fba70f605e
Currently, the compiler lowers runtime.getcallersp to
__builtin_frame_address(1). In the C side of the runtime,
getcallersp is defined as __builtin_frame_address(0). They don't
match. Further, neither of them actually returns the caller's SP.
On AMD64, __builtin_frame_address(0) just returns the frame
pointer. __builtin_frame_address(1) returns the memory content
where the frame pointer points to, which is typically the
caller's frame pointer but can also be garbage if the frame
pointer is not enabled.
This CL changes it to use __builtin_dwarf_cfa(), which returns
the caller's SP at the call site. This matches the SP we get
from unwinding the stack.
Currently getcallersp is not used for anything real. It will be
used for precise stack scan (a new version of CL 159098).
Reviewed-on: https://go-review.googlesource.com/c/162905
* go-gcc.cc (Gcc_backend::Gcc_backend): Define __builtin_dwarf_cfa
instead of __builtin_frame_address.
From-SVN: r268952
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| .. | ||
| config | ||
| go | ||
| misc/cgo | ||
| runtime | ||
| testsuite | ||
| LICENSE | ||
| MERGE | ||
| Makefile.am | ||
| Makefile.in | ||
| PATENTS | ||
| README | ||
| README.gcc | ||
| VERSION | ||
| aclocal.m4 | ||
| check-packages.txt | ||
| config.h.in | ||
| configure | ||
| configure.ac | ||
| goarch.sh | ||
| godeps.sh | ||
| gotool-packages.txt | ||
| libgo-packages.txt | ||
| libgo.imp | ||
| match.sh | ||
| merge.sh | ||
| mkrsysinfo.sh | ||
| mkruntimeinc.sh | ||
| mksigtab.sh | ||
| mksysinfo.sh | ||
| mvifdiff.sh | ||
| sysinfo.c | ||
README
See ../README. This is the runtime support library for the Go programming language. This library is intended for use with the Go frontend. This library should not be stripped when it is installed. Go code relies on being able to look up file/line information, which comes from the debugging info using the libbacktrace library. The library has only been tested on GNU/Linux using glibc, and on Solaris. It should not be difficult to port to other operating systems. Directories: go A copy of the Go library from http://golang.org/, with several changes for gccgo. runtime Runtime functions, written in C, which are called directly by the compiler or by the library. Contributing ============ To contribute patches to the files in this directory, please see http://golang.org/doc/gccgo_contribute.html . The master copy of these files is hosted at http://code.google.com/p/gofrontend . Changes to these files require signing a Google contributor license agreement. If you are the copyright holder, you will need to agree to the individual contributor license agreement at http://code.google.com/legal/individual-cla-v1.0.html. This agreement can be completed online. If your organization is the copyright holder, the organization will need to agree to the corporate contributor license agreement at http://code.google.com/legal/corporate-cla-v1.0.html. If the copyright holder for your code has already completed the agreement in connection with another Google open source project, it does not need to be completed again.