In signal-triggered stack scan, if the signal is delivered at
certain bad time (e.g. in vdso, or in the middle of setcontext?),
the unwinder may not be able to unwind the whole stack, while it
still reports _URC_END_OF_STACK. So we cannot rely on _URC_END_OF_STACK
to tell if it successfully scanned the stack. Instead, we check
the last Go frame to see it actually reached the end of the stack.
For Go-created stack, this is runtime.kickoff. For C-created
stack, we need to record the outermost Go frame when it enters
the Go side.
Also we cannot unwind the stack if the signal is delivered in the
middle of runtime.gogo, halfway through a goroutine switch, where
the g and the stack don't match. Give up in this case as well.
Reviewed-on: https://go-review.googlesource.com/c/159098
From-SVN: r269018
Precise stack scan needs to unwind the stack. When it is
unwinding the stack, if a profiling signal arrives, which also
does a traceback, it may deadlock in dl_iterate_phdr. Prevent
this deadlock by setting up runtime_in_callers before traceback.
Reviewed-on: https://go-review.googlesource.com/c/155766
From-SVN: r267457
On ARM32 EABI, unlike other platforms, the personality function is
called during _Unwind_Backtrace (libgcc/unwind-arm-common.inc:581).
In this case, simply unwind the frame without returning any
handlers. Otherwise traceback will loop if there is a frame with
a defer on stack.
Reviewed-on: https://go-review.googlesource.com/c/155759
From-SVN: r267434
On ARM32 EABI, when the "compact" unwinding model is used, it
does not have standard LSDA and _Unwind_GetLanguageSpecificData
will not return data that is parseable by us. Check this
conditon before calling _Unwind_GetLanguageSpecificData.
Fix ARM32 build.
Reviewed-on: https://go-review.googlesource.com/c/155758
From-SVN: r267428
The type table encoding can be DW_EH_PE_absptr, but this case
was missing, which was causing abort on ARM32 EABI. Add the
missing case.
Reviewed-on: https://go-review.googlesource.com/c/153857
From-SVN: r267070
ARM32 EABI unwinder does not define _URC_NORMAL_STOP. Instead,
it has _URC_FAILURE. Use _URC_FAILURE there.
Should fix ARM32 build.
Reviewed-on: https://go-review.googlesource.com/c/153417
From-SVN: r267033
This CL adds support of precise stack scan using stack maps to
the runtime. The stack maps are generated by the compiler (if
supported). Each safepoint is associated with a (real or dummy)
landing pad, and its "type info" in the exception table is a
pointer to the stack map. When a stack is scanned, the stack map
is found by the stack unwinding code by inspecting the exception
table (LSDA).
For precise stack scan we need to unwind the stack. There are
three cases:
- If a goroutine is scanning its own stack, it can unwind the
stack and scan the frames.
- If a goroutine is scanning another, stopped, goroutine, it
cannot directly unwind the target stack. We handle this by
switching (runtime.gogo) to the target g, letting it unwind
and scan the stack, and switch back.
- If we are scanning a goroutine that is blocked in a syscall,
we send a signal to the target goroutine's thread, and let the
signal handler unwind and scan the stack. Extra care is needed
as this races with enter/exit syscall.
Currently this is only implemented on linux.
Reviewed-on: https://go-review.googlesource.com/c/140518
From-SVN: r266832
The C portion of the Go runtime includes the header "unwind-pe.h" from
libgcc, which contains some constants and a few small routines for
decoding pointer values within unwind info. This patch gets rid of
that include and instead adds a re-implementation of that
functionality in the single file that uses it. The intent is to allow
the C runtime portion of libgo to be built without a companion GCC
installation.
Reviewed-on: https://go-review.googlesource.com/90235
From-SVN: r259861
The actual stack unwind code is still in C, but the rest of the code,
notably all the memory allocation, is now in Go. The names are changed
to the names used in the Go 1.7 runtime, but the code is necessarily
somewhat different.
The __go_makefunc_can_recover function is dropped, as the uses of it
were removed in https://golang.org/cl/198770044.
Reviewed-on: https://go-review.googlesource.com/33414
From-SVN: r242715
I started to copy the Go 1.7 interface code, but the gc and gccgo
representations of interfaces are too different. So instead I rewrote
the gccgo interface code from C to Go. The code is largely the same as
it was, but the names are more like those used in the gc runtime.
I also copied over the string comparison functions, and tweaked the
compiler to use eqstring when comparing strings for equality.
Reviewed-on: https://go-review.googlesource.com/31591
From-SVN: r241384
Use the new -fgo-c-header option to build a header file for the Go
runtime code in libgo/go/runtime, and use the new header file in the C
runtime code in libgo/runtime. This will ensure that the Go code and C
code share the same data structures as we convert the runtime from C to
Go.
The new file libgo/go/runtime/runtime2.go is copied from the Go 1.7
release, and then edited to remove unnecessary data structures and
modify others for use with libgo.
The new file libgo/go/runtime/mcache.go is an initial version of the
same files in the Go 1.7 release, and will be replaced by the Go 1.7
file when we convert to the new memory allocator.
The new file libgo/go/runtime/type.go describes the gccgo version of the
reflection data structures, and replaces the Go 1.7 runtime file which
describes the gc version of those structures.
Using the new header file means changing a number of struct fields to
use Go naming conventions (that is, no underscores) and to rename
constants to have a leading underscore so that they are not exported
from the Go package. These names were updated in the C code.
The C code was also changed to drop the thread-local variable m, as was
done some time ago in the gc sources. Now the m field is always
accessed using g->m, where g is the single remaining thread-local
variable. This in turn required some adjustments to set g->m correctly
in all cases.
Also pass the new -fgo-compiling-runtime option when compiling the
runtime package, although that option doesn't do anything yet.
Reviewed-on: https://go-review.googlesource.com/28051
From-SVN: r239872
gcc/:
* gcc.c (default_compilers): Add entry for ".go".
* common.opt: Add -static-libgo as a driver option.
* doc/install.texi (Configuration): Mention libgo as an option for
--enable-shared. Mention go as an option for --enable-languages.
* doc/invoke.texi (Overall Options): Mention .go as a file name
suffix. Mention go as a -x option.
* doc/frontends.texi (G++ and GCC): Mention Go as a supported
language.
* doc/sourcebuild.texi (Top Level): Mention libgo.
* doc/standards.texi (Standards): Add section on Go language.
Move references for other languages into their own section.
* doc/contrib.texi (Contributors): Mention that I contributed the
Go frontend.
gcc/testsuite/:
* lib/go.exp: New file.
* lib/go-dg.exp: New file.
* lib/go-torture.exp: New file.
* lib/target-supports.exp (check_compile): Match // Go.
From-SVN: r167407
