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96fda643d0
The configure checks for sigcontext (aka sigcontext_struct) have failed
for a long time without anyone noticing. The MR_GET_FAULT_ADDR macro
that is also needed for the sigcontext code paths was only ever defined
for __i386__ and __mc68000__.
According to the sigaction(2) man page, the struct sigcontext
argument was obsoleted by the introduction of the SA_SIGINFO flag
(which we also have code for, though also not working either).
configure.ac:
Delete checks related to struct sigcontext.
Delete check for asm/sigcontext.h
runtime/mercury_conf.h.in:
Delete macros that are no longer defined.
runtime/mercury_memory_handlers.c:
runtime/mercury_signal.c:
runtime/mercury_signal.h:
Delete code for using signal handlers that take a sigcontext argument.
Add XXX where native GC casts a context parameter to
struct sigcontext * when it should be a ucontext_t *.
Possibly never tested.
runtime/mercury_faultaddr.h:
Delete this file containing only the MR_GET_FAULT_ADDR macro which is
no longer used.
runtime/RESERVED_MACRO_NAMES:
ssdb/RESERVED_MACRO_NAMES:
trace/RESERVED_MACRO_NAMES:
Delete macros that are no longer defined.
tools/configure_mingw_cross:
Don't need to set variables mercury_cv_sigcontext_struct_2arg and
mercury_cv_sigcontext_struct_3arg any more.
This directory holds the trace subsystem, i.e. the part of the Mercury debugger that is written in C code. Notes on interfacing with other subsystems ------------------------------------------ If tracing is enabled, the compiler includes calls to MR_trace() in the generated C code. The trace subsystem in this directory is therefore called directly from Mercury code, via MR_trace() in runtime/mercury_trace_base.c. One of the first things it does is to save the original values of the Mercury registers in a variable called `saved_regs'. The reason it needs to do this is that the code here may modify registers, e.g. by allocating memory using incr_hp or by calling Mercury code. Once the original values of the registers have been saved, the trace subsystem is free to modify the Mercury registers. So for all code in this directory, the usual convention is that the original values of the Mercury registers are in `saved_regs', while the current (scratch) values for the normal non-transient Mercury registers etc. are in their normal locations, not in the fake_reg copies, and the transient (register window) registers, if any, are in the fake_reg copies. Any code which uses macros such as incr_hp(), list_cons(), make_aligned_string(), etc. that modify the heap pointer must call restore_transient_regs() beforehand and must call save_transient_regs() afterwards. The simplest way to do this is to use the macro MR_TRACE_USE_HP() in trace/mercury_trace_util.h. The tracer may invoke Mercury code defined in the browser or library directories if that code is exported to C using `pragma export'. But any calls from functions here to code defined in Mercury and exported using `pragma export', i.e. functions starting with `ML_' prefixes, must be preceded by a call to save_registers() and followed by a call to restore_registers(). The simplest way to do this is to use the macro MR_TRACE_CALL_MERCURY() in trace/mercury_trace_util.h.