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authorMark Kettenis <kettenis@gnu.org>2001-03-28 11:36:23 +0000
committerMark Kettenis <kettenis@gnu.org>2001-03-28 11:36:23 +0000
commit9c910f2f54d9671b100bc9ce9698d283c1bc214c (patch)
tree930dbfb17fbbbc422cff5cd71a868cd65907dc49 /gdb/i386-linux-tdep.c
parent0dcb8b8253b3ae6763937bcb59473e510793af30 (diff)
downloadgdb-9c910f2f54d9671b100bc9ce9698d283c1bc214c.tar.gz
* i386-linux-tdep.c (FRAMELESS_SIGNAL): Moved here from
config/i386/nm-linux.h (including comment). (i386_linux_frame_chain): New function implementing guts of the former FRAME_CHAIN macro, but using read_memory_unsigned_integer instead of read_memory_integer. (i386_linux_frame_saved_pc): Removed doc pointing to i386/tm-linux.h for an explanation of FRAMELESS_SIGNAL since that now lives in this file. * config/i386/tm-linux.h (FRAMELESS_SIGNAL): Moved to i386-linux-tdep.c (including comment). (FRAME_CHAIN): Redefined in terms of i386_linux_frame_chain. (i386_linux_frame_chain): New prototype.
Diffstat (limited to 'gdb/i386-linux-tdep.c')
-rw-r--r--gdb/i386-linux-tdep.c44
1 files changed, 38 insertions, 6 deletions
diff --git a/gdb/i386-linux-tdep.c b/gdb/i386-linux-tdep.c
index 56a5eadecd9..f98801b4d0c 100644
--- a/gdb/i386-linux-tdep.c
+++ b/gdb/i386-linux-tdep.c
@@ -277,6 +277,44 @@ i386_linux_sigtramp_saved_sp (struct frame_info *frame)
return read_memory_integer (addr + LINUX_SIGCONTEXT_SP_OFFSET, 4);
}
+/* Signal trampolines don't have a meaningful frame. As in
+ "i386/tm-i386.h", the frame pointer value we use is actually the
+ frame pointer of the calling frame -- that is, the frame which was
+ in progress when the signal trampoline was entered. GDB mostly
+ treats this frame pointer value as a magic cookie. We detect the
+ case of a signal trampoline by looking at the SIGNAL_HANDLER_CALLER
+ field, which is set based on IN_SIGTRAMP.
+
+ When a signal trampoline is invoked from a frameless function, we
+ essentially have two frameless functions in a row. In this case,
+ we use the same magic cookie for three frames in a row. We detect
+ this case by seeing whether the next frame has
+ SIGNAL_HANDLER_CALLER set, and, if it does, checking whether the
+ current frame is actually frameless. In this case, we need to get
+ the PC by looking at the SP register value stored in the signal
+ context.
+
+ This should work in most cases except in horrible situations where
+ a signal occurs just as we enter a function but before the frame
+ has been set up. */
+
+#define FRAMELESS_SIGNAL(frame) \
+ ((frame)->next != NULL \
+ && (frame)->next->signal_handler_caller \
+ && frameless_look_for_prologue (frame))
+
+CORE_ADDR
+i386_linux_frame_chain (struct frame_info *frame)
+{
+ if (frame->signal_handler_caller || FRAMELESS_SIGNAL (frame))
+ return frame->frame;
+
+ if (! inside_entry_file (frame->pc))
+ return read_memory_unsigned_integer (frame->frame, 4);
+
+ return 0;
+}
+
/* Return the saved program counter for FRAME. */
CORE_ADDR
@@ -285,11 +323,6 @@ i386_linux_frame_saved_pc (struct frame_info *frame)
if (frame->signal_handler_caller)
return i386_linux_sigtramp_saved_pc (frame);
- /* See comment in "i386/tm-linux.h" for an explanation what this
- "FRAMELESS_SIGNAL" stuff is supposed to do.
-
- FIXME: kettenis/2001-03-26: That comment should eventually be
- moved to this file. */
if (FRAMELESS_SIGNAL (frame))
{
CORE_ADDR sp = i386_linux_sigtramp_saved_sp (frame->next);
@@ -309,7 +342,6 @@ i386_linux_saved_pc_after_call (struct frame_info *frame)
return read_memory_integer (read_register (SP_REGNUM), 4);
}
-
/* Calling functions in shared libraries. */