Summary:
llvm is missing support for DW_OP_implicit_value operation.
DW_OP_implicit_value op is indispensable for cases such as
optimized out long double variables.
For intro refer: DWARFv5 Spec Pg: 40 2.6.1.1.4 Implicit Location Descriptions
Consider the following example:
```
int main() {
long double ld = 3.14;
printf("dummy\n");
ld *= ld;
return 0;
}
```
when compiled with tunk `clang` as
`clang test.c -g -O1` produces following location description
of variable `ld`:
```
DW_AT_location (0x00000000:
[0x0000000000201691, 0x000000000020169b): DW_OP_constu 0xc8f5c28f5c28f800, DW_OP_stack_value, DW_OP_piece 0x8, DW_OP_constu 0x4000, DW_OP_stack_value, DW_OP_bit_piece 0x10 0x40, DW_OP_stack_value)
DW_AT_name ("ld")
```
Here one may notice that this representation is incorrect(DWARF4
stack could only hold integers(and only up to the size of address)).
Here the variable size itself is `128` bit.
GDB and LLDB confirms this:
```
(gdb) p ld
$1 = <invalid float value>
(lldb) frame variable ld
(long double) ld = <extracting data from value failed>
```
GCC represents/uses DW_OP_implicit_value in these sort of situations.
Based on the discussion with Jakub Jelinek regarding GCC's motivation
for using this, I concluded that DW_OP_implicit_value is most appropriate
in this case.
Link: https://gcc.gnu.org/pipermail/gcc/2020-July/233057.html
GDB seems happy after this patch:(LLDB doesn't have support
for DW_OP_implicit_value)
```
(gdb) p ld
p ld
$1 = 3.14000000000000012434
```
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D83560
This is an alternative proposal to D81476 (and D82084) - the details were sufficiently confusing to me it seemed easier to write some code and see how it looks.
Reviewers: SouraVX
Differential Revision: https://reviews.llvm.org/D84278
Summary:
This patch reduces file size in debug builds by dropping variable locations a
debugger user will not see.
After building the debug entity history map we loop through it. For each
variable we look at each entry. If the entry opens a location range which does
not intersect any of the variable's scope's ranges then we mark it for removal.
After visiting the entries for each variable we also mark any clobbering
entries which will no longer be referenced for removal, and then finally erase
the marked entries. This all requires the ability to query the order of
instructions, so before this runs we number them.
Tests:
Added llvm/test/DebugInfo/X86/trim-var-locs.mir
Modified llvm/test/DebugInfo/COFF/register-variables.ll
Branch folding merges the tails of if.then and if.else into if.else. Each
blocks' debug-locations point to different scopes so when they're merged we
can't use either. Because of this the variable 'c' ends up with a location
range which doesn't cover any instructions in its scope; with the patch
applied the location range is dropped and its flag changes to IsOptimizedOut.
Modified llvm/test/DebugInfo/X86/live-debug-variables.ll
Modified llvm/test/DebugInfo/ARM/PR26163.ll
In both tests an out of scope location is now removed. The remaining location
covers the entire scope of the variable allowing us to emit it as a single
location.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D82129
The test doesn't really demonstrate the use of the debug_loc.dwo section
distinct from the debug_loc section for strings in debug_macro.dwo -
because there are no strings that appear uin debug_loc.dwo that weren't
already in debug_loc, so the indexes would remain the same even if the
section that was used was fixed (to use debug_loc.dwo as per spec).
Summary:
This support is needed for the Fortran array variables with pointer/allocatable
attribute. This support enables debugger to identify the status of variable
whether that is currently allocated/associated.
for pointer array (before allocation/association)
without DW_AT_associated
(gdb) pt ptr
type = integer (140737345375288:140737354129776)
(gdb) p ptr
value requires 35017956 bytes, which is more than max-value-size
with DW_AT_associated
(gdb) pt ptr
type = integer (:)
(gdb) p ptr
$1 = <not associated>
for allocatable array (before allocation)
without DW_AT_allocated
(gdb) pt arr
type = integer (140737345375288:140737354129776)
(gdb) p arr
value requires 35017956 bytes, which is more than max-value-size
with DW_AT_allocated
(gdb) pt arr
type = integer, allocatable (:)
(gdb) p arr
$1 = <not allocated>
Testing
- unit test cases added
- check-llvm
- check-debuginfo
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D83544
DWARFListTableHeader::length() handles the zero value of HeaderData.Length
in a special way, which makes the result different from the calculated
value of FullLength, which leads to triggering an assertion. The patch
moves the assertion a bit later when `FullLength` is already checked for
minimal allowed value.
Differential Revision: https://reviews.llvm.org/D82886
Attach DbgLoc on insertvalue/extractvalue instructions created by
DeadArgumentElimination.
This fixes the PR46350.
Differential Revision: https://reviews.llvm.org/D81939
This patch uses ranges for debug information when a function contains basic block sections rather than using [lowpc, highpc]. This is also the first in a series of patches for debug info and does not contain the support for linker relaxation. That will be done as a follow up patch.
Differential Revision: https://reviews.llvm.org/D78851
When the zext gets promoted, it used to retain the original location,
which pessimizes the debugging experience causing an unexpected
jump in stepping at -Og.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46120 (which also
contains a full C repro).
Differential Revision: https://reviews.llvm.org/D81437
Record internal state based on register units. This is often more
efficient as there are typically fewer register units to update
compared to iterating over all the aliases of a register.
Original patch by Matthias Braun, but I've been rebasing and fixing it
for almost 2 years and fixed a few bugs causing intermediate failures
to make this patch independent of the changes in
https://reviews.llvm.org/D52010.
Summary:
This is a result of the discussion at D78113. Previously we would be
only giving the current offset at which the error was detected. However,
this was phrased somewhat ambiguously (as it could also mean that end of
data was at that offset). The new error message includes the current
offset as well as the extent of the data being read.
I've changed a couple of file-level static functions into private member
functions in order to avoid passing a bunch of new arguments everywhere.
Reviewers: dblaikie, jhenderson
Subscribers: hiraditya, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78558
For most tables, we already use commas in headers. This set of patches
unifies dumping the remaining ones.
Differential Revision: https://reviews.llvm.org/D80806
For most tables, we already use commas in headers. This set of patches
unifies dumping the remaining ones.
Differential Revision: https://reviews.llvm.org/D80806
For most tables, we already use commas in headers. This set of patches
unifies dumping the remaining ones.
Differential Revision: https://reviews.llvm.org/D80806
This patch adds support for emission of following DWARFv5 macro
forms in .debug_macro.dwo section:
- DW_MACRO_start_file
- DW_MACRO_end_file
- DW_MACRO_define_strx
- DW_MACRO_undef_strx
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D78866
Summary:
This caused incorrect debug information for parameters:
Previously, after a COPY of a parameter that changes the width,
we would emit a DBG_VALUE that continues to be associated to that
parameter, even though it now used a different width.
This made the LiveDebugValues pass assume the parameter value
got clobbered and it stopped tracking the parameter entry
value, leading to incorrect debug information.
Fixes https://bugs.llvm.org/show_bug.cgi?id=39715
Subscribers: aprantl, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D80819
DW_MACRO_define_strx forms are supported now in llvm-dwarfdump and these
forms can be used in both debug_macro[.dwo] sections. An added advantage
for using strx forms over strp forms is that it uses indices
approach instead of a relocation to debug_str section.
This patch unify the emission for debug_macro section.
Reviewed by: dblaikie, ikudrin
Differential Revision: https://reviews.llvm.org/D78865
This patch extends the parsing and dumping support of llvm-dwarfdump
for debug_macro.dwo section.
Following forms are supported:
- DW_MACRO_define
- DW_MACRO_undef
- DW_MACRO_start_file
- DW_MACRO_end_file
- DW_MACRO_define_strx
- DW_MACRO_undef_strx
- DW_MACRO_define_strp
- DW_MACRO_undef_strp
Reviewed by: ikudrin, dblaikie
Differential Revision: https://reviews.llvm.org/D78500
This patch upgrades DISubrange to support fortran requirements.
Summary:
Below are the updates/addition of fields.
lowerBound - Now accepts signed integer or DIVariable or DIExpression,
earlier it accepted only signed integer.
upperBound - This field is now added and accepts signed interger or
DIVariable or DIExpression.
stride - This field is now added and accepts signed interger or
DIVariable or DIExpression.
This is required to describe bounds of array which are known at runtime.
Testing:
unit test cases added (hand-written)
check clang
check llvm
check debug-info
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D80197
I've noticed an issue with "Data.getRelocatedValue(...)" call.
it might silently ignore an error when a content is truncated.
That leads to an infinite loop in the code (e.g. llvm-readobj hangs).
After fixing the issue I've found that actually we always tried
to read past the end of a section, even when a content was valid.
It happened because the terminator CIE (a CIE with the length == 0)
was never handled. At first I've tried just to stop adding the terminator
entry (and return), but it does not seem to be correct, because tools like
llvm-objdump might want to print something for such entries
(see comments in the code and test cases).
This patch fixes issues mentioned, provides new test cases for
both llvm-readobj and lib/DebugInfo and adds FIXMEs to existent
test cases related.
Differential revision: https://reviews.llvm.org/D80299
This adds a test to check that Length and CIE_id/CIE_pointer fields in
.debug_frame section are printed as 16-digit hex values if the records
are in the DWARF64 format.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of offsets in .debug_str_offsets sections so
that they are printed as 16-digit hex values if the contribution is in
the DWARF64 format.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of unit_length, debug_info_offset, and
debug_info_length fields in headers in .debug_pubname and
.debug_pubtypes sections so that they are printed as 16-digit hex values
if the contribution is in the DWARF64 format. Dumping of offsets in the
tables is changed in the same way.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of a unit_length field and offsets in headers
in .debug_loclists and .debug_rnglists sections so that they are printed
as 16-digit hex values if the contribution is in the DWARF64 format.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of unit_length and header_length fields in
headers in .debug_line sections so that they are printed as 16-digit hex
values if the contribution is in the DWARF64 format.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of the unit_length field in a unit header so
that it is printed as a 16-digit hex value if the unit is in the DWARF64
format.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of DWARF form values which sizes depend on
the DWARF format so that they are printed as 16-digit hex values for
DWARF64.
Differential Revision: https://reviews.llvm.org/D79997
The patch changes dumping of unit_length and debug_info_offset fields in
an address range header so that they are printed as 16-digit hex values
if the contribution is in the DWARF64 format.
Differential Revision: https://reviews.llvm.org/D79997
for variables in nested scopes (including inlined functions) if there is a
single location which covers the entire scope and the scope is contained in a
single block.
Based on work by @jmorse.
Reviewed By: vsk, aprantl
Differential Revision: https://reviews.llvm.org/D79571
Sourabh Singh Tomar