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2013-11-24set/show code-cacheYao Qi8-5/+118
Similar to stack cache, in this patch, we add TARGET_OBJECT_CODE_MEMORY to read code from target and add a new option "set code-cache on|off" to optimize code accesses by using the target memory cache. In V4: - Remove "without affecting correctness" from NEWS and doc. - Replace "ON" with "on" in doc. - "access" -> "accesses". In V3: - Rename functions and variables. - Update command help, doc and NEWS entry. - Invalidate cache on option transitions, to align with the behaviour of "stack-cache". Since cache invalidation is transparent to users, users don't know option "stack-cache" transitions cause code cache invalidation. V2 was reviewed by Doug. There are some changes in V3, so I post it here. gdb: 2013-11-24 Yao Qi <yao@codesourcery.com> * NEWS: Add note on new "set code-cache" option. * target-dcache.c (code_cache_enabled_1): New variable. (code_cache_enabled): New variable. (show_code_cache, set_code_cache): New function. (code_cache_enabled_p): New function. (_initialize_target_dcache): Register command. * target-dcache.h (code_cache_enabled_p): Declare. * target.c (memory_xfer_partial_1):Handle TARGET_OBJECT_CODE_MEMORY and code_cache_enabled. (target_read_code): New function. * target.h (enum target_object) <TARGET_OBJECT_CODE_MEMORY>: New. (target_read_code): Declare. gdb/doc: 2013-11-24 Yao Qi <yao@codesourcery.com> * gdb.texinfo (Caching Remote Data): Document new "set/show stack-cache" option.
2013-11-24Renaming in target-dcache.cYao Qi4-18/+34
Hi, This patch does some renamings on "stack-cache" related functions and variables. In the review to "code cache" series v2, we have some discussions on the name of predicate function 'stack_cache_enabled', and have some options, 1 keep it unchanged, as it is already a predicate clearly, 2 rename it to stack_cache_enabled_p, 3 rename it to enable_stack_cache_p, I choose #2, because 'stack_cache_enabled' is a predicate, but it's better to add "_p" suffix to stress this. There are some other similar patterns used in GDB source, such as unop_user_defined_p and agent_loaded_p. Then, I have to rename variable stack_cache_enabled_p to something else. The option is "stack-cache", so I'd like to name the variable associated with this command as "stack_cache". Similarly, the commands associated with this command should be renamed to "set_stack_cache" and "show_stack_cache" respectively. gdb: 2013-11-24 Yao Qi <yao@codesourcery.com> * target-dcache.c (stack_cache_enabled_p_1): Rename to ... (stack_cache_enabled_1): ... this. New variable. (stack_cache_enabled_p): Rename to ... (stack_cache_enabled): ... this. New variable. (set_stack_cache_enabled_p): Rename to ... (set_stack_cache): ... this. Update caller. (show_stack_cache_enabled_p): Rename to ... (show_stack_cache): ... this. Update caller. (stack_cache_enabled): Rename to ... (stack_cache_enabled_p): ... this. Update caller. (_initialize_target_dcache): Replace "data cache" with "target memory cache". * target-dcache.h (stack_cache_enabled): Remove declaration. (stack_cache_enabled_p): Add declaration.
2013-11-24GDB perf test on single stepYao Qi4-0/+131
gdb/testsuite: 2013-11-24 Yao Qi <yao@codesourcery.com> * gdb.perf/single-step.c: New. * gdb.perf/single-step.exp: New. * gdb.perf/single-step.py: New.
2013-11-24Write "ON" and "OFF" in lower case in GDB doc.Yao Qi2-3/+9
gdb/doc: 2013-11-24 Yao Qi <yao@codesourcery.com> * gdb.texinfo (Caching Target Data): Replace "ON" with "on". (Maintenance Commands): Replace "ON" and "OFF" with "on" and "off" respectively.
2013-11-23 * gdb.base/ena-dis-br.exp: Add missing quote to "step after continueDoug Evans2-1/+6
with ignore count".
2013-11-23Test name tweaks for py-value.exp.Doug Evans2-5/+13
* gdb.python/py-value.exp (test_lazy_strings): Tweak test names. (test_subscript_regression): Ditto. (top level): Run test_subscript_regression for c++ with "c++" prefix.
2013-11-23 * gdb.python/py-type.exp (test_enums): Fix typo.Doug Evans2-1/+6
2013-11-23* gdb.python/py-symbol.exp: Add some comments. Make all test names unique.Doug Evans2-16/+34
2013-11-23* gdb.python/py-symbol.exp: Fix whitespace.Doug Evans2-4/+8
2013-11-23Fix long line in earlier entry.Doug Evans1-2/+2
2013-11-23 * gdb.python/python.exp: Don't call skip_python_tests, we still wantDoug Evans2-3/+7
to test some things in the case where python is not configured in.
2013-11-24daily updateAlan Modra1-1/+1
2013-11-23 * python/py-frame.c (gdbpy_initialize_frames): Remove FIRST_ERROR,Doug Evans2-4/+5
superfluous.
2013-11-23 * python/py-frame.c (frapy_block): Fix error message text.Doug Evans2-1/+5
2013-11-23cli/cli-script.c (multi_line_command_p): New function.Doug Evans2-15/+31
* cli/cli-script.c (multi_line_command_p): New function. (recurse_read_control_structure, read_command_lines_1): Call it. (execute_control_command): Consistently have a blank line between each case.
2013-11-23Update doc on displayhint in command -var-list-childrenYao Qi2-0/+10
Hi, When using command -var-list-children, "displayhint" appears in the result of each child, shown as the following output. -var-list-children ss1 ^M ^done,numchild="2",displayhint="pp_ss",children=[child={name="ss1.a",exp="a",numchild="0",type="struct s",thread-id="1",displayhint="pp_s",dynamic="1"},child={name="ss1.b",exp="b",numchild="0",type="struct s",thread-id="1",displayhint="pp_s",dynamic="1"}],has_more="0" Current doc on command -var-list-children doesn't reflect this. This patch is to fix it. gdb/doc: 2013-11-23 Yao Qi <yao@codesourcery.com> * gdb.texinfo (GDB/MI Variable Objects): Add the description of "displayhint" to the table about child results.
2013-11-22Add check for which library is needed for dlopen.Cary Coutant3-5/+74
gold/ PR gold/16203 * configure.ac: Add check for which library is needed for dlopen. * configure: Regenerate.
2013-11-22Use in-tree assembler for exception_x86_64_bnd_test.Cary Coutant3-4/+10
gold/ * testsuite/Makefile.am (exception_x86_64_bnd_test): Use in-tree assembler. * testsuite/Makefile.in: Regenerate.
2013-11-23daily updateAlan Modra1-1/+1
2013-11-23Import config.sub and config.guess from upstream.Alan Modra3-72/+95
2013-11-222013-11-22 Sterling Augustine <saugustine@google.com>Sterling Augustine1-1/+1
PR gdb/16196: * valprint.c (read_string): Set new variable fetchlen based on fetchlimit and size. Use it in call to partial_memory_read. Update comment.
2013-11-222013-11-22 Sterling Augustine <saugustine@google.com>Sterling Augustine2-7/+18
PR gdb/16196: * valprint.c (read_string): Set new variable fetchlen based on fetchlimit and size. Use it in call to partial_memory_read. Update comment.
2013-11-22Rename gdb.dwarf2/dw2-bad-cfi.* to gdb.dwarf2/dw2-unspecified-ret-addr.*.Pedro Alves4-13/+22
gdb/testsuite/ 2013-11-22 Pedro Alves <palves@redhat.com> * gdb.dwarf2/dw2-bad-cfi.S: Rename to ... * gdb.dwarf2/dw2-unspecified-ret-addr.S: ... this. Adjust. * gdb.dwarf2/dw2-bad-cfi.c: Rename to ... * gdb.dwarf2/dw2-unspecified-ret-addr.c: ... this. * gdb.dwarf2/dw2-bad-cfi.exp: Rename to ... * gdb.dwarf2/dw2-unspecified-ret-addr.exp: ... this.
2013-11-22update comment in dw2-bad-cfi.S.Tom Tromey2-1/+6
Pedro asked me to add a comment to dw2-bad-cfi.S explaining the nature of the badness. I'm checking this in. 2013-11-22 Tom Tromey <tromey@redhat.com> * gdb.dwarf2/dw2-bad-cfi.S: Update comment.
2013-11-22handle an unspecified return address columnTom Tromey6-0/+302
Debugging PR 16155 further, I found that the DWARF unwinder found the function in question, but thought it had no registers saved (fs->regs.num_regs == 0). It seems to me that if a frame does not specify the return address column, or if the return address column is explicitly marked as DWARF2_FRAME_REG_UNSPECIFIED, then we should set the "undefined_retaddr" flag and let the DWARF unwinder gracefully stop. This patch implements that idea. With this patch the backtrace works properly: (gdb) bt #0 0x0000007fb7ed485c in nanosleep () from /lib64/libc.so.6 #1 0x0000007fb7ed4508 in sleep () from /lib64/libc.so.6 #2 0x00000000004008bc in thread_function (arg=0x4) at threadapply.c:73 #3 0x0000007fb7fad950 in start_thread () from /lib64/libpthread.so.0 #4 0x0000007fb7f0956c in clone () from /lib64/libc.so.6 2013-11-22 Tom Tromey <tromey@redhat.com> PR backtrace/16155: * dwarf2-frame.c (dwarf2_frame_cache): Set undefined_retaddr if the return address column is unspecified. 2013-11-22 Tom Tromey <tromey@redhat.com> * gdb.dwarf2/dw2-bad-cfi.c: New file. * gdb.dwarf2/dw2-bad-cfi.exp: New file. * gdb.dwarf2/dw2-bad-cfi.S: New file.
2013-11-22Detect infinite loop in value_fetch_lazy's lval_register handling.Tom Tromey2-1/+26
If value_fetch_lazy loops infinitely while unwrapping lval_register values, it means we either somehow ended up with two frames with the same ID in the frame chain, or some code is trying to unwind behind get_prev_frame's back (e.g., a frame unwind sniffer trying to unwind). In any case, it should always be an internal error to end up in this situation. This patch adds a check and throws an internal error if the same frame is returned. 2013-11-22 Tom Tromey <tromey@redhat.com> Pedro Alves <palves@redhat.com> PR backtrace/16155 * value.c (value_fetch_lazy): Internal error if get_frame_register_value returns the same register.
2013-11-22 * windres.c (define_resource): Use zero for timestamp, makingCory Fields12-44/+72
output deterministic. time.h include is no longer needed. * resres.c (res_append_resource): Likewise. * pe-dll.c (fill_edata): Only use a real timestamp if --insert-timestamp was used. * emultempl/pe.em: Add the --insert-timestamp option. * emultempl/pep.em: Likewise for 64bit. * ld.texinfo: Document the --insert-timestamp option. * libcoff-in.h: Add insert_timestamp flag to the pe_data struct. * libcoff.h: Regenerate. * peXXigen.c (_bfd_XXi_only_swap_filehdr_out): Only use a real timestamp if --insert-timestamp was used.
2013-11-22Make use of the frame stash to detect wider stack cycles.Pedro Alves2-63/+100
Given we already have the frame id stash, which holds the ids of all frames in the chain, detecting corrupted stacks with wide stack cycles with non-consecutive dup frame ids is just as cheap as just detecting cycles in consecutive frames: #0 frame_id1 #1 frame_id2 #2 frame_id3 #3 frame_id1 #4 frame_id2 #5 frame_id3 #6 frame_id1 ... forever ... We just need to check whether the stash already knows about a given frame id instead of comparing the ids of the previous/this frames. Tested on x86_64 Fedora 17. gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> Tom Tromey <tromey@redhat.com> * frame.c (frame_stash_add): Now returns whether a frame with the same ID was already known. (compute_frame_id): New function, factored out from get_frame_id. (get_frame_id): No longer lazilly compute the frame id here. (get_prev_frame_if_no_cycle): New function. Detects wider stack cycles. (get_prev_frame_1): Use it instead of get_prev_frame_raw directly, and checking for stack cycles here.
2013-11-22Don't let two frames with the same id end up in the frame chain.Pedro Alves6-17/+660
The UNWIND_SAME_ID check is done between THIS_FRAME and the next frame when we go try to unwind the previous frame. But at this point, it's already too late -- we ended up with two frames with the same ID in the frame chain. Each frame having its own ID is an invariant assumed throughout GDB. This patch applies the UNWIND_SAME_ID detection earlier, right after the previous frame is unwound, discarding the dup frame if a cycle is detected. The patch includes a new test that fails before the change. Before the patch, the test causes an infinite loop in GDB, after the patch, the UNWIND_SAME_ID logic kicks in and makes the backtrace stop with: Backtrace stopped: previous frame identical to this frame (corrupt stack?) The test uses dwarf CFI to emulate a corrupted stack with a cycle. It has a function with registers marked DW_CFA_same_value (most importantly RSP/RIP), so that GDB computes the same ID for that frame and its caller. IOW, something like this: #0 - frame_id_1 #1 - frame_id_2 #2 - frame_id_3 #3 - frame_id_4 #4 - frame_id_4 <<<< outermost (UNWIND_SAME_ID). (The test's code is just a copy of dw2-reg-undefined.S / dw2-reg-undefined.c, adjusted to use DW_CFA_same_value instead of DW_CFA_undefined, and to mark a different set of registers.) The infinite loop is here, in value_fetch_lazy: while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val)) { frame = frame_find_by_id (VALUE_FRAME_ID (new_val)); ... new_val = get_frame_register_value (frame, regnum); } get_frame_register_value can return a lazy register value pointing to the next frame. This means that the register wasn't clobbered by FRAME; the debugger should therefore retrieve its value from the next frame. To be clear, get_frame_register_value unwinds the value in question from the next frame: struct value * get_frame_register_value (struct frame_info *frame, int regnum) { return frame_unwind_register_value (frame->next, regnum); ^^^^^^^^^^^ } In other words, if we get a lazy lval_register, it should have the frame ID of the _next_ frame, never of FRAME. At this point in value_fetch_lazy, the whole relevant chunk of the stack up to frame #4 has already been unwound. The loop always "unlazies" lval_registers in the "next/innermost" direction, not in the "prev/unwind further/outermost" direction. So say we're looking at frame #4. get_frame_register_value in frame #4 can return a lazy register value of frame #3. So the next iteration, frame_find_by_id tries to read the register from frame #3. But, since frame #4 happens to have same id as frame #3, frame_find_by_id returns frame #4 instead. Rinse, repeat, and we have an infinite loop. This is an old latent problem, exposed by the recent addition of the frame stash. Before we had a stash, frame_find_by_id(frame_id_4) would walk over all frames starting at the current frame, and would always find #3 first. The stash happens to return #4 instead: struct frame_info * frame_find_by_id (struct frame_id id) { struct frame_info *frame, *prev_frame; ... /* Try using the frame stash first. Finding it there removes the need to perform the search by looping over all frames, which can be very CPU-intensive if the number of frames is very high (the loop is O(n) and get_prev_frame performs a series of checks that are relatively expensive). This optimization is particularly useful when this function is called from another function (such as value_fetch_lazy, case VALUE_LVAL (val) == lval_register) which already loops over all frames, making the overall behavior O(n^2). */ frame = frame_stash_find (id); if (frame) return frame; for (frame = get_current_frame (); ; frame = prev_frame) { gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * frame.c (get_prev_frame_1): Do the UNWIND_SAME_ID check between this frame and the new previous frame, not between this frame and the next frame. gdb/testsuite/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * gdb.dwarf2/dw2-dup-frame.S: New file. * gdb.dwarf2/dw2-dup-frame.c: New file. * gdb.dwarf2/dw2-dup-frame.exp: New file.
2013-11-22Eliminate dwarf2_frame_cache recursion, don't unwind from the dwarf2 sniffer ↵Pedro Alves2-15/+32
(move dwarf2_tailcall_sniffer_first elsewhere). Two rationales, same patch. TL;DR 1: dwarf2_frame_cache recursion is evil. dwarf2_frame_cache calls dwarf2_tailcall_sniffer_first which then recurses into dwarf2_frame_cache. TL;DR 2: An unwinder trying to unwind is evil. dwarf2_frame_sniffer calls dwarf2_frame_cache which calls dwarf2_tailcall_sniffer_first which then tries to unwind the PC of the previous frame. Avoid all that by deferring dwarf2_tailcall_sniffer_first until it's really necessary. Rationale 1 =========== A frame sniffer should not try to unwind, because that bypasses all the validation checks done by get_prev_frame. The UNWIND_SAME_ID scenario is one such case where GDB is currently broken because (in part) of this (the next patch adds a test that would fail without this). GDB goes into an infinite loop in value_fetch_lazy, here: while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val)) { frame = frame_find_by_id (VALUE_FRAME_ID (new_val)); ... new_val = get_frame_register_value (frame, regnum); } (top-gdb) bt #0 value_fetch_lazy (val=0x11516d0) at ../../src/gdb/value.c:3510 #1 0x0000000000584bd8 in value_optimized_out (value=0x11516d0) at ../../src/gdb/value.c:1096 #2 0x00000000006fe7a1 in frame_register_unwind (frame=0x1492600, regnum=16, optimizedp=0x7fffffffcdec, unavailablep=0x7fffffffcde8, lvalp=0x7fffffffcdd8, addrp= 0x7fffffffcde0, realnump=0x7fffffffcddc, bufferp=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:940 #3 0x00000000006fea3a in frame_unwind_register (frame=0x1492600, regnum=16, buf=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:990 #4 0x0000000000473b9b in i386_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/i386-tdep.c:1771 #5 0x0000000000601dfa in gdbarch_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/gdbarch.c:2870 #6 0x0000000000693db5 in dwarf2_tailcall_sniffer_first (this_frame=0x1492600, tailcall_cachep=0x14926f0, entry_cfa_sp_offsetp=0x7fffffffcf00) at ../../src/gdb/dwarf2-frame-tailcall.c:389 #7 0x0000000000690928 in dwarf2_frame_cache (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1245 #8 0x0000000000690f46 in dwarf2_frame_sniffer (self=0x8e4980, this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1423 #9 0x000000000070203b in frame_unwind_find_by_frame (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/frame-unwind.c:112 #10 0x00000000006fd681 in get_frame_id (fi=0x1492600) at ../../src/gdb/frame.c:408 #11 0x00000000007006c2 in get_prev_frame_1 (this_frame=0xdc1860) at ../../src/gdb/frame.c:1826 #12 0x0000000000700b7a in get_prev_frame (this_frame=0xdc1860) at ../../src/gdb/frame.c:2056 #13 0x0000000000514588 in frame_info_to_frame_object (frame=0xdc1860) at ../../src/gdb/python/py-frame.c:322 #14 0x000000000051784c in bootstrap_python_frame_filters (frame=0xdc1860, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1396 #15 0x0000000000517a6f in apply_frame_filter (frame=0xdc1860, flags=7, args_type=CLI_SCALAR_VALUES, out=0xed7a90, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1492 #16 0x00000000005e77b0 in backtrace_command_1 (count_exp=0x0, show_locals=0, no_filters=0, from_tty=1) at ../../src/gdb/stack.c:1777 #17 0x00000000005e7c0f in backtrace_command (arg=0x0, from_tty=1) at ../../src/gdb/stack.c:1891 #18 0x00000000004e37a7 in do_cfunc (c=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:107 #19 0x00000000004e683c in cmd_func (cmd=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:1882 #20 0x00000000006f35ed in execute_command (p=0xcc66c2 "", from_tty=1) at ../../src/gdb/top.c:468 #21 0x00000000005f8853 in command_handler (command=0xcc66c0 "bt") at ../../src/gdb/event-top.c:435 #22 0x00000000005f8e12 in command_line_handler (rl=0xfe05f0 "@") at ../../src/gdb/event-top.c:632 #23 0x000000000074d2c6 in rl_callback_read_char () at ../../src/readline/callback.c:220 #24 0x00000000005f8375 in rl_callback_read_char_wrapper (client_data=0x0) at ../../src/gdb/event-top.c:164 #25 0x00000000005f876a in stdin_event_handler (error=0, client_data=0x0) at ../../src/gdb/event-top.c:375 #26 0x00000000005f72fa in handle_file_event (data=...) at ../../src/gdb/event-loop.c:768 #27 0x00000000005f67a3 in process_event () at ../../src/gdb/event-loop.c:342 #28 0x00000000005f686a in gdb_do_one_event () at ../../src/gdb/event-loop.c:406 #29 0x00000000005f68bb in start_event_loop () at ../../src/gdb/event-loop.c:431 #30 0x00000000005f83a7 in cli_command_loop (data=0x0) at ../../src/gdb/event-top.c:179 #31 0x00000000005eeed3 in current_interp_command_loop () at ../../src/gdb/interps.c:327 #32 0x00000000005ef8ff in captured_command_loop (data=0x0) at ../../src/gdb/main.c:267 #33 0x00000000005ed2f6 in catch_errors (func=0x5ef8e4 <captured_command_loop>, func_args=0x0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL) at ../../src/gdb/exceptions.c:524 #34 0x00000000005f0d21 in captured_main (data=0x7fffffffd9e0) at ../../src/gdb/main.c:1067 #35 0x00000000005ed2f6 in catch_errors (func=0x5efb9b <captured_main>, func_args=0x7fffffffd9e0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL) at ../../src/gdb/exceptions.c:524 #36 0x00000000005f0d57 in gdb_main (args=0x7fffffffd9e0) at ../../src/gdb/main.c:1076 #37 0x000000000045bb6a in main (argc=4, argv=0x7fffffffdae8) at ../../src/gdb/gdb.c:34 (top-gdb) GDB is trying to unwind the PC register of the previous frame (frame #5 above), starting from the frame being sniffed (the THIS frame). But the THIS frame's unwinder says the PC of the previous frame is actually the same as the previous's frame's next frame (which is the same frame we started with, the THIS frame), therefore it returns an lval_register lazy value with frame set to THIS frame. And so the value_fetch_lazy loop never ends. Rationale 2 =========== As an experiment, I tried making dwarf2-frame.c:read_addr_from_reg use address_from_register. That caused a bunch of regressions, but it actually took me a long while to figure out what was going on. Turns out dwarf2-frame.c:read_addr_from_reg is called while computing the frame's CFA, from within dwarf2_frame_cache. address_from_register wants to create a register with frame_id set to the frame being constructed. To create the frame id, we again call dwarf2_frame_cache, which given: static struct dwarf2_frame_cache * dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) { ... if (*this_cache) return *this_cache; returns an incomplete object to the caller: static void dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache, struct frame_id *this_id) { struct dwarf2_frame_cache *cache = dwarf2_frame_cache (this_frame, this_cache); ... (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); } As cache->cfa is still 0 (we were trying to compute it!), and get_frame_id recalls this id from here on, we end up with a broken frame id in recorded for this frame. Later, when inspecting locals, the dwarf machinery needs to know the selected frame's base, which calls get_frame_base: CORE_ADDR get_frame_base (struct frame_info *fi) { return get_frame_id (fi).stack_addr; } which as seen above then returns 0 ... So I gave up using address_from_register. But, the pain of investigating this made me want to have GDB itself assert that recursion never happens here. So I wrote a patch to do that. But, it triggers on current mainline, because dwarf2_tailcall_sniffer_first, called from dwarf2_frame_cache, unwinds the this_frame. A sniffer shouldn't be trying to unwind, exactly because of this sort of tricky issue. The patch defers calling dwarf2_tailcall_sniffer_first until it's really necessary, in dwarf2_frame_prev_register (thus actually outside the sniffer path). As this makes the call to dwarf2_frame_sniffer in dwarf2_frame_cache unnecessary again, the patch removes that too. Tested on x86_64 Fedora 17. gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * dwarf2-frame.c (struct dwarf2_frame_cache) <checked_tailcall_bottom, entry_cfa_sp_offset, entry_cfa_sp_offset_p>: New fields. (dwarf2_frame_cache): Adjust to use the new cache fields instead of locals. Don't call dwarf2_tailcall_sniffer_first here. (dwarf2_frame_prev_register): Call it here, but only once.
2013-11-22Revert "Don't let two frames with the same id end up in the frame chain."Pedro Alves4-646/+17
This reverts commit be2c48b4d50b992ba83bc51f086e316621a03a14.
2013-11-22Revert "Make use of the frame stash to detect wider stack cycles."Pedro Alves1-88/+63
This reverts commit f5b0ed3c8ce42b0dd6b6caa0b3d7b7e734311afe.
2013-11-22Revert "Eliminate dwarf2_frame_cache recursion, don't unwind from the dwarf2 ↵Pedro Alves2-32/+15
sniffer (move dwarf2_tailcall_sniffer_first elsewhere)." This reverts commit 1dc8686c48e72fc02723d44ee0fecde0d233c74e.
2013-11-22Eliminate dwarf2_frame_cache recursion, don't unwind from the dwarf2 sniffer ↵Pedro Alves2-15/+32
(move dwarf2_tailcall_sniffer_first elsewhere). Two rationales, same patch. TL;DR 1: dwarf2_frame_cache recursion is evil. dwarf2_frame_cache calls dwarf2_tailcall_sniffer_first which then recurses into dwarf2_frame_cache. TL;DR 2: An unwinder trying to unwind is evil. dwarf2_frame_sniffer calls dwarf2_frame_cache which calls dwarf2_tailcall_sniffer_first which then tries to unwind the PC of the previous frame. Avoid all that by deferring dwarf2_tailcall_sniffer_first until it's really necessary. Rationale 1 =========== A frame sniffer should not try to unwind, because that bypasses all the validation checks done by get_prev_frame. The UNWIND_SAME_ID scenario is one such case where GDB is currently broken because (in part) of this (the next patch adds a test that would fail without this). GDB goes into an infinite loop in value_fetch_lazy, here: while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val)) { frame = frame_find_by_id (VALUE_FRAME_ID (new_val)); ... new_val = get_frame_register_value (frame, regnum); } (top-gdb) bt #0 value_fetch_lazy (val=0x11516d0) at ../../src/gdb/value.c:3510 #1 0x0000000000584bd8 in value_optimized_out (value=0x11516d0) at ../../src/gdb/value.c:1096 #2 0x00000000006fe7a1 in frame_register_unwind (frame=0x1492600, regnum=16, optimizedp=0x7fffffffcdec, unavailablep=0x7fffffffcde8, lvalp=0x7fffffffcdd8, addrp= 0x7fffffffcde0, realnump=0x7fffffffcddc, bufferp=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:940 #3 0x00000000006fea3a in frame_unwind_register (frame=0x1492600, regnum=16, buf=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:990 #4 0x0000000000473b9b in i386_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/i386-tdep.c:1771 #5 0x0000000000601dfa in gdbarch_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/gdbarch.c:2870 #6 0x0000000000693db5 in dwarf2_tailcall_sniffer_first (this_frame=0x1492600, tailcall_cachep=0x14926f0, entry_cfa_sp_offsetp=0x7fffffffcf00) at ../../src/gdb/dwarf2-frame-tailcall.c:389 #7 0x0000000000690928 in dwarf2_frame_cache (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1245 #8 0x0000000000690f46 in dwarf2_frame_sniffer (self=0x8e4980, this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1423 #9 0x000000000070203b in frame_unwind_find_by_frame (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/frame-unwind.c:112 #10 0x00000000006fd681 in get_frame_id (fi=0x1492600) at ../../src/gdb/frame.c:408 #11 0x00000000007006c2 in get_prev_frame_1 (this_frame=0xdc1860) at ../../src/gdb/frame.c:1826 #12 0x0000000000700b7a in get_prev_frame (this_frame=0xdc1860) at ../../src/gdb/frame.c:2056 #13 0x0000000000514588 in frame_info_to_frame_object (frame=0xdc1860) at ../../src/gdb/python/py-frame.c:322 #14 0x000000000051784c in bootstrap_python_frame_filters (frame=0xdc1860, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1396 #15 0x0000000000517a6f in apply_frame_filter (frame=0xdc1860, flags=7, args_type=CLI_SCALAR_VALUES, out=0xed7a90, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1492 #16 0x00000000005e77b0 in backtrace_command_1 (count_exp=0x0, show_locals=0, no_filters=0, from_tty=1) at ../../src/gdb/stack.c:1777 #17 0x00000000005e7c0f in backtrace_command (arg=0x0, from_tty=1) at ../../src/gdb/stack.c:1891 #18 0x00000000004e37a7 in do_cfunc (c=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:107 #19 0x00000000004e683c in cmd_func (cmd=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:1882 #20 0x00000000006f35ed in execute_command (p=0xcc66c2 "", from_tty=1) at ../../src/gdb/top.c:468 #21 0x00000000005f8853 in command_handler (command=0xcc66c0 "bt") at ../../src/gdb/event-top.c:435 #22 0x00000000005f8e12 in command_line_handler (rl=0xfe05f0 "@") at ../../src/gdb/event-top.c:632 #23 0x000000000074d2c6 in rl_callback_read_char () at ../../src/readline/callback.c:220 #24 0x00000000005f8375 in rl_callback_read_char_wrapper (client_data=0x0) at ../../src/gdb/event-top.c:164 #25 0x00000000005f876a in stdin_event_handler (error=0, client_data=0x0) at ../../src/gdb/event-top.c:375 #26 0x00000000005f72fa in handle_file_event (data=...) at ../../src/gdb/event-loop.c:768 #27 0x00000000005f67a3 in process_event () at ../../src/gdb/event-loop.c:342 #28 0x00000000005f686a in gdb_do_one_event () at ../../src/gdb/event-loop.c:406 #29 0x00000000005f68bb in start_event_loop () at ../../src/gdb/event-loop.c:431 #30 0x00000000005f83a7 in cli_command_loop (data=0x0) at ../../src/gdb/event-top.c:179 #31 0x00000000005eeed3 in current_interp_command_loop () at ../../src/gdb/interps.c:327 #32 0x00000000005ef8ff in captured_command_loop (data=0x0) at ../../src/gdb/main.c:267 #33 0x00000000005ed2f6 in catch_errors (func=0x5ef8e4 <captured_command_loop>, func_args=0x0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL) at ../../src/gdb/exceptions.c:524 #34 0x00000000005f0d21 in captured_main (data=0x7fffffffd9e0) at ../../src/gdb/main.c:1067 #35 0x00000000005ed2f6 in catch_errors (func=0x5efb9b <captured_main>, func_args=0x7fffffffd9e0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL) at ../../src/gdb/exceptions.c:524 #36 0x00000000005f0d57 in gdb_main (args=0x7fffffffd9e0) at ../../src/gdb/main.c:1076 #37 0x000000000045bb6a in main (argc=4, argv=0x7fffffffdae8) at ../../src/gdb/gdb.c:34 (top-gdb) GDB is trying to unwind the PC register of the previous frame (frame #5 above), starting from the frame being sniffed (the THIS frame). But the THIS frame's unwinder says the PC of the previous frame is actually the same as the previous's frame's next frame (which is the same frame we started with, the THIS frame), therefore it returns an lval_register lazy value with frame set to THIS frame. And so the value_fetch_lazy loop never ends. Rationale 2 =========== As an experiment, I tried making dwarf2-frame.c:read_addr_from_reg use address_from_register. That caused a bunch of regressions, but it actually took me a long while to figure out what was going on. Turns out dwarf2-frame.c:read_addr_from_reg is called while computing the frame's CFA, from within dwarf2_frame_cache. address_from_register wants to create a register with frame_id set to the frame being constructed. To create the frame id, we again call dwarf2_frame_cache, which given: static struct dwarf2_frame_cache * dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) { ... if (*this_cache) return *this_cache; returns an incomplete object to the caller: static void dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache, struct frame_id *this_id) { struct dwarf2_frame_cache *cache = dwarf2_frame_cache (this_frame, this_cache); ... (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); } As cache->cfa is still 0 (we were trying to compute it!), and get_frame_id recalls this id from here on, we end up with a broken frame id in recorded for this frame. Later, when inspecting locals, the dwarf machinery needs to know the selected frame's base, which calls get_frame_base: CORE_ADDR get_frame_base (struct frame_info *fi) { return get_frame_id (fi).stack_addr; } which as seen above then returns 0 ... So I gave up using address_from_register. But, the pain of investigating this made me want to have GDB itself assert that recursion never happens here. So I wrote a patch to do that. But, it triggers on current mainline, because dwarf2_tailcall_sniffer_first, called from dwarf2_frame_cache, unwinds the this_frame. A sniffer shouldn't be trying to unwind, exactly because of this sort of tricky issue. The patch defers calling dwarf2_tailcall_sniffer_first until it's really necessary, in dwarf2_frame_prev_register (thus actually outside the sniffer path). As this makes the call to dwarf2_frame_sniffer in dwarf2_frame_cache unnecessary again, the patch removes that too. Tested on x86_64 Fedora 17. gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * dwarf2-frame.c (struct dwarf2_frame_cache) <checked_tailcall_bottom, entry_cfa_sp_offset, entry_cfa_sp_offset_p>: New fields. (dwarf2_frame_cache): Adjust to use the new cache fields instead of locals. Don't call dwarf2_tailcall_sniffer_first here. (dwarf2_frame_prev_register): Call it here, but only once.
2013-11-22Make use of the frame stash to detect wider stack cycles.Pedro Alves1-63/+88
Tested on x86_64 Fedora 17. gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> Tom Tromey <tromey@redhat.com> * frame.c (frame_stash_add): Now returns whether a frame with the same ID was already known. (compute_frame_id): New function, factored out from get_frame_id. (get_frame_id): No longer lazilly compute the frame id here. (get_prev_frame_if_no_cycle): New function. Detects wider stack cycles. (get_prev_frame_1): Use it instead of get_prev_frame_raw directly, and checking for stack cycles here.
2013-11-22Don't let two frames with the same id end up in the frame chain.Pedro Alves4-17/+646
The UNWIND_SAME_ID check is done between THIS_FRAME and the next frame when we go try to unwind the previous frame. But at this point, it's already too late -- we ended up with two frames with the same ID in the frame chain. Each frame having its own ID is an invariant assumed throughout GDB. This patch applies the UNWIND_SAME_ID detection earlier, right after the previous frame is unwound, discarding the dup frame if a cycle is detected. The patch includes a new test that fails before the change. Before the patch, the test causes an infinite loop in GDB, after the patch, the UNWIND_SAME_ID logic kicks in and makes the backtrace stop with: Backtrace stopped: previous frame identical to this frame (corrupt stack?) The test uses dwarf CFI to emulate a corrupted stack with a cycle. It has a function with registers marked DW_CFA_same_value (most importantly RSP/RIP), so that GDB computes the same ID for that frame and its caller. IOW, something like this: #0 - frame_id_1 #1 - frame_id_2 #2 - frame_id_3 #3 - frame_id_4 #4 - frame_id_4 <<<< outermost (UNWIND_SAME_ID). (The test's code is just a copy of dw2-reg-undefined.S / dw2-reg-undefined.c, adjusted to use DW_CFA_same_value instead of DW_CFA_undefined, and to mark a different set of registers.) The infinite loop is here, in value_fetch_lazy: while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val)) { frame = frame_find_by_id (VALUE_FRAME_ID (new_val)); ... new_val = get_frame_register_value (frame, regnum); } get_frame_register_value can return a lazy register value pointing to the next frame. This means that the register wasn't clobbered by FRAME; the debugger should therefore retrieve its value from the next frame. To be clear, get_frame_register_value unwinds the value in question from the next frame: struct value * get_frame_register_value (struct frame_info *frame, int regnum) { return frame_unwind_register_value (frame->next, regnum); ^^^^^^^^^^^ } In other words, if we get a lazy lval_register, it should have the frame ID of the _next_ frame, never of FRAME. At this point in value_fetch_lazy, the whole relevant chunk of the stack up to frame #4 has already been unwound. The loop always "unlazies" lval_registers in the "next/innermost" direction, not in the "prev/unwind further/outermost" direction. So say we're looking at frame #4. get_frame_register_value in frame #4 can return a lazy register value of frame #3. So the next iteration, frame_find_by_id tries to read the register from frame #3. But, since frame #4 happens to have same id as frame #3, frame_find_by_id returns frame #4 instead. Rinse, repeat, and we have an infinite loop. This is an old latent problem, exposed by the recent addition of the frame stash. Before we had a stash, frame_find_by_id(frame_id_4) would walk over all frames starting at the current frame, and would always find #3 first. The stash happens to return #4 instead: struct frame_info * frame_find_by_id (struct frame_id id) { struct frame_info *frame, *prev_frame; ... /* Try using the frame stash first. Finding it there removes the need to perform the search by looping over all frames, which can be very CPU-intensive if the number of frames is very high (the loop is O(n) and get_prev_frame performs a series of checks that are relatively expensive). This optimization is particularly useful when this function is called from another function (such as value_fetch_lazy, case VALUE_LVAL (val) == lval_register) which already loops over all frames, making the overall behavior O(n^2). */ frame = frame_stash_find (id); if (frame) return frame; for (frame = get_current_frame (); ; frame = prev_frame) { gdb/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * frame.c (get_prev_frame_1): Do the UNWIND_SAME_ID check between this frame and the new previous frame, not between this frame and the next frame. gdb/testsuite/ 2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * gdb.dwarf2/dw2-dup-frame.S: New file. * gdb.dwarf2/dw2-dup-frame.c: New file. * gdb.dwarf2/dw2-dup-frame.exp: New file.
2013-11-22 * scripttempl/avr.sc: Set .data section's LMA to next availableSenthil Kumar Selvaraj2-2/+7
address in text region.
2013-11-21Move types_deeply_equal from py-type.c to gdbtypes.c.Doug Evans4-187/+229
* gdbtypes.c: #include bcache.h, dwarf2loc.h. (type_equality_entry): Move here from python/py-type.c. (type_equality_entry_d): Ditto. (compare_maybe_null_strings, check_types_equal): Ditto. (check_types_worklist, types_deeply_equal): Ditto. * gdbtypes.h (types_deeply_equal): Declare. * python/py-type.c: Remove inclusion of bcache.h, dwarf2loc.h. (typy_richcompare): Update.
2013-11-22Check has_more in mi_create_dynamic_varobjYao Qi3-9/+18
Hi, I find "has_more" is not checked when a dynamic varobj is created in proc mi_create_dynamic_varobj. This patch adds the check to "has_more". gdb/testsuite: 2013-11-22 Yao Qi <yao@codesourcery.com> * lib/mi-support.exp (mi_create_dynamic_varobj): Update comment and add one more argument "has_more". * gdb.python/py-mi.exp: Callers update.
2013-11-22Use mi_create_floating_varobjYao Qi2-2/+7
In gdb.python/py-mi.exp, two varobjs container and nscont are created when pretty-printing is still not enabled, so they are not dynamic varobj, IIUC. In this patch, we use mi_create_floating_varobj instead of mi_create_dynamic_varobj. gdb/testsuite: 2013-11-22 Yao Qi <yao@codesourcery.com> * gdb.python/py-mi.exp: Use mi_create_floating_varobj instead of mi_create_dynamic_varobj.
2013-11-22daily updateAlan Modra1-1/+1
2013-11-21ld/ChangeLog:Andrew Pinski7-3/+88
* Makefile.am (ALL_64_EMULATION_SOURCES): Add eaarch64linux32.c and eaarch64linux32b.c (eaarch64linux32.c): New target. (eaarch64linux32b.c): Likewise. * Makefile.in: Regenerate. * configure.tgt (aarch64_be-*-linux*): Add aarch64linux32 and aarch64linux32b to targ_extra_libpath. (aarch64-*-linux*): Likewise. * emulparams/aarch64elf32.sh (SEPARATE_GOTPLT): Change to 12 (3 words). * emulparams/aarch64linux32.sh: New file. * emulparams/aarch64linux32b.sh: New file.
2013-11-21ld/ChangeLog:Andrew Pinski2-2/+10
* configure.tgt (aarch64_be-*-linux*): Split out the linux targets into targ_extra_libpath. (aarch64-*-linux*): Likewise.
2013-11-21config/ * picflag.m4 (m68k-*-*): Use default PIC flag.schwab4-6/+8
gcc/ * configure: Regenerate. libada/ * configure: Regenerate. libgcc/ * configure: Regenerate. libiberty/ * configure: Regenerate. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@204854 138bc75d-0d04-0410-961f-82ee72b054a4
2013-11-21 PR ld/16192Nick Clifton2-3/+8
* pe-dll.c (pe_create_runtime_relocator_reference): Zero the newly allocated idata5 block.
2013-11-21 * gprof.c (inline_file_names): New variable.Conrad Hoffmann5-19/+46
(OPTION_INLINE_FILE_NAMES): Define. (long_options): Add --inline-file-names. (usage): Likewise. (main): Process --inline-file-names. * gprof.h: Add prototype for inline_file_names. * utils.c (print_name_only): Handle inline_file_names. * gprof.texi: Document new command line option.
2013-11-21Add bnd-branch-1 testusers/hjl/mpx/masterH.J. Lu4-0/+36
* ld-x86-64/mpx.exp: Run bnd-branch-1. * ld-x86-64/bnd-branch-1.d: New file. * ld-x86-64/bnd-branch-1.s: Likewise.
2013-11-21Fix version.dll binutils test on non native platformsTristan Gingold2-2/+6
2013-11-21 Tristan Gingold <gingold@adacore.com> * binutils-all/dlltool.exp: Add dlltool_gas_flag to version.dll test.
2013-11-21Doc 'dynamic' for command -var-list-childrenYao Qi2-0/+11
Hi, I find "dynamic=1" appear in the result of each child of the output of -var-list-children, -var-list-children ss1 ^done,numchild="2",children=[child={name="ss1.a",exp="a",numchild="0",type="struct s",thread-id="1",dynamic="1"},child={name="ss1.b",exp="b",numchild="0",type="struct s",thread-id="1",dynamic="1"}],has_more="0" but the doc doesn't mention this. This patch is to copy the description of "dynamic=1" here. gdb/doc: 2013-11-21 Yao Qi <yao@codesourcery.com> * gdb.texinfo (GDB/MI Variable Objects): Add attribute 'dynamic' for the output of command -var-list-children.
2013-11-21s/see @pxref/@pxref in docYao Qi2-1/+6
Looks "see" is unnecessary before @pxref. gdb/doc: 2013-11-21 Yao Qi <yao@codesourcery.com> * gdb.texinfo (Caching Target Data): Remove "see" before @pxref.
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