Changes for v4:
- Since __libdwfl_set_initial_registers_thread is now private to
libdwfl, the modified code in this patch has been disabled.
* * *
Dummy commit to show how the sample_set_initial_registers callback in
eu-stacktrace would use the proper libebl
ebl_set_initial_registers_sample function (if it were public).
* src/Makefile.am (stacktrace_LDADD): Add libebl.
* src/stacktrace.c (sample_registers_cb): New function,
though identical to pid_thread_state_registers_cb.
(sample_set_initial_registers): (XXX Invoke
ebl_set_initial_registers_sample instead of containing
platform-specific code directly. This is now commented out.
Patch12 in the series replaces with code in
libdwfl_stacktrace/dwflst_perf_frame.c.)
---
src/Makefile.am | 4 ++--
src/stacktrace.c | 34 +++++++++++++++++++++++++++++-----
2 files changed, 31 insertions(+), 7 deletions(-)
diff --git a/src/Makefile.am b/src/Makefile.am
index ed245fc1..6d713e88 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
## Process this file with automake to create Makefile.in
##
-## Copyright (C) 1996-2014, 2016, 2024 Red Hat, Inc.
+## Copyright (C) 1996-2014, 2016, 2024-2025 Red Hat, Inc.
## This file is part of elfutils.
##
## This file is free software; you can redistribute it and/or modify
@@ -105,7 +105,7 @@ ar_LDADD = libar.a $(libelf) $(libeu) $(argp_LDADD)
$(obstack_LIBS)
unstrip_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
stack_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
$(demanglelib)
if ENABLE_STACKTRACE
-stacktrace_LDADD = $(libelf) $(libdw) $(libeu) $(argp_LDADD)
+stacktrace_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
endif
elfcompress_LDADD = $(libebl) $(libelf) $(libdw) $(libeu) $(argp_LDADD)
elfclassify_LDADD = $(libelf) $(libdw) $(libeu) $(argp_LDADD)
diff --git a/src/stacktrace.c b/src/stacktrace.c
index d8699ce5..3f5950fb 100644
--- a/src/stacktrace.c
+++ b/src/stacktrace.c
@@ -1,5 +1,5 @@
/* Process a stream of stack samples into stack traces.
- Copyright (C) 2023-2024 Red Hat, Inc.
+ Copyright (C) 2023-2025 Red Hat, Inc.
This file is part of elfutils.
This file is free software; you can redistribute it and/or modify
@@ -93,9 +93,11 @@
* Includes: libdwfl data structures *
*************************************/
+#include ELFUTILS_HEADER(ebl)
/* #include ELFUTILS_HEADER(dwfl) */
#include "../libdwfl/libdwflP.h"
-/* XXX: Private header needed for find_procfile, sysprof_init_dwfl */
+/* XXX: Private header needed for find_procfile, sysprof_init_dwfl,
+ sample_set_initial_registers. */
/*************************************
* Includes: sysprof data structures *
@@ -574,10 +576,31 @@ sample_memory_read (Dwfl *dwfl, Dwarf_Addr addr,
Dwarf_Word *result, void *arg)
return true;
}
-/* TODO: Need to generalize this code beyond x86 architectures. */
static bool
-sample_set_initial_registers (Dwfl_Thread *thread, void *thread_arg)
+sample_set_initial_registers (Dwfl_Thread *thread, void *arg)
{
+#if 0
+ /* TODO: __libdwfl_set_initial_registers_thread not exported from libdwfl,
+ after it was decided to be unsuitable for a public API.
+
+ A subsequent patch in the series removes sample_set_initial_registers,
+ replacing it with code in libdwfl_stacktrace/dwflst_perf_frame.c.
+ Keeping this code commented-out for the record, cf how we would
+ implement if the set_initial_registers utility func was public.
+
+ To *actually* make this work, would need to copy the set_initial_registers
+ implementation into stacktrace.c; not worth doing since the later patch
+ overrides this code. */
+ struct __sample_arg *sample_arg = (struct __sample_arg *)arg;
+ dwfl_thread_state_register_pc (thread, sample_arg->pc);
+ Dwfl_Process *process = thread->process;
+ Ebl *ebl = process->ebl;
+ /* XXX Sysprof provides exactly the required registers for unwinding: */
+ uint64_t regs_mask = ebl_perf_frame_regs_mask (ebl);
+ return ebl_set_initial_registers_sample
+ (ebl, sample_arg->regs, sample_arg->n_regs, regs_mask, sample_arg->abi,
+ __libdwfl_set_initial_registers_thread, thread);
+#else
/* The following facts are needed to translate x86 registers correctly:
- perf register order seen in linux arch/x86/include/uapi/asm/perf_regs.h
The registers array is built in the same order as the enum!
@@ -592,7 +615,7 @@ sample_set_initial_registers (Dwfl_Thread *thread, void
*thread_arg)
For comparison, you can study
codereview.qt-project.org/gitweb?p=qt-creator/perfparser.git;a=blob;f=app/perfregisterinfo.cpp;hb=HEAD
and follow the code which uses those tables of magic numbers.
But it's better to follow original sources of truth for this. */
- struct __sample_arg *sample_arg = (struct __sample_arg *)thread_arg;
+ struct __sample_arg *sample_arg = (struct __sample_arg *)arg;
bool is_abi32 = (sample_arg->abi == PERF_SAMPLE_REGS_ABI_32);
static const int regs_i386[] = {0, 2, 3, 1, 7/*sp*/, 6, 4, 5, 8/*ip*/};
static const int regs_x86_64[] = {0, 3, 2, 1, 4, 5, 6, 7/*sp*/, 9, 10, 11,
12, 13, 14, 15, 16, 8/*ip*/};
@@ -610,6 +633,7 @@ sample_set_initial_registers (Dwfl_Thread *thread, void
*thread_arg)
dwfl_thread_state_registers (thread, i, 1, &sample_arg->regs[j]);
}
return true;
+#endif
}
static void
--
2.47.0
