C prologue then calls morestackc instead
of morestack, and morestackc aborts the program with
a message about running C code on a Go stack.
This check catches all C code running on the Go stack
except NOSPLIT code. The NOSPLIT code is allowed,
so the check is complete. Since it is a dynamic check,
the code must execute to be caught. But unlike the static
checks we've been using in cmd/ld, the dynamic check
works with function pointers and other indirect calls.
For example it caught sigpanic being pushed onto Go
stacks in the signal handlers.
Fixes#8667.
LGTM=khr, iant
R=golang-codereviews, khr, iant
CC=golang-codereviews, r
https://golang.org/cl/133700043
* byteastring is no longer used
* do not generate ODCL, OAS for globals
(wasn't generating any code but might
save one or two init functions)
* do not call self from Init function
R=ken
OCL=28309
CL=28309
add test for string range.
test has minor failure: after loop the index == len(s); should be len(s)-1
in this case. according to spec, vars are left at position at last
iteration.
R=ken,rsc
DELTA=259 (161 added, 96 deleted, 2 changed)
OCL=27343
CL=27343
in favor of using in-memory copy of symbol table.
$ ls -l pretty pretty.big
-rwxr-xr-x 1 rsc eng 439516 Nov 21 16:43 pretty
-rwxr-xr-x 1 rsc eng 580984 Nov 21 16:20 pretty.big
$
R=r
DELTA=446 (238 added, 178 deleted, 30 changed)
OCL=19851
CL=19884
to string convert. if the byte array has length 0,
the computation of &a[0] throws an index bounds error.
for fixed size arrays, this ends up invoking arrays2d
unnecessarily, but it works.
R=ken
DELTA=304 (44 added, 28 deleted, 232 changed)
OCL=15674
CL=15678
* rewrite lock implementation to be correct
(tip: never assume that an algorithm you found
in a linux man page is correct.)
* delete unneeded void* arg from clone fn
* replace Rendez with Note
* comment mal better
* use 6c -w, fix warnings
* mark all assembly functions 7
R=r
DELTA=828 (338 added, 221 deleted, 269 changed)
OCL=13884
CL=13886
Keith Randall
Russ Cox
Ken Thompson
Rob Pike