A typical dwarf assembly test-case start like this:
...
standard_testfile .c -debug.S
set asm_file [standard_output_file $srcfile2]
Dwarf::assemble $asm_file {
...
}
if { [prepare_for_testing "failed to prepare" ${testfile} \
[list $srcfile $asm_file] {nodebug}] } {
return -1
}
...
When accidentally using build_for_executable instead of
prepare_for_testing (or intentionally using it but forgetting to add
clean_restart $binfile or some such) the mistake may not be caught, because
another gdb instance is still running, and we may silently end up testing
compiler-generated DWARF.
This can be caused by something relatively obvious, like an earlier
prepare_for_testing or clean_restart, but also by something more obscure like
function_range, which may even be triggered by dwarf assembly like this:
...
{MACRO_AT_func {main}}
...
Fix this by calling gdb_exit at the end of function_range.
Also fix the fallout of that in test-case gdb.dwarf2/dw2-bad-elf.exp, where a
get_sizeof call used the gdb instance left lingering by function_range.
[ A better and more complete fix would add a new proc get_exec_info, that would
be called at the start of the dwarf assembly body:
...
Dwarf::assemble $asm_file {
get_exec_info {main foo} {int void*}
...
that would:
- do a prepare_for_testing with $srcfile (roughtly equivalent to what
MACRO_AT_func does,
- call function_range for all functions main and foo, without starting a
new gdb instance
- set corresponding variables at the call-site: main_start, main_len,
main_end, foo_start, foo_len, foo_end.
- get size for types int and void*
- set corresponding variables at the call-site: int_size, void_ptr_size.
- do a gdb_exit. ]
Tested on x86_64-linux.
It is currently not possible to use variables in locations lists. For
example, with:
diff --git a/gdb/testsuite/gdb.dwarf2/loclists-multiple-cus.exp b/gdb/testsuite/gdb.dwarf2/loclists-multiple-cus.exp
index 6b4f5c8cbb8..cdbf948619f 100644
--- a/gdb/testsuite/gdb.dwarf2/loclists-multiple-cus.exp
+++ b/gdb/testsuite/gdb.dwarf2/loclists-multiple-cus.exp
@@ -30,6 +30,8 @@ if {![dwarf2_support]} {
return 0
}
+set myconst 0x123456
+
# Test with 32-bit and 64-bit DWARF.
foreach_with_prefix is_64 {false true} {
if { $is_64 } {
@@ -49,6 +51,7 @@ foreach_with_prefix is_64 {false true} {
global func1_addr func1_len
global func2_addr func2_len
global is_64
+ global myconst
# The CU uses the DW_FORM_loclistx form to refer to the .debug_loclists
# section.
@@ -107,7 +110,7 @@ foreach_with_prefix is_64 {false true} {
list_ {
# When in func1.
start_length $func1_addr $func1_len {
- DW_OP_constu 0x123456
+ DW_OP_constu $myconst
DW_OP_stack_value
}
we get:
$ make check TESTS="*/loclists-multiple-cus.exp"
...
gdb compile failed, build/gdb/testsuite/outputs/gdb.dwarf2/loclists-multiple-cus/loclists-multiple-cus-dw32.S: Assembler messages:
build/gdb/testsuite/outputs/gdb.dwarf2/loclists-multiple-cus/loclists-multiple-cus-dw32.S:78: Error: leb128 operand is an undefined symbol: $myconst
...
That means $myconst was copied literally to the generated assembly
file.
This patch fixes it, by running subst on the location list body, in
the context of the caller. The fix is applied to both
Dwarf::loclists::table::list_::start_length and
Dwarf::loclists::table::list_::start_end.
Reported-by: Zoran Zaric <Zoran.Zaric@amd.com>
Change-Id: I615a64431857242d9f477d5699e3732df1b31322
The current syntax of proc arange is:
...
proc arange { arange_start arange_length {comment ""} {seg_sel ""} } {
...
and a typical call looks like:
...
arange $start $len
...
This style is somewhat annoying because if you want to specify the last
parameter, you need to give the default values of all the other optional ones
before as well:
...
arange $start $len "" $seg_sel
...
Update the syntax to:
...
proc arange { options arange_start arange_length } {
parse_options {
{ comment "" }
{ seg_sel "" }
}
...
such that a typical call looks like:
...
arange {} $start $len
...
and a call using seg_sel looks like:
...
arange {
seg_sel $seg_sel
} $start $len
...
Also update proc aranges, which already has an options argument, to use the
new proc parse_options.
Tested on x86_64-linux.
Co-Authored-By: Simon Marchi <simon.marchi@polymtl.ca>
A best practise for DWARF [1] is to generate .debug_aranges entries for CUs
even if they have no address range.
Generate .debug_arange entries for the dummy CUs added by the DWARF assembler.
Tested on x86_64-linux.
[1] http://wiki.dwarfstd.org/index.php?title=Best_Practices
Add a proc aranges such that we can generate .debug_aranges sections in dwarf
assembly using:
...
cu { label cu_label } {
...
}
aranges {} cu_label {
arange $addr $len [<comment>] [$segment_selector]
}
...
Tested on x86_64-linux.
We can use current dwarf assembly infrastructure to declare a label that marks
the start of the CU header:
...
declare_labels header_start_cu_a
_section ".debug_info"
header_start_cu_a : cu {} {
}
_section ".debug_info"
header_start_cu_b : cu {} {
}
...
on the condition that we switch to the .debug_info section before, which makes
this style of use fragile.
Another way to achieve the same is to use the label as generated by the cu
proc itself:
...
variable _cu_label
cu {} {
}
set header_start_cu_a $_cu_label
cu {} {
}
set header_start_cu_b $_cu_label
...
but again that seems fragile given that adding a new CU inbetween will
silently result in the wrong value for the label.
Add a label option to proc cu such that we can simply do:
...
cu { label header_start_cu_a } {
}
cu { label header_start_cu_b } {
}
...
Tested on x86_64-linux.
Say one compiles a hello.c:
...
$ gcc -g hello.c
...
On openSUSE Leap 15.2 and Tumbleweed, the CU for hello.c is typically not the
first in .debug_info, nor the last, due to presence of debug information in
objects for sources like:
- ../sysdeps/x86_64/start.S
- init.c
- ../sysdeps/x86_64/crti.S
- elf-init.c
- ../sysdeps/x86_64/crtn.S.
On other systems, say ubuntu 18.04.5, the CU for hello.c is typically the
first and the last in .debug_info.
This difference has caused me to find some errors in the dwarf assembly
using openSUSE, that didn't show up on other platforms.
Force the same situation on other platforms by adding a dummy start
and end CU.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2021-08-22 Tom de Vries <tdevries@suse.de>
PR testsuite/28235
* lib/dwarf.exp (Dwarf::dummy_cu): New proc.
(Dwarf::assemble): Add dummy start and end CU.
This patch addresses a design problem with the symbol_needs_eval_context
class. It exposes the problem by introducing two new testsuite test
cases.
To explain the issue, I first need to explain the dwarf_expr_context
class that the symbol_needs_eval_context class derives from.
The intention behind the dwarf_expr_context class is to commonize the
DWARF expression evaluation mechanism for different evaluation
contexts. Currently in gdb, the evaluation context can contain some or
all of the following information: architecture, object file, frame and
compilation unit.
Depending on the information needed to evaluate a given expression,
there are currently three distinct DWARF expression evaluators:
- Frame: designed to evaluate an expression in the context of a call
frame information (dwarf_expr_executor class). This evaluator doesn't
need a compilation unit information.
- Location description: designed to evaluate an expression in the
context of a source level information (dwarf_evaluate_loc_desc
class). This evaluator expects all information needed for the
evaluation of the given expression to be present.
- Symbol needs: designed to answer a question about the parts of the
context information required to evaluate a DWARF expression behind a
given symbol (symbol_needs_eval_context class). This evaluator
doesn't need a frame information.
The functional difference between the symbol needs evaluator and the
others is that this evaluator is not meant to interact with the actual
target. Instead, it is supposed to check which parts of the context
information are needed for the given DWARF expression to be evaluated by
the location description evaluator.
The idea is to take advantage of the existing dwarf_expr_context
evaluation mechanism and to fake all required interactions with the
actual target, by returning back dummy values. The evaluation result is
returned as one of three possible values, based on operations found in a
given expression:
- SYMBOL_NEEDS_NONE,
- SYMBOL_NEEDS_REGISTERS and
- SYMBOL_NEEDS_FRAME.
The problem here is that faking results of target interactions can yield
an incorrect evaluation result.
For example, if we have a conditional DWARF expression, where the
condition depends on a value read from an actual target, and the true
branch of the condition requires a frame information to be evaluated,
while the false branch doesn't, fake target reads could conclude that a
frame information is not needed, where in fact it is. This wrong
information would then cause the expression to be actually evaluated (by
the location description evaluator) with a missing frame information.
This would then crash the debugger.
The gdb.dwarf2/symbol_needs_eval_fail.exp test introduces this
scenario, with the following DWARF expression:
DW_OP_addr $some_variable
DW_OP_deref
# conditional jump to DW_OP_bregx
DW_OP_bra 4
DW_OP_lit0
# jump to DW_OP_stack_value
DW_OP_skip 3
DW_OP_bregx $dwarf_regnum 0
DW_OP_stack_value
This expression describes a case where some variable dictates the
location of another variable. Depending on a value of some_variable, the
variable whose location is described by this expression is either read
from a register or it is defined as a constant value 0. In both cases,
the value will be returned as an implicit location description on the
DWARF stack.
Currently, when the symbol needs evaluator fakes a memory read from the
address behind the some_variable variable, the constant value 0 is used
as the value of the variable A, and the check returns the
SYMBOL_NEEDS_NONE result.
This is clearly a wrong result and it causes the debugger to crash.
The scenario might sound strange to some people, but it comes from a
SIMD/SIMT architecture where $some_variable is an execution mask. In
any case, it is a valid DWARF expression, and GDB shouldn't crash while
evaluating it. Also, a similar example could be made based on a
condition of the frame base value, where if that value is concluded to
be 0, the variable location could be defaulted to a TLS based memory
address.
The gdb.dwarf2/symbol_needs_eval_timeout.exp test introduces a second
scenario. This scenario is a bit more abstract due to the DWARF
assembler lacking the CFI support, but it exposes a different
manifestation of the same problem. Like in the previous scenario, the
DWARF expression used in the test is valid:
DW_OP_lit1
DW_OP_addr $some_variable
DW_OP_deref
# jump to DW_OP_fbreg
DW_OP_skip 4
DW_OP_drop
DW_OP_fbreg 0
DW_OP_dup
DW_OP_lit0
DW_OP_eq
# conditional jump to DW_OP_drop
DW_OP_bra -9
DW_OP_stack_value
Similarly to the previous scenario, the location of a variable A is an
implicit location description with a constant value that depends on a
value held by a global variable. The difference from the previous case
is that DWARF expression contains a loop instead of just one branch. The
end condition of that loop depends on the expectation that a frame base
value is never zero. Currently, the act of faking the target reads will
cause the symbol needs evaluator to get stuck in an infinite loop.
Somebody could argue that we could change the fake reads to return
something else, but that would only hide the real problem.
The general impression seems to be that the desired design is to have
one class that deals with parsing of the DWARF expression, while there
are virtual methods that deal with specifics of some operations.
Using an evaluator mechanism here doesn't seem to be correct, because
the act of evaluation relies on accessing the data from the actual
target with the possibility of skipping the evaluation of some parts of
the expression.
To better explain the proposed solution for the issue, I first need to
explain a couple more details behind the current design:
There are multiple places in gdb that handle DWARF expression parsing
for different purposes. Some are in charge of converting the expression
to some other internal representation (decode_location_expression,
disassemble_dwarf_expression and dwarf2_compile_expr_to_ax), some are
analysing the expression for specific information
(compute_stack_depth_worker) and some are in charge of evaluating the
expression in a given context (dwarf_expr_context::execute_stack_op
and decode_locdesc).
The problem is that all those functions have a similar (large) switch
statement that handles each DWARF expression operation. The result of
this is a code duplication and harder maintenance.
As a step into the right direction to solve this problem (at least for
the purpose of a DWARF expression evaluation) the expression parsing was
commonized inside of an evaluator base class (dwarf_expr_context). This
makes sense for all derived classes, except for the symbol needs
evaluator (symbol_needs_eval_context) class.
As described previously the problem with this evaluator is that if the
evaluator is not allowed to access the actual target, it is not really
evaluating.
Instead, the desired function of a symbol needs evaluator seems to fall
more into expression analysis category. This means that a more natural
fit for this evaluator is to be a symbol needs analysis, similar to the
existing compute_stack_depth_worker analysis.
Another problem is that using a heavyweight mechanism of an evaluator
to do an expression analysis seems to be an unneeded overhead. It also
requires a more complicated design of the parent class to support fake
target reads.
The reality is that the whole symbol_needs_eval_context class can be
replaced with a lightweight recursive analysis function, that will give
more correct result without compromising the design of the
dwarf_expr_context class. The analysis treats the expression byte
stream as a DWARF operation graph, where each graph node can be
visited only once and each operation can decide if the frame context
is needed for their evaluation.
The downside of this approach is adding of one more similar switch
statement, but at least this way the new symbol needs analysis will be
a lightweight mechnism and it will provide a correct result for any
given DWARF expression.
A more desired long term design would be to have one class that deals
with parsing of the DWARF expression, while there would be a virtual
methods that deal with specifics of some DWARF operations. Then that
class would be used as a base for all DWARF expression parsing mentioned
at the beginning.
This however, requires a far bigger changes that are out of the scope
of this patch series.
The new analysis requires the DWARF location description for the
argc argument of the main function to change in the assembly file
gdb.python/amd64-py-framefilter-invalidarg.S. Originally, expression
ended with a 0 value byte, which was never reached by the symbol needs
evaluator, because it was detecting a stack underflow when evaluating
the operation before. The new approach does not simulate a DWARF
stack anymore, so the 0 value byte needs to be removed because it
makes the DWARF expression invalid.
gdb/ChangeLog:
* dwarf2/loc.c (class symbol_needs_eval_context): Remove.
(dwarf2_get_symbol_read_needs): New function.
(dwarf2_loc_desc_get_symbol_read_needs): Remove.
(locexpr_get_symbol_read_needs): Use
dwarf2_get_symbol_read_needs.
gdb/testsuite/ChangeLog:
* gdb.python/amd64-py-framefilter-invalidarg.S : Update argc
DWARF location expression.
* lib/dwarf.exp (_location): Handle DW_OP_fbreg.
* gdb.dwarf2/symbol_needs_eval.c: New file.
* gdb.dwarf2/symbol_needs_eval_fail.exp: New file.
* gdb.dwarf2/symbol_needs_eval_timeout.exp: New file.
Without that it is impossible to debug on riscv64.
gdb/
PR symtab/27999
* dwarf2/loc.c (decode_debug_loclists_addresses): Support
DW_LLE_start_end.
gdb/testsuite/
PR symtab/27999
* lib/dwarf.exp (start_end): New proc inside loclists.
* gdb.dwarf2/loclists-start-end.exp: New file.
* gdb.dwarf2/loclists-start-end.c: New file.
This commit fixes fission support in the Dwarf assembler. I added the
new test gdb.dwarf2/fission-absolute-dwo.exp which is a simple example
of using the fission support. I also rewrote the existing test
gdb.dwarf2/fission-multi-cu.exp to use the new functionality (instead
of using an x86-64 only assembler file).
To better support compiling the assembler files produced by the Dwarf
assembler I have added the new proc build_executable_and_dwo_files in
lib/dwarf.exp, this replaces build_executable_from_fission_assembler,
all the tests that used the old proc have been updated. Where the old
proc assumed a single .S source file which contained the entire test,
the new proc allows for multiple source files.
The Dwarf assembler already had some fission support, however, this
was not actually used in any tests, and when I tried using it there
were a few issues.
The biggest change is that we now generate DW_FORM_GNU_addr_index
instead of DW_FORM_addr for the low and high pc in
_handle_macro_at_range, support for the DW_FORM_GNU_addr_index is new
in this commit.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/fission-absolute-dwo.c: New file.
* gdb.dwarf2/fission-absolute-dwo.exp: New file.
* gdb.dwarf2/fission-base.exp: Use build_executable_and_dwo_files
instead of build_executable_from_fission_assembler.
* gdb.dwarf2/fission-loclists-pie.exp: Likewise.
* gdb.dwarf2/fission-loclists.exp: Likewise.
I had written a DWARF location expression like
DW_OP_const1u
DW_OP_stack_value
... and was surprised to see that the DW_OP_stack_value didn't appear
in the "readelf" output.
The problem here is that DW_OP_const1u requires an operand, but
neither the DWARF assembler nor gas diagnosed this problem.
This patch adds some checking to Dwarf::_location to try to avoid this
in the future. The checking is done via a helper proc that also
dissects the argument list and sets an array in the caller's frame.
gdb/testsuite/ChangeLog
2021-03-31 Tom Tromey <tromey@adacore.com>
* lib/dwarf.exp (Dwarf::_get_args): New proc.
(Dwarf::_location): Use it.
When handling DWARF attributes of the form DW_FORM_strp the strings
should be placed in the .debug_str section, not .debug_string as they
currently are by the DWARF assembler (in lib/dwarf.exp).
I've added a test. This is as much to test the DWARF generator as it
is to test GDB as GCC makes frequent use of DW_FORM_strp so we can be
pretty sure this part of GDB is already well tested.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-using-debug-str.c: New file.
* gdb.dwarf2/dw2-using-debug-str.exp: New file.
* lib/dwarf.exp (Dwarf::DW_FORM_strp): Create .debug_str section,
not .debug_string.
If DWARF contains a reference to a "dwz" file, but there is no
.gnu_debugaltlink section, then gdb will crash. This happens because
dwarf2_get_dwz_file will return NULL, but some callers do not expect
this.
This patch changes dwarf2_get_dwz_file so that callers can require a
dwz file. Then, it updates the callers that are attempting to process
references to the dwz file to require one.
This includes a new testcase. The dwarf.exp changes don't handle the
new forms exactly correctly -- they are only handled well enough to
let this test case complete.
gdb/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* dwarf2/read.h (dwarf2_get_dwz_file): Add 'require' parameter.
* dwarf2/read.c (dwarf2_get_dwz_file): Add 'require' parameter.
(get_abbrev_section_for_cu, read_attribute_value)
(get_debug_line_section): Update.
* dwarf2/macro.c (dwarf_decode_macro_bytes): Update.
gdb/testsuite/ChangeLog
2021-03-06 Tom Tromey <tom@tromey.com>
* lib/dwarf.exp (_handle_DW_FORM): Treat DW_FORM_GNU_ref_alt and
DW_FORM_GNU_strp_alt like DW_FORM_sec_offset.
* gdb.dwarf2/dwznolink.exp: New file.
It is possible for the tables in the .debug_{rng,loc}lists sections to
not have an array of offsets. In that case, the offset_entry_count
field of the header is 0. The forms DW_FORM_{rng,loc}listx (reference
by index) can't be used with that table. Instead, the
DW_FORM_sec_offset form, which references a {rng,loc}list by direct
offset in the section, must be used. From what I saw, this is what GCC
currently produces.
Add tests for this case. I didn't see any bug related to this, I just
think that it would be nice to have coverage for this. A new
`-with-offset-array` option is added to the `table` procs, used when
generating {rng,loc}lists, to decide whether to generate the offset
array.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (rnglists): Add -no-offset-array option to
table proc.
* gdb.dwarf2/rnglists-sec-offset.exp: Add test for
.debug_rnglists table without offset array.
* gdb.dwarf2/loclists-sec-offset.exp: Add test for
.debug_loclists table without offset array.
Change-Id: I8e34a7bf68c9682215ffbbf66600da5b7db91ef7
Add tests for the various issues fixed in the previous patches.
Add a new "loclists" procedure to the DWARF assembler, to allow
generating .debug_loclists sections.
gdb/testsuite/ChangeLog:
PR gdb/26813
* lib/dwarf.exp (_handle_DW_FORM): Handle DW_FORM_loclistx.
(loclists): New proc.
* gdb.dwarf2/loclists-multiple-cus.c: New.
* gdb.dwarf2/loclists-multiple-cus.exp: New.
* gdb.dwarf2/loclists-sec-offset.c: New.
* gdb.dwarf2/loclists-sec-offset.exp: New.
Change-Id: I209bcb2a9482762ae943e518998d1f7761f76928
The _location proc is used to assemble a location description. It needs
to know some contextual information:
- size of an address
- size of an offset (into another DWARF section)
- DWARF version
It currently get all this directly from global variables holding the
compilation unit information. This is fine because as of now, all
location descriptions are generated in the context of creating a
compilation unit. However, a subsequent patch will generate location
descriptions while generating a .debug_loclists section. _location
should therefore no longer rely on the current compilation unit's
properties.
Change it to accept these values as parameters instead of accessing the
values for the CU.
No functional changes intended.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (_location): Add parameters.
(_handle_DW_FORM): Adjust.
Change-Id: Ib94981979c83ffbebac838081d645ad71c221637
Add tests for the various issues fixed in the previous patches.
Add a new "rnglists" procedure to the DWARF assembler, to allow
generating .debug_rnglists sections. A trivial change is required to
support the DWARF 5 CU header layout.
gdb/testsuite/ChangeLog:
PR gdb/26813
* lib/dwarf.exp (_handle_DW_FORM): Handle DW_FORM_rnglistx.
(cu): Generate header for DWARF 5.
(rnglists): New proc.
* gdb.dwarf2/rnglists-multiple-cus.exp: New.
* gdb.dwarf2/rnglists-sec-offset.exp: New.
Change-Id: I5b297e59c370c60cf671dec19796a6c3b9a9f632
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
Replace the "SPECIAL_expr" comment with either "DW_FORM_block" or
"DW_FORM_exprloc" in the abbrev.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::_handle_attribute): Handle SPECIAL_expr
specially, set attr_form_comment to the actual FORM string used.
Since DWARF version 4 expressions are represented by DW_FORM_exprloc
instead of a block form. Support this in the testsuite Dwarf Assembler
by setting the SPECIAL_expr form once we know the CU version.
This doesn't change any testsuite results, it just makes the produced
DWARF valid. gdb also accepts expressions in block form for DWARF
version 4 and above, but this is technically incorrect.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::_read_constants): Don't set
_constants(SPECIAL_expr) here, but set it...
(Dwarf::cu): ...here based on _cu_version.
When using the single-element form of argument to declare_labels, the
generated label (in the assembly file) is of the format ".LlabelN",
where N is a number.
I propose making it use the name of the label by default. Calling:
declare_labels foo
will generate the ".LfooN" in the assembly file (again, where N is a
number). When debugging the output of the DWARF assembler, it makes it
easier to map labels to the source. Also, when defining the same label
twice by mistake in the Tcl code (like I d id), it's easier to track the
error from the message to the root cause:
-/home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.dwarf2/implptrpiece/implptrpiece-dw.S:62: Error: symbol `.Llabel5' is already defined
+/home/smarchi/build/binutils-gdb/gdb/testsuite/outputs/gdb.dwarf2/implptrpiece/implptrpiece-dw.S:62: Error: symbol `.Lvar_label5' is already defined
This doesn't change anything for the test cases, it just makes the
assembly output a bit nicer.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (declare_labels): Use name as text if text is
not provided.
Change-Id: I63856c1fa6390498fd5b9d66f471f817ff0a465c
When creating a .debug_ranges section using the testsuite's DWARF
assembler, it currently looks like this:
ranges {
sequence {
{base ...}
{range ...}
{range ...}
}
}
The sub-tree of sequence is manually traversed as a list of lists. I
think it would be nicer if `base` and `range` where procedure, just like
the other levels:
ranges {
sequence {
base ...
range ...
range ...
}
}
That makes the implementation more robust, and the usage a bit nicer
(less special characters). It also allows having comments in between
the range list entries:
ranges {
sequence {
base ...
range ...
# Hello world.
range ...
}
}
... which doesn't work with the current approach.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (ranges): Handle "base" and "range" as
proceduresu.
* gdb.dwarf/dw2-bad-elf.exp: Adjust.
* gdb.dwarf2/dw2-inline-many-frames.exp: Adjust.
* gdb.dwarf2/dw2-inline-stepping.exp: Adjust.
* gdb.dwarf2/dw2-ranges-base.exp: Adjust.
* gdb.dwarf2/dw2-ranges-func.exp: Adjust.
* gdb.dwarf2/dw2-ranges-overlap.exp: Adjust.
* gdb.dwarf2/dw2-ranges-psym.exp: Adjust.
* gdb.dwarf2/enqueued-cu-base-addr.exp: Adjust.
Change-Id: I0b2af480faff54d0fd4214e0cc8d042d9583a865
The abbreviations table for a single compilation unit has two types of
terminators:
- a ".byte 0" pair denoting the end of an attribute list
- a single ".byte 0" denoting the end of the table
However, at the end of the .debug_abbrev section in dw2-line-number-zero-dw.S,
we have four ".byte 0" entries:
...
.uleb128 0x12 /* DW_AT_high_pc */
.uleb128 0x01 /* DW_FORM_addr */
.byte 0x0 /* Terminator */
.byte 0x0 /* Terminator */
.byte 0x0 /* Terminator */
.byte 0x0 /* Terminator */
...
The first two are the attribute list terminator, the third is the end-of-table
terminator, and the last is superfluous/incorrect.
Fix this by emitting instead:
...
.uleb128 0x12 /* DW_AT_high_pc */
.uleb128 0x01 /* DW_FORM_addr */
.byte 0x0 /* DW_AT - Terminator */
.byte 0x0 /* DW_FORM - Terminator */
.byte 0x0 /* Abbrev end - Terminator */
...
where the last comment resembles the comment for other abbreviation codes:
...
.section .debug_abbrev
.Labbrev1_begin:
.uleb128 2 /* Abbrev start */
...
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-11-03 Tom de Vries <tdevries@suse.de>
* lib/dwarf.exp (Dwarf::_handle_DW_TAG): Improve attribute list
terminator comments.
(Dwarf::cu, Dwarf::tu): Remove superfluous abbreviation table
terminator.
The only possible form for a DW_AT_low_pc attribute is DW_FORM_addr.
When specifying in dwarf assembly a low_pc attribute without explicit form:
...
{low_pc {main_label - 4}}
...
the resulting attribute uses DW_FORM_string, which is misinterpreted by gdb
when reading it as:
...
cu->base_address = attr->as_address ();
...
Stop using DW_FORM_string as default form. Instead, use a default form based
on the attribute name, if possible and unambiguous. Otherwise, error out.
F.i.:
- for DW_AT_low_pc we use DW_FORM_addr.
- For DW_AT_high_pc, we don't specify a default form because it could be
either address or constant class.
- For DW_AT_name, we use DW_FORM_string. While we could encode with
DW_FORM_strp instead, DW_FORM_string is always ok.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-10-23 Tom de Vries <tdevries@suse.de>
* lib/dwarf.exp (Dwarf::_guess_form): Return "" by default instead of
DW_FORM_string.
(Dwarf::_default_form): New proc.
(Dwarf::_handle_DW_TAG): Use _default_form. Error out if no form was
guessed.
When reading an exec with a .debug_line section containing a vendor-specific
extended opcode, we get:
...
$ gdb -batch -iex "set complaints 10" dw2-vendor-extended-opcode
During symbol reading: mangled .debug_line section
...
and reading of the .debug_line section is abandoned.
The vendor-specific extended opcode should be ignored, as specified in the
DWARF standard (7.1 Vendor Extensibility). [ FWIW, vendor-specific
standard opcodes are already ignored. ]
Fix this by ignoring all vendor-specific extended opcodes.
Build and tested on x86_64-linux.
gdb/ChangeLog:
2020-08-03 Tom de Vries <tdevries@suse.de>
PR symtab/26333
* dwarf2/read.c (dwarf_decode_lines_1): Ignore
DW_LNE_lo_user/DW_LNE_hi_user range.
gdb/testsuite/ChangeLog:
2020-08-03 Tom de Vries <tdevries@suse.de>
PR symtab/26333
* lib/dwarf.exp (DW_LNE_user): New proc.
* gdb.dwarf2/dw2-vendor-extended-opcode.c: New test.
* gdb.dwarf2/dw2-vendor-extended-opcode.exp: New file.
The dwarf assembly procs MACRO_AT_func and MACRO_AT_range have a src
parameter, which is set to $srcdir/$subdir/$srcfile in every single call.
Drop the src parameter and hardcode usage of $srcdir/$subdir/$srcfile in the
procs.
Build and reg-tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-07-17 Tom de Vries <tdevries@suse.de>
* lib/dwarf.exp (Dwarf::MACRO_AT_func, Dwarf::MACRO_AT_range): Drop
src parameter.
* gdb.dlang/watch-loc.exp: Update MACRO_AT_{func,range} calls.
* gdb.dwarf2/bitfield-parent-optimized-out.exp: Same.
* gdb.dwarf2/dw2-ifort-parameter.exp: Same.
* gdb.dwarf2/dw2-opt-structptr.exp: Same.
* gdb.dwarf2/dwz.exp: Same.
* gdb.dwarf2/implptr-optimized-out.exp: Same.
* gdb.dwarf2/implref-array.exp: Same.
* gdb.dwarf2/implref-const.exp: Same.
* gdb.dwarf2/implref-global.exp: Same.
* gdb.dwarf2/implref-struct.exp: Same.
* gdb.dwarf2/info-locals-optimized-out.exp: Same.
* gdb.dwarf2/opaque-type-lookup.exp: Same.
* gdb.dwarf2/var-access.exp: Same.
* gdb.dwarf2/varval.exp: Same.
* gdb.trace/entry-values.exp: Same.
The file lib/dwarf.exp contains:
...
# Declare a global label. This is typically used to refer to
# labels defined in other files, for example a function defined in
# a .c file.
proc extern {args} {
foreach name $args {
_op .global $name
}
}
...
The assembler directive to refer to labels defined in other files is
not .global, but .extern, and that one is ignored by gas.
Since we require gas for all dwarf assembly test-cases, remove the proc and
all it's uses.
Tested on x86_64-linux.
gdb/testsuite/ChangeLog:
2020-07-17 Tom de Vries <tdevries@suse.de>
* lib/dwarf.exp (Dwarf::extern): Remove.
* gdb.compile/compile-ops.exp: Remove use of Dwarf::extern.
* gdb.dlang/circular.exp: Same.
* gdb.dwarf2/comp-unit-lang.exp: Same.
* gdb.dwarf2/dw2-ifort-parameter.exp: Same.
* gdb.dwarf2/dw2-symtab-includes.exp: Same.
* gdb.dwarf2/dwz.exp: Same.
* gdb.dwarf2/imported-unit-abstract-const-value.exp: Same.
* gdb.dwarf2/imported-unit-runto-main.exp: Same.
* gdb.dwarf2/imported-unit.exp: Same.
* gdb.dwarf2/opaque-type-lookup.exp: Same.
The comments modified in this patch claim that the addr_size parameters
can take the value 32 or 64 (suggesting the value is in bits). In fact,
the expected value is in bytes, either 4 or 8.
The actual value in the DWARF info is in bytes. And we can see that the
default values used (if addr_size == "default") are:
if {$_cu_addr_size == "default"} {
if {[is_64_target]} {
set _cu_addr_size 8
} else {
set _cu_addr_size 4
}
}
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::cu, Dwarf::tu, Dwarf::lines): Change valid
values in documentation for addr_size to 4 and 8.
Change-Id: I4a02dca2bb7992198864e545ef099f020f54ff2f
Every time I write a test making use of the DWARF assembler I end up
copying in the function get_func_info. Duplicating code is bad, so
lets put this function into lib/dwarf.exp and remove all of the
duplicates.
There should be no changes in the testsuite behaviour after this
commit.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-inline-many-frames.exp (get_func_info): Delete.
* gdb.dwarf2/dw2-inline-small-func.exp: Pass options to
get_func_info.
(get_func_info): Delete.
* gdb.dwarf2/dw2-is-stmt-2.exp (get_func_info): Delete.
* gdb.dwarf2/dw2-is-stmt.exp (get_func_info): Delete.
* lib/dwarf.exp (get_func_info): New function.
Extend the Dejagnu DWARF compiler to support DW_LNS_set_file opcode.
This will be used in a later commit. There should be no change in the
testsuite after this commit.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::lines::program::DW_LNS_set_file): New
function.
When using the Dejagnu DWARF compiler tests will often use the
function_range helper function to extract the extents of a function.
If the plan is to compiler the file with non-default compiler flags
then we must pass those same compiler flags through to the
function_range helper function.
This will be used in a later commit, there should be no change in the
testsuite behaviour after this commit.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (function_range): Allow compiler options to be
specified.
This commit adds the ability to set and toggle the DWARF line table
is-stmt flag.
A DWARF line table can now be created with the attribute
'default_is_stmt' like this:
lines {version 2 default_is_stmt 0} label {
...
}
If 'default_is_stmt' is not specified then the current default is 1,
which matches the existing behaviour.
Inside the DWARF line table program you can now make use of
{DW_LNS_negate_stmt} to toggle the is-stmt flag, for example this
meaningless program:
lines {version 2 default_is_stmt 0} label {
include_dir "some_directory"
file_name "some_filename" 1
program {
{DW_LNS_negate_stmt}
{DW_LNE_end_sequence}
}
}
This new functionality will be used in a later commit.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::lines) Add support for modifying the
is-stmt flag in the line table.
Change-Id: Ia3f61d523826382dd2333f65b9aae368ad29c4a5
Fixes a bug in the DWARF assembler that prevents multiple line tables
from being created in a test. We currently don't initialise a couple
of flags, as a result we will only ever generate one end of file list,
and one end of header, in the first line table. Any additional line
tables will be missing these parts, and will therefore be corrupt.
This fix will be required for a later commit. There should be no
change in the testsuite after this commit.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf::lines): Reset _line_saw_program and
_line_saw_file.
Change-Id: Id7123f217a036f26ee32d608db3064dd43164596
When running gdb.dwarf2/multidictionary.exp with target board cc-with-dwz and
current dwz, we run into a dwz abort:
...
gdb compile failed, gdb/contrib/cc-with-tweaks.sh: line 188: 11484 Aborted \
(core dumped) $DWZ "$output_file" > /dev/null 2>&1
UNTESTED: gdb.dwarf2/multidictionary.exp: multidictionary.exp
...
The dwz abort (PR dwz/24169) is caused by an invalid DW_FORM_ref_addr in the
multidictionary binary.
The multidictionary binary is build from multidictionary.S which is generated
using the dwarf assembler, and multidictionary.S contains dwarf for 3
compilation units.
In multidictionary0.o (generated from multidictionary.S), we find a concrete
formal parameter DIE:
...
<2><dc>: Abbrev Number: 4 (DW_TAG_formal_parameter)
<dd> DW_AT_abstract_origin: <0xa6>
...
referring to an abstract formal parameter DIE at 0xa6:
...
<2><a6>: Abbrev Number: 8 (DW_TAG_formal_parameter)
<a7> DW_AT_name : msg
<ab> DW_AT_type : <0x92>
...
but in the multidictionary binary the concrete formal parameter DIE is still
referring to 0xa6:
...
<2><1a3>: Abbrev Number: 4 (DW_TAG_formal_parameter)
<1a4> DW_AT_abstract_origin: <0xa6>
...
while the abstract formal parameter DIE has moved to 0x16d:
...
<2><16d>: Abbrev Number: 8 (DW_TAG_formal_parameter)
<16e> DW_AT_name : msg
<172> DW_AT_type : <0x159>
...
The concrete formal parameter DIE is specified in multidictionary.S like this:
...
.Llabel21:
.uleb128 4
.4byte .Llabel17 - .Lcu1_begin
...
The problem is that the .Lcu1_begin label is assumed to mark the start of the
.debug_info section in the executable, but in fact it marks the start of the
first compilation unit from multidictionary.S in the executable. Usually
these two entities are the same, but they are not when linked in object files
contain dwarf info and are placed in the .debug_info section before the
compilation units generated from multidictionary.S.
Fix this in the dwarf assembler by generating instead the label itself:
...
.Llabel21:
.uleb128 4
.4byte .Llabel17
...
resulting in a relocation in the object file:
...
Offset Info Type Sym. Value Sym. Name + Addend
0000000000dd 00040000000a R_X86_64_32 0000000000000000 .debug_info + a6
...
and resulting in the correct offset in the executable:
...
<2><1a3>: Abbrev Number: 4 (DW_TAG_formal_parameter)
<1a4> DW_AT_abstract_origin: <0x16d>
...
Tested on x86_64-linux with native and cc-with-dwz.
gdb/testsuite/ChangeLog:
2019-05-07 Tom de Vries <tdevries@suse.de>
PR testsuite/24159
* lib/dwarf.exp: Fix handling of DW_FORM_ref_addr.
Dwarf5 defines DW_FORM_strx1 and others, which are similar
to DW_FORM_strx but uses 1-4 bytes unsigned integers. This is
a small step towards supporting dwarf5 in gdb.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
Recently I fixed a bug that caused a DW_OP_implicit_pointer with non-zero
offset into a DW_OP_implicit_value to be handled incorrectly on big-endian
targets. GDB ignored the offset and copied the wrong bytes:
https://sourceware.org/ml/gdb-patches/2017-01/msg00251.html
But there is still a similar issue when a DW_OP_implicit_pointer points
into a DW_OP_stack_value instead; and again, the offset is ignored. There
is an important difference, though: While implicit values are treated like
blocks of data and anchored at the lowest-addressed byte, stack values
traditionally contain integer numbers and are anchored at the *least
significant* byte. Also, stack values do not come in varying sizes, but
are cut down appropriately when used. Thus, on big-endian targets the
scenario looks like this (higher addresses shown right):
|<- - - - - Stack value - - - - - - ->|
| |
|<- original object ->|
|
| offset ->|####|
^^^^
de-referenced
implicit pointer
(Note how the original object's size influences the position of the
de-referenced implicit pointer within the stack value. This is not the
case for little-endian targets, where the original object starts at offset
zero within the stack value.)
This patch implements the logic indicated in the above diagram and adds an
appropriate test case. A new function dwarf2_fetch_die_type_sect_off is
added; it is used for retrieving the original object's type, so its size
can be determined. That type is passed to dwarf2_evaluate_loc_desc_full
via a new parameter.
gdb/ChangeLog:
* dwarf2loc.c (indirect_synthetic_pointer): Get data type of
pointed-to DIE and pass it to dwarf2_evaluate_loc_desc_full.
(dwarf2_evaluate_loc_desc_full): New parameter subobj_type; rename
byte_offset to subobj_byte_offset. Fix the handling of
DWARF_VALUE_STACK on big-endian targets when coming via an
implicit pointer.
(dwarf2_evaluate_loc_desc): Adjust call to
dwarf2_evaluate_loc_desc_full.
* dwarf2loc.h (dwarf2_fetch_die_type_sect_off): New declaration.
* dwarf2read.c (dwarf2_fetch_die_type_sect_off): New function.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp: Add support for DW_OP_implicit_pointer.
* gdb.dwarf2/nonvar-access.exp: Add test for stack value location
and implicit pointer into such a location.
DWARF-5 has new form DW_FORM_data16. The problem is that GDB cannot pass
16-byte constant as a constant value as that would require GDB to use GCC
extension __int128.
Formerly such data was coded as DW_FORM_block* so GDB still decodes
DW_FORM_data16 like DW_FORM_block*.
gdb/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (skip_one_die, read_attribute_value)
(dwarf2_const_value_attr, dump_die_shallow)
(dwarf2_get_attr_constant_value, dwarf2_fetch_constant_bytes)
(skip_form_bytes, attr_form_is_constant): Handle DW_FORM_data16.
gdb/testsuite/ChangeLog
2017-02-20 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/formdata16.c: New file.
* gdb.dwarf2/formdata16.exp: New file.
* lib/dwarf.exp (Dwarf): Add DW_FORM_data16.
This patch adds a DW_OP_implicit_value in dwarf assembler, and uses
dwarf assembler in implptr-64bit.exp. Using dwarf assembler in
implptr-64bit.exp exposes some limitations in dwarf assembler,
- some variables are not evaluated in the caller's context, so we
can not pass variable to assembler, like this
Dwarf::assemble $asm_file {
cu {
version $dwarf_version
addr_size $addr_size
is_64 $is_64
} {
}
and
{DW_AT_type :$struct_label "DW_FORM_ref$ref_addr_size"}
this limitation is fixed by adding "uplevel" and "subst".
- dwarf assembler doesn't emit DW_FORM_ref_addr for label referencing.
this limitation is fixed by adding a new character "%",
{ type %$int_label }
this means we want to emit DW_FORM_ref_addr for label referencing.
- we can't set the form of label referencing offset in dwarf assembler.
Nowadays, dwarf assembler guesses the form of labels, which is
DW_FORM_ref4. However, in implptr-64bit.exp, both DW_FORM_ref4
and DW_FORM_ref8 is used (see REF_ADDR in implptr-64bit.S). This
patch adds the flexibility of setting the form of label reference.
Both of them below are valid,
{DW_AT_type :$struct_label}
{DW_AT_type :$struct_label DW_FORM_ref8}
the former form is the default DW_FORM_ref4.
I compared the .debug_info of objects without and with this patch
applied. There is no changes except abbrev numbers.
gdb/testsuite:
2017-01-25 Andreas Arnez <arnez@linux.vnet.ibm.com>
Yao Qi <yao.qi@linaro.org>
* gdb.dwarf2/implptr-64bit.exp: Use dwarf assembler.
* gdb.dwarf2/implptr-64bit.S: Remove.
* lib/dwarf.exp (Dwarf): Handle character "%". Evaluate some
variables in caller's context. Add DW_OP_implicit_value.
DW_OP_GNU_implicit_pointer refers to a DIE with an offset of different
sizes in different dwarf versions. In v2, the size is the pointer size,
while in v3 and above, it is the ref_addr size. This patch fixes
dwarf assembler to emit the correct size of offset. We've already fixed
this size issue in gdb,
https://sourceware.org/ml/gdb-patches/2011-09/msg00451.html
gdb/testsuite:
2017-01-25 Yao Qi <yao.qi@linaro.org>
* lib/dwarf.exp (Dwarf::_location): Handle
DW_OP_GNU_implicit_pointer with proper size.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
gdb/ChangeLog:
* dwarf2loc.c (dwarf2_find_location_expression): For DWO files still
add base_offset.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (build_executable_from_fission_assembler): Pass
$options when building executable.
* gdb.dwarf2/fission-loclists-pie.c: New file.
* gdb.dwarf2/fission-loclists-pie.exp: New file.
