From 875cdfbb543a93950571891898569bb67e78de27 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Wed, 28 Oct 2009 19:28:57 +0000 Subject: [PATCH] * dwarf2-frame.c (dwarf2_build_frame_info): Discard --gc-section leftover FDEs. --- gdb/ChangeLog | 5 ++++ gdb/dwarf2-frame.c | 64 +++++++++++++++++++++++++++++++++++----------- 2 files changed, 54 insertions(+), 15 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index c0809007d01..a58386dcc7d 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2009-10-28 Pedro Alves + + * dwarf2-frame.c (dwarf2_build_frame_info): Discard --gc-section + leftover FDEs. + 2009-10-28 Pedro Alves * infrun.c (keep_going): Wrap with resume_cleanups. diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c index 5e9be2ccb2c..a4d6dd53596 100644 --- a/gdb/dwarf2-frame.c +++ b/gdb/dwarf2-frame.c @@ -2101,7 +2101,9 @@ dwarf2_build_frame_info (struct objfile *objfile) if (fde_table.num_entries != 0) { struct dwarf2_fde_table *fde_table2; - int i, j; + struct dwarf2_fde *fde_prev = NULL; + struct dwarf2_fde *first_non_zero_fde = NULL; + int i; /* Prepare FDE table for lookups. */ qsort (fde_table.entries, fde_table.num_entries, @@ -2110,22 +2112,54 @@ dwarf2_build_frame_info (struct objfile *objfile) /* Copy fde_table to obstack: it is needed at runtime. */ fde_table2 = (struct dwarf2_fde_table *) obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2)); + fde_table2->num_entries = 0; + + /* Check for leftovers from --gc-sections. The GNU linker sets + the relevant symbols to zero, but doesn't zero the FDE *end* + ranges because there's no relocation there. It's (offset, + length), not (start, end). On targets where address zero is + just another valid address this can be a problem, since the + FDEs appear to be non-empty in the output --- we could pick + out the wrong FDE. To work around this, when overlaps are + detected, we prefer FDEs that do not start at zero. + + Start by finding the first FDE with non-zero start. Below + we'll discard all FDEs that start at zero and overlap this + one. */ + for (i = 0; i < fde_table.num_entries; i++) + { + struct dwarf2_fde *fde = fde_table.entries[i]; - /* Since we'll be doing bsearch, squeeze out identical (except for - eh_frame_p) fde entries so bsearch result is predictable. */ - for (i = 0, j = 0; j < fde_table.num_entries; ++i) - { - const int k = j; - - obstack_grow (&objfile->objfile_obstack, &fde_table.entries[j], - sizeof (fde_table.entries[0])); - while (++j < fde_table.num_entries - && (fde_table.entries[k]->initial_location - == fde_table.entries[j]->initial_location)) - /* Skip. */; - } + if (fde->initial_location != 0) + { + first_non_zero_fde = fde; + break; + } + } + + /* Since we'll be doing bsearch, squeeze out identical (except + for eh_frame_p) fde entries so bsearch result is predictable. + Also discard leftovers from --gc-sections. */ + for (i = 0; i < fde_table.num_entries; i++) + { + struct dwarf2_fde *fde = fde_table.entries[i]; + + if (fde->initial_location == 0 + && first_non_zero_fde != NULL + && (first_non_zero_fde->initial_location + < fde->initial_location + fde->address_range)) + continue; + + if (fde_prev != NULL + && fde_prev->initial_location == fde->initial_location) + continue; + + obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i], + sizeof (fde_table.entries[0])); + ++fde_table2->num_entries; + fde_prev = fde; + } fde_table2->entries = obstack_finish (&objfile->objfile_obstack); - fde_table2->num_entries = i; set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2); /* Discard the original fde_table. */ -- 2.30.2