diff options
| author | Ian Lance Taylor <iant@golang.org> | 2015-12-11 17:16:48 -0800 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2016-04-01 04:13:44 +0000 |
| commit | ea306ae625d001a43ef20163739593a21be51f97 (patch) | |
| tree | 9123485cd4112995217584ee66e39c6f584533b2 /src/runtime/sys_linux_amd64.s | |
| parent | b64f549ba95fb9115afb1db8ae594b9442c45a6e (diff) | |
| download | go-ea306ae625d001a43ef20163739593a21be51f97.tar.xz | |
runtime: support symbolic backtrace of C code in a cgo crash
The new function runtime.SetCgoTraceback may be used to register stack
traceback and symbolizer functions, written in C, to do a stack
traceback from cgo code.
There is a sample implementation of runtime.SetCgoSymbolizer at
github.com/ianlancetaylor/cgosymbolizer. Just importing that package is
sufficient to get symbolic C backtraces.
Currently only supported on linux/amd64.
Change-Id: If96ee2eb41c6c7379d407b9561b87557bfe47341
Reviewed-on: https://go-review.googlesource.com/17761
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/sys_linux_amd64.s')
| -rw-r--r-- | src/runtime/sys_linux_amd64.s | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/src/runtime/sys_linux_amd64.s b/src/runtime/sys_linux_amd64.s index 7cab649238..031e412673 100644 --- a/src/runtime/sys_linux_amd64.s +++ b/src/runtime/sys_linux_amd64.s @@ -234,8 +234,65 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$24 CALL AX RET +// Used instead of sigtramp in programs that use cgo. +// Arguments from kernel are in DI, SI, DX. +TEXT runtime·cgoSigtramp(SB),NOSPLIT,$0 + // If no traceback function, do usual sigtramp. + MOVQ runtime·cgoTraceback(SB), AX + TESTQ AX, AX + JZ sigtramp + + // If no traceback support function, which means that + // runtime/cgo was not linked in, do usual sigtramp. + MOVQ _cgo_callers(SB), AX + TESTQ AX, AX + JZ sigtramp + + // Figure out if we are currently in a cgo call. + // If not, just do usual sigtramp. + get_tls(CX) + MOVQ g(CX),AX + TESTQ AX, AX + JZ sigtramp // g == nil + MOVQ g_m(AX), AX + TESTQ AX, AX + JZ sigtramp // g.m == nil + MOVL m_ncgo(AX), CX + TESTL CX, CX + JZ sigtramp // g.m.ncgo == 0 + MOVQ m_curg(AX), CX + TESTQ CX, CX + JZ sigtramp // g.m.curg == nil + MOVQ g_syscallsp(CX), CX + TESTQ CX, CX + JZ sigtramp // g.m.curg.syscallsp == 0 + MOVQ m_cgoCallers(AX), R8 + TESTQ R8, R8 + JZ sigtramp // g.m.cgoCallers == nil + MOVL m_cgoCallersUse(AX), CX + TESTL CX, CX + JNZ sigtramp // g.m.cgoCallersUse != 0 + + // Jump to a function in runtime/cgo. + // That function, written in C, will call the user's traceback + // function with proper unwind info, and will then call back here. + // The first three arguments are already in registers. + // Set the last three arguments now. + MOVQ runtime·cgoTraceback(SB), CX + MOVQ $runtime·sigtramp(SB), R9 + MOVQ _cgo_callers(SB), AX + JMP AX + +sigtramp: + JMP runtime·sigtramp(SB) + +// For cgo unwinding to work, this function must look precisely like +// the one in glibc. The glibc source code is: +// https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/x86_64/sigaction.c +// The code that cares about the precise instructions used is: +// https://gcc.gnu.org/viewcvs/gcc/trunk/libgcc/config/i386/linux-unwind.h?revision=219188&view=markup TEXT runtime·sigreturn(SB),NOSPLIT,$0 - MOVL $15, AX // rt_sigreturn + MOVQ $15, AX // rt_sigreturn SYSCALL INT $3 // not reached |