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89 lines
3.3 KiB
89 lines
3.3 KiB
6 years ago
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commit 62261490a36c6911c5eb61be7cddcfb1bd19ba18
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Author: Pedro Alves <palves@redhat.com>
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Date: Thu Jan 16 17:43:26 2014 +0000
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Fix gdb.trace/mi-traceframe-changed.exp on s390.
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The test fails on s390 with:
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-trace-find frame-number 0^M
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&"PC not available\n"^M
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^done,found="1",tracepoint="1",traceframe="0",frame={level="-1",addr="<unavailable>",func="??",args=[]}^M
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(gdb) ^M
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FAIL: gdb.trace/mi-traceframe-changed.exp: tfile: -trace-find frame-number 0
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tfile knows to infer the PC from the tracepoint's address if the PC
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wasn't collected (tfile_fetch_registers) but, that only works on
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targets whose PC register is a raw register, and on s390, the PC
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register is a pseudo register.
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But even if GDB doesn't know how to infer the value of PC, saying the
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current frame is level -1 is a bug:
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^done,found="1",tracepoint="1",traceframe="0",frame={level="-1",addr="<unavailable>",func="??",args=[]}^M
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^^^^^^^^^
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'-1' is the level of the sentinel frame, which should never be visible.
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This is caused by the s390's heuristic unwinder accepting the frame
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(the fallback heuristic unwinders _always_ accept the frame), but then
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the unwind->this_id method throws that "PC not available\n" error.
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IOW, the s390's heuristic unwinder was never adjusted to handle
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unavailable register values gracefully, which can happen with e.g., a
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trimmed core file too.
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This is just the minimal necessary for
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<unavailable> frames, which at least gets us:
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(gdb) tfind
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Found trace frame 0, tracepoint 1
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#0 <unavailable> in ?? ()
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That is, frame #0 instead of -1.
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We could get better info out of "info frame" (this patch makes us show
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"outermost"), but this change would still be necessary.
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gdb/
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2014-01-16 Pedro Alves <palves@redhat.com>
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* s390-linux-tdep.c (s390_frame_unwind_cache): Swallow
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NOT_AVAILABLE_ERROR errors while parsing the prologue or reading
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the backchain.
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Index: gdb-7.6.1/gdb/s390-tdep.c
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===================================================================
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--- gdb-7.6.1.orig/gdb/s390-tdep.c
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+++ gdb-7.6.1/gdb/s390-tdep.c
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@@ -1995,7 +1995,9 @@ static struct s390_unwind_cache *
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s390_frame_unwind_cache (struct frame_info *this_frame,
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void **this_prologue_cache)
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{
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+ volatile struct gdb_exception ex;
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struct s390_unwind_cache *info;
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+
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if (*this_prologue_cache)
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return *this_prologue_cache;
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@@ -2006,10 +2008,15 @@ s390_frame_unwind_cache (struct frame_in
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info->frame_base = -1;
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info->local_base = -1;
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- /* Try to use prologue analysis to fill the unwind cache.
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- If this fails, fall back to reading the stack backchain. */
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- if (!s390_prologue_frame_unwind_cache (this_frame, info))
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- s390_backchain_frame_unwind_cache (this_frame, info);
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+ TRY_CATCH (ex, RETURN_MASK_ERROR)
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+ {
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+ /* Try to use prologue analysis to fill the unwind cache.
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+ If this fails, fall back to reading the stack backchain. */
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+ if (!s390_prologue_frame_unwind_cache (this_frame, info))
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+ s390_backchain_frame_unwind_cache (this_frame, info);
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+ }
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+ if (ex.reason < 0 && ex.error != NOT_AVAILABLE_ERROR)
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+ throw_exception (ex);
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return info;
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}
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