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authorAndrew Burgess <andrew.burgess@embecosm.com>2020-01-11 01:38:28 +0000
committerAndrew Burgess <andrew.burgess@embecosm.com>2020-01-24 00:10:33 +0000
commit733d0a679536628eb1be4b4b8aa6384de24ff1f1 (patch)
tree9a8f6e77b400a79b40433763852d33b78e77b423 /gdb/minsyms.c
parent2f267673f0fdee9287e6d404ecd4f2d29da0d2f2 (diff)
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gdb/tui: asm window handles invalid memory and scrolls better
This started as a patch to enable the asm window to handle attempts to disassemble invalid memory, but it ended up expanding into a significant rewrite of how the asm window handles scrolling. These two things ended up being tied together as it was impossible to correctly test scrolling into invalid memory when the asm window would randomly behave weirdly while scrolling. Things that should work nicely now; scrolling to the bottom or top of the listing with PageUp, PageDown, Up Arrow, Down Arrow and we should be able to scroll past small areas of memory that don't have symbols associated with them. It should also be possible to scroll to the start of a section even if there's no symbol at the start of the section. Adding tests for this scrolling was a little bit of a problem. First I would have liked to add tests for PageUp / PageDown, but the tuiterm library we use doesn't support these commands right now due to only emulating a basic ascii terminal. Changing this to emulate a more complex terminal would require adding support for more escape sequence control codes, so I've not tried to tackle that in this patch. Next, I would have liked to test scrolling to the start or end of the assembler listing and then trying to scroll even more, however, this is a problem because in a well behaving GDB a scroll at the start/end has no effect. What we need to do is: - Move to start of assembler listing, - Send scroll up command, - Wait for all curses output, - Ensure the assembler listing is unchanged, we're still at the start of the listing. The problem is that there is no curses output, so how long do we wait at step 3? The same problem exists for scrolling to the bottom of the assembler listing. However, when scrolling down you can at least see the end coming, so I added a test for this case, however, this feels like an area of code that is massively under tested. gdb/ChangeLog: PR tui/9765 * minsyms.c (lookup_minimal_symbol_by_pc_section): Update header comment, add extra parameter, and update to store previous symbol when appropriate. * minsyms.h (lookup_minimal_symbol_by_pc_section): Update comment, add extra parameter. * tui/tui-disasm.c (tui_disassemble): Update header comment, remove unneeded parameter, add try/catch around gdb_print_insn, rewrite to add items to asm_lines vector. (tui_find_backward_disassembly_start_address): New function. (tui_find_disassembly_address): Updated throughout. (tui_disasm_window::set_contents): Update for changes to tui_disassemble. (tui_disasm_window::do_scroll_vertical): No need to adjust the number of lines to scroll. gdb/testsuite/ChangeLog: PR tui/9765 * gdb.tui/tui-layout-asm.exp: Add scrolling test for asm window. Change-Id: I323987c8fd316962c937e73c17d952ccd3cfa66c
Diffstat (limited to 'gdb/minsyms.c')
-rw-r--r--gdb/minsyms.c41
1 files changed, 28 insertions, 13 deletions
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 2133508..e238355 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -666,24 +666,18 @@ msym_prefer_to_msym_type (lookup_msym_prefer prefer)
gdb_assert_not_reached ("unhandled lookup_msym_prefer");
}
-/* Search through the minimal symbol table for each objfile and find
- the symbol whose address is the largest address that is still less
- than or equal to PC, and matches SECTION (which is not NULL).
- Returns a pointer to the minimal symbol if such a symbol is found,
- or NULL if PC is not in a suitable range.
+/* See minsyms.h.
+
Note that we need to look through ALL the minimal symbol tables
before deciding on the symbol that comes closest to the specified PC.
This is because objfiles can overlap, for example objfile A has .text
at 0x100 and .data at 0x40000 and objfile B has .text at 0x234 and
- .data at 0x40048.
-
- If WANT_TRAMPOLINE is set, prefer mst_solib_trampoline symbols when
- there are text and trampoline symbols at the same address.
- Otherwise prefer mst_text symbols. */
+ .data at 0x40048. */
bound_minimal_symbol
lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *section,
- lookup_msym_prefer prefer)
+ lookup_msym_prefer prefer,
+ bound_minimal_symbol *previous)
{
int lo;
int hi;
@@ -693,6 +687,12 @@ lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *sectio
struct objfile *best_objfile = NULL;
struct bound_minimal_symbol result;
+ if (previous != nullptr)
+ {
+ previous->minsym = nullptr;
+ previous->objfile = nullptr;
+ }
+
if (section == NULL)
{
section = find_pc_section (pc_in);
@@ -886,8 +886,23 @@ lookup_minimal_symbol_by_pc_section (CORE_ADDR pc_in, struct obj_section *sectio
if (best_zero_sized != -1)
hi = best_zero_sized;
else
- /* Go on to the next object file. */
- continue;
+ {
+ /* If needed record this symbol as the closest
+ previous symbol. */
+ if (previous != nullptr)
+ {
+ if (previous->minsym == nullptr
+ || (MSYMBOL_VALUE_RAW_ADDRESS (&msymbol[hi])
+ > MSYMBOL_VALUE_RAW_ADDRESS
+ (previous->minsym)))
+ {
+ previous->minsym = &msymbol[hi];
+ previous->objfile = objfile;
+ }
+ }
+ /* Go on to the next object file. */
+ continue;
+ }
}
/* The minimal symbol indexed by hi now is the best one in this