If we are going to write handler data (that is written as variable
length data following after the unwind info in .xdata), we need to
emit the handler data immediately, but for cases where no such
info is going to be written, skip emitting it right away. (Unwind
info for all remaining functions that hasn't gotten it emitted
directly is emitted at the end.)
This does slightly change the ordering of sections (triggering a
bunch of updates to DebugInfo/COFF tests), but the change should be
benign.
This also matches GCC's assembly output, which doesn't output
.seh_handlerdata unless it actually is needed.
For ARM64, the unwind info can be packed into the runtime function
entry itself (leaving no data in the .xdata section at all), but
that can only be done if there's no follow-on data in the .xdata
section. If emission of the unwind info is triggered via
EmitWinEHHandlerData (or the .seh_handlerdata directive), which
implicitly switches to the .xdata section, there's a chance of the
caller wanting to pass further data there, so the packed format
can't be used in that case.
Differential Revision: https://reviews.llvm.org/D87448
This changes the order of output sections and the output assembly, but
is otherwise NFC.
It simplifies the TLOF interface by removing two COFF-only methods.
Initial support for dwarf fission sections (-gsplit-dwarf) on wasm.
The most interesting change is support for writing 2 files (.o and .dwo) in the
wasm object writer. My approach moves object-writing logic into its own function
and calls it twice, swapping out the endian::Writer (W) in between calls.
It also splits the import-preparation step into its own function (and skips it when writing a dwo).
Differential Revision: https://reviews.llvm.org/D85685
An AsmPrinter should always be provided to the method because some forms
depend on its parameters. The only place in the codebase which passed
a nullptr value was found in the unit tests, so the patch updates it to
use some dummy AsmPrinter instead.
Differential Revision: https://reviews.llvm.org/D85293
In the case of LTO, several DWARF units can be emitted in one section.
For an extremely large application, they may exceed the limit of 4GiB
for 32-bit offsets. As it is now possible to emit 64-bit debugging info,
the patch enables storing the larger offsets.
Differential Revision: https://reviews.llvm.org/D87026
The string pool is shared among several units in the case of LTO,
and it potentially can exceed the limit of 4GiB for an extremely
large application. As it is now possible to emit 64-bit debugging
info, the limitation can be removed.
Differential Revision: https://reviews.llvm.org/D87025
The patch fixes emitting flags and the debug_line_offset field in
the header, as well as the reference to the macro string for
a pre-standard GNU .debug_macro extension.
Differential Revision: https://reviews.llvm.org/D87024
The patch fixes emitting the unit length field in the header of
the table and offsets to the entry pool. Note that while the patch
changes the common method to emit offsets, in fact, nothing is changed
for Apple accelerator tables, because we do not yet support DWARF64 for
those targets.
Differential Revision: https://reviews.llvm.org/D87023
The patch fixes emitting the header of the table. The content is
independent of the DWARF format.
Differential Revision: https://reviews.llvm.org/D87022
The transition is done by using methods of AsmPrinter which
automatically emit values in compliance with the selected DWARF format.
Differential Revision: https://reviews.llvm.org/D87013
The patch fixes calculating the size of the table and emitting
the fields which depend on the DWARF format by using methods that
choose appropriate sizes automatically.
Differential Revision: https://reviews.llvm.org/D87012
The patch fixes emitting the offset to the type DIE. All other fields
are already fixed in previous patches.
Differential Revision: https://reviews.llvm.org/D87021
These two fixes are better to go together because llvm-dwarfdump is
unable to dump a table when another one is malformed.
Differential Revision: https://reviews.llvm.org/D87018
The patch uses a common method to determine the appropriate form for
the value of the attribute.
Differential Revision: https://reviews.llvm.org/D87016
This is mostly an NFC patch because the involved methods are used when
emitting DWO files, which is incompatible with DWARFv3, or for platforms
where DWARF64 is not supported yet.
Differential Revision: https://reviews.llvm.org/D87015
The patch also adds a method to choose an appropriate DWARF form
to represent section offsets according to the version and the format
of producing debug info.
Differential Revision: https://reviews.llvm.org/D87014
The patch adds a switch to enable emitting debug info in the 64-bit
DWARF format. Most emitter for sections will be updated in the subsequent
patches, whereas for .debug_line and .debug_frame the emitters are in
the MC library, which is already updated.
For now, the switch is enabled only for 64-bit ELF targets.
Differential Revision: https://reviews.llvm.org/D87011
DW_FORM_sec_offset and DW_FORM_strp imply values of different sizes with
DWARF32 and DWARF64. The patch fixes DIE value classes to use correct
sizes when emitting their values. For DIELocList it ensures that the
requested DWARF form matches the current DWARF format because that class
uses a method that selects the size automatically.
Differential Revision: https://reviews.llvm.org/D87009
These methods are used to emit values which are 32-bit in DWARF32 and
64-bit in DWARF64. The patch fixes them so that they choose the length
automatically, depending on the DWARF format set in the Context.
Differential Revision: https://reviews.llvm.org/D87008
This patch introduces the new .bb_addr_map section feature which allows us to emit the bits needed for mapping binary profiles to basic blocks into a separate section.
The format of the emitted data is represented as follows. It includes a header for every function:
| Address of the function | -> 8 bytes (pointer size)
| Number of basic blocks in this function (>0) | -> ULEB128
The header is followed by a BB record for every basic block. These records are ordered in the same order as MachineBasicBlocks are placed in the function. Each BB Info is structured as follows:
| Offset of the basic block relative to function begin | -> ULEB128
| Binary size of the basic block | -> ULEB128
| BB metadata | -> ULEB128 [ MBB.isReturn() OR MBB.hasTailCall() << 1 OR MBB.isEHPad() << 2 ]
The new feature will replace the existing "BB labels" functionality with -basic-block-sections=labels.
The .bb_addr_map section scrubs the specially-encoded BB symbols from the binary and makes it friendly to profilers and debuggers.
Furthermore, the new feature reduces the binary size overhead from 70% bloat to only 12%.
For more information and results please refer to the RFC: https://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html
Reviewed By: MaskRay, snehasish
Differential Revision: https://reviews.llvm.org/D85408
Add a DBG_INSTR_REF instruction and a "debug instruction number" field to
MachineInstr. The two allow variable values to be specified by
identifying where the value is computed, rather than the register it lies
in, like so:
%0 = fooinst, debug-instr-number 1
[...]
DBG_INSTR_REF 1, 0
See the original RFC for motivation:
http://lists.llvm.org/pipermail/llvm-dev/2020-February/139440.html
This patch is NFCI; it only adds fields and other boiler plate.
Differential Revision: https://reviews.llvm.org/D85741
This is to fix CodeView build failure https://bugs.llvm.org/show_bug.cgi?id=47287
after DIsSubrange upgrade D80197
Assert condition is now removed and Count is calculated in case LowerBound
is absent or zero and Count or UpperBound is constant. If Count is unknown
it is later handled as VLA (currently Count is set to zero).
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D87406
a warning about clobbering reserved registers (NFC).
Also address some minor inefficiencies and style issues.
Differential Revision: https://reviews.llvm.org/D86088
As stated in section 6.1.1.2, DWARFv5, p. 142,
| The last entry for each name is followed by a zero byte that
| terminates the list. There may be gaps between the lists.
The patch changes emitting a 4-byte zero value to a 1-byte one, which
effectively removes the gap between entry lists, and thus saves
approximately 3 bytes per name; the calculation is not exact because
the total size of the table is aligned to 4.
Differential Revision: https://reviews.llvm.org/D86927
The member is not in use; the unit length for the table is emitted as
a difference between two labels. Moreover, the type of the member might
be misleading, because for DWARF64 the field should be 64 bit long.
Differential Revision: https://reviews.llvm.org/D86912
This reverts commit b9d977b0ca.
This cutoff is no longer required. The commit 34ffa7fc501 (D86153) introduces a
performance improvement which was tested against the motivating case for this
patch.
Discussed in differential revision: https://reviews.llvm.org/D86153
Almost NFC (see end).
The backwards scan in validThroughout significantly contributed to compile time
for a pathological case, causing the 'X86 Assembly Printer' pass to account for
roughly 70% of the run time. This patch guards the loop against running
unnecessarily, bringing the pass contribution down to 4%.
Almost NFC: There is a hack in validThroughout which promotes single constant
value DBG_VALUEs in the prologue to be live throughout the function. We're more
likely to hit this code path with this patch applied. Similarly to the parent
patches there is a small coverage change reported in the order of 10s of bytes.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D86153
With the changes introduced in D86151 we can now check for single locations
which span multiple blocks for inlined scopes and blocks.
D86151 introduced the InstructionOrdering parameter, replacing a scan through
MBB instructions. The functionality to compare instruction positions across
blocks was add there, and this patch just removes the exit checks that were
previously (but no longer) required.
CTMark shows a geomean binary size reduction of 2.2% for RelWithDebInfo builds.
llvm-locstats (using D85636) shows a very small variable location coverage
change in 5 of 10 binaries, but just like in D86151 it is only in the order of
10s of bytes.
Reviewed By: djtodoro
Differential Revision: https://reviews.llvm.org/D86152
With this patch we're now accounting for two more cases which should be
considered 'valid throughout': First, where RangeEnd is ScopeEnd. Second, where
RangeEnd comes before ScopeEnd when including meta instructions, but are both
preceded by the same non-meta instruction.
CTMark shows a geomean binary size reduction of 1.5% for RelWithDebInfo builds.
`llvm-locstats` (using D85636) shows a very small variable location coverage
change in 2 of 10 binaries, but it is in the order of 10s of bytes which lines
up with my expectations.
I've added a test which checks both of these new cases. The first check in the
test isn't strictly necessary for this patch. But I'm not sure that it is
explicitly tested anywhere else, and is useful for the final patch in the
series.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D86151
Group the map and methods used to query instruction ordering for trimVarLocs
(D82129) into a class. This will make it easier to reuse the functionality
upcoming patches.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D86150
This patch adds type information for SVE ACLE vector types,
by describing them as vectors, with a lower bound of 0, and
an upper bound described by a DWARF expression using the
AArch64 Vector Granule register (VG), which contains the
runtime multiple of 64bit granules in an SVE vector.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D86101
This patch adds support for representing Fortran `character(n)`.
Primarily patch is based out of D54114 with appropriate modifications.
Test case IR is generated using our downstream classic-flang. We're in process
of upstreaming flang PR's but classic-flang has dependencies on llvm, so
this has to get in first.
Patch includes functional test case for both IR and corresponding
dwarf, furthermore it has been manually tested as well using GDB.
Source snippet:
```
program assumedLength
call sub('Hello')
call sub('Goodbye')
contains
subroutine sub(string)
implicit none
character(len=*), intent(in) :: string
print *, string
end subroutine sub
end program assumedLength
```
GDB:
```
(gdb) ptype string
type = character (5)
(gdb) p string
$1 = 'Hello'
```
Reviewed By: aprantl, schweitz
Differential Revision: https://reviews.llvm.org/D86305
Fangrui Song