Commit Graph

3135 Commits

Author SHA1 Message Date
Bryan Chan 3404add468 [EarlyCSE] Verify hash code in regression tests
As discussed in D86843, -earlycse-debug-hash should be used in more regression
tests to catch inconsistency between the hashing and the equivalence check.

Differential Revision: https://reviews.llvm.org/D86863
2020-09-04 10:40:35 -04:00
Amy Huang 5fe33f7399 [DebugInfo] Make DWARF ignore sizes on forward declared class types.
Make sure the sizes for forward declared classes aren't emitted in
DWARF.

This comes before https://reviews.llvm.org/D87062, which adds sizes to
all classes with definitions.

Bug: https://bugs.llvm.org/show_bug.cgi?id=47338

Differential Revision: https://reviews.llvm.org/D87070
2020-09-03 11:01:49 -07:00
Igor Kudrin 3445ec9ba7 [DebugInfo] Emit a 1-byte value as a terminator of entries list in the name index.
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
2020-09-02 16:12:39 +07:00
OCHyams b6cca0ec05 Revert "[DWARF] Add cuttoff guarding quadratic validThroughout behaviour"
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
2020-08-27 11:52:30 +01:00
OCHyams 57d8acac64 [DwarfDebug] Improve validThroughout performance (4/4)
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
2020-08-27 11:52:30 +01:00
OCHyams 3c491881d2 [DwarfDebug] Improve multi-BB single location detection in validThroughout (3/4)
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
2020-08-27 11:52:29 +01:00
OCHyams 0b5a8050ea [DwarfDebug] Improve single location detection in validThroughout (2/4)
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
2020-08-27 11:52:29 +01:00
Sander de Smalen 4e9b66de3f [AArch64][SVE] Add missing debug info for ACLE types.
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
2020-08-27 10:56:42 +01:00
Sam Parker a3e41d4581 [ARM] Make MachineVerifier more strict about terminators
Fix the ARM backend's analyzeBranch so it doesn't ignore predicated
return instructions, and make the MachineVerifier rule more strict.

Differential Revision: https://reviews.llvm.org/D40061
2020-08-27 07:10:20 +01:00
Craig Topper 92d3e70df3 [X86] Change pentium4 tuning settings and scheduler model back to their values before D83913.
Clang now defaults to -march=pentium4 -mtune=generic so we don't
need modern tune settings on pentium4.
2020-08-26 15:38:12 -07:00
Jeremy Morse 5b9c2b1bea Revert "[LiveDebugValues][NFC] Add instr-ref tests, adapt old tests"
Asan has picked up a memory leak, which will require some investigation:

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/45372/steps/check-llvm%20asan/logs/stdio

This reverts commit 60db26a66d.
2020-08-26 17:19:13 +01:00
Jeremy Morse 60db26a66d [LiveDebugValues][NFC] Add instr-ref tests, adapt old tests
This patch adds a few tests in DebugInfo/MIR/InstrRef/ of interesting
behaviour that the instruction referencing implementation of
LiveDebugValues has. Mostly, these tests exist to ensure that if you
give the "-experimental-debug-variable-locations" command line switch,
the right implementation runs; and to ensure it behaves the same way as
the VarLoc LiveDebugValues implementation.

I've also touched roughly 30 other tests, purely to make the tests less
rigid about what output to accept. DBG_VALUE instructions are usually
printed with a trailing !debug-location indicating its scope:

  !debug-location !1234

However InstrRefBasedLDV produces new DebugLoc instances on the fly,
meaning there sometimes isn't a numbered node when they're printed,
making the output:

  !debug-location !DILocation(line: 0, blah blah)

Which causes a ton of these tests to fail. This patch removes checks for
that final part of each DBG_VALUE instruction. None of them appear to
be actually checking the scope is correct, just that it's present, so
I don't believe there's any loss in coverage here.

Differential Revision: https://reviews.llvm.org/D83054
2020-08-26 16:33:43 +01:00
Fangrui Song ba93844d11 [DebugInfo][test] Fix dwarf-callsite-related-attrs.ll after llvm-dwarfdump --statistics change 2020-08-22 14:09:19 -07:00
Fangrui Song 7646a67104 [DebugInfo][test] Move distringtype.ll to X86/ subdir to fix failures when X86 target is not built 2020-08-21 23:14:36 -07:00
Sourabh Singh Tomar 12edd4b364 Fix arm bot failure after f91d18eaa9
llc doesn't seem to automatically pick default `--triple`.
using `%llc_dwarf` should fix this.

Builder:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-quick/builds/20310

Error log:
bin/llc: error: : error: unable to get target for 'x86_64-unknown-linux-gnu', see --version and --triple.
2020-08-22 11:06:10 +05:30
Sourabh Singh Tomar f91d18eaa9 [DebugInfo][flang]Added support for representing Fortran assumed length strings
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
2020-08-22 10:13:40 +05:30
Sourabh Singh Tomar ef8992b9f0 Re-apply "[DebugInfo] Emit DW_OP_implicit_value for Floating point constants"
This patch was reverted in 7c182663a8 due to some failures
observed on PCC based machines. Failures were due to Endianness issue and
long double representation issues.

Patch is revised to address Endianness issue. Furthermore, support
for emission of `DW_OP_implicit_value` for `long double` has been removed
(since it was unclean at the moment). Planning to handle this in
a clean way soon!

For more context, please refer to following review link.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D83560
2020-08-20 01:39:42 +05:30
Sourabh Singh Tomar 9937872c02 Revert "[DebugInfo] Emit DW_OP_implicit_value for Floating point constants"
This reverts commit 15801f1619.
arc's land messed up! It removed the new commit message and took it
from revision.
2020-08-20 01:28:03 +05:30
Sourabh Singh Tomar 15801f1619 [DebugInfo] Emit DW_OP_implicit_value for Floating point constants
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
2020-08-20 01:20:40 +05:30
David Blaikie 1870b52f0c Recommit "PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units"
Originally committed as be3ef93bf5.
Reverted by b4bffdbadf due to bot
failures:
http://green.lab.llvm.org/green/job/clang-stage1-cmake-RA-expensive/17380/testReport/junit/LLVM/DebugInfo_X86/addr_tu_to_non_tu_ll/
http://45.33.8.238/win/22216/step_11.txt

MacOS failure due to testing Split DWARF which isn't compatible with
MachO.
Windows failure due to testing type units which aren't enabled on
Windows.

Fix both of these by applying an explicit x86 linux triple to the test.
2020-08-18 13:43:28 -07:00
Nico Weber b4bffdbadf Revert "PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units"
This reverts commit be3ef93bf5.
Test fails on macOS and Windows, e.g. http://45.33.8.238/win/22216/step_11.txt
2020-08-18 08:40:36 -04:00
David Blaikie be3ef93bf5 PR44685: DebugInfo: Handle address-use-invalid type units referencing non-type units
Theory was that we should never reach a non-type unit (eg: type in an
anonymous namespace) when we're already in the invalid "encountered an
address-use, so stop emitting types for now, until we throw out the
whole type tree to restart emitting in non-type unit" state. But that's
not the case (prior commit cleaned up one reason this wasn't exposed
sooner - but also makes it easier to test/demonstrate this issue)
2020-08-17 21:42:00 -07:00
David Blaikie 24c3dabef4 DebugInfo: Emit class template parameters first, before members
This reads more like what you'd expect the DWARF to look like (from the
lexical order of C++ - template parameters come before members, etc),
and also happens to make it easier to tickle (& thus test) a bug related
to type units and Split DWARF I'm about to fix.
2020-08-17 21:42:00 -07:00
Alexandre Ganea 98e01f56b0 Revert "Re-Re-land: [CodeView] Add full repro to LF_BUILDINFO record"
This reverts commit a3036b3863.

As requested in: https://reviews.llvm.org/D80833#2221866
Bug report: https://crbug.com/1117026
2020-08-17 15:49:18 -04:00
Dávid Bolvanský 0f14b2e6cb Revert "[BPI] Improve static heuristics for integer comparisons"
This reverts commit 50c743fa71. Patch will be split to smaller ones.
2020-08-17 20:44:33 +02:00
Igor Kudrin 95fad44e34 [DebugInfo] Avoid an infinite loop with a truncated pre-v5 .debug_str_offsets.dwo.
dumpStringOffsetsSection() expects the size of a contribution to be
correctly aligned. The patch adds the corresponding verifications for
pre-v5 cases.

Differential Revision: https://reviews.llvm.org/D85739
2020-08-14 13:11:37 +07:00
Dávid Bolvanský 50c743fa71 [BPI] Improve static heuristics for integer comparisons
Similarly as for pointers, even for integers a == b is usually false.

GCC also uses this heuristic.

Reviewed By: ebrevnov

Differential Revision: https://reviews.llvm.org/D85781
2020-08-13 19:54:27 +02:00
Dávid Bolvanský f9264995a6 Revert "[BPI] Improve static heuristics for integer comparisons"
This reverts commit 44587e2f7e. Sanitizer tests need to be updated.
2020-08-13 14:37:40 +02:00
Dávid Bolvanský 44587e2f7e [BPI] Improve static heuristics for integer comparisons
Similarly as for pointers, even for integers a == b is usually false.

GCC also uses this heuristic.

Reviewed By: ebrevnov

Differential Revision: https://reviews.llvm.org/D85781
2020-08-13 14:23:58 +02:00
Rainer Orth 7af4bbb643 [test] XFAIL two tests with inlining debug info issues on Sparc
Currently only two test failures remain on Sparc, both
`sparcv9-sun-solaris2.11` and `sparc64-unknown-linux-gnu`:

  LLVM :: DebugInfo/Generic/debug-label-inline.ll
  LLVM :: Linker/subprogram-linkonce-weak.ll

They seem related in that debug info isn't generated for instruction
bundles (like `retl+add` in the delay slot).

I've filed separate bugs for both files (Bug 47129 and 47131), though it's
probably the same issue.

This patch `XFAIL`s the tests.

Tested on `sparcv9-sun-solaris2.11` and `amd64-pc-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D85827
2020-08-13 11:12:52 +02:00
Vedant Kumar 30c1633386 Revert "[Instruction] Add updateLocationAfterHoist helper"
This reverts commit 4a646ca9e2.

This is causing some bots to fail with "!dbg attachment points at wrong
subprogram for function", like:

http://lab.llvm.org:8011/builders/sanitizer-windows/builds/67958/steps/stage%201%20check/logs/stdio
2020-08-11 14:54:09 -07:00
Amy Huang 54b6cca0f2 [globalopt] Change so that emitting fragments doesn't use the type size of DIVariables
When turning on -debug-info-kind=constructor we ran into a "fragment covers
entire variable" error during thinlto. The fragment is currently always
emitted if there is no type size, but sometimes the variable has a
forward declared struct type which doesn't have a size.

This changes the code to get the type size from the GlobalVariable instead.

Differential Revision: https://reviews.llvm.org/D85572
2020-08-11 14:50:56 -07:00
Vedant Kumar 4a646ca9e2 [Instruction] Add updateLocationAfterHoist helper
Introduce a helper on Instruction which can be used to update the debug
location after hoisting.

Use this in GVN and LICM, where we were mistakenly introducing new line
0 locations after hoisting (the docs recommend dropping the location in
this case).

For more context, see the discussion in https://reviews.llvm.org/D60913.

Differential Revision: https://reviews.llvm.org/D85670
2020-08-11 14:05:20 -07:00
David Stenberg e2f3240472 [DebugInfo] Allow GNU macro extension to be emitted
Allow the GNU .debug_macro extension to be emitted for DWARF versions
earlier than 5. The extension is basically what became DWARF 5's format,
except that a DW_AT_GNU_macros attribute is emitted, and some entries
like the strx entries are missing. In this patch I emit GNU's indirect
entries, which are the same as DWARF 5's strp entries.

This patch adds the extension behind a hidden LLVM flag,
-use-gnu-debug-macro. I would later want to enable it by default when
tuning for GDB and targeting DWARF versions earlier than 5.

The size of a Clang 8.0 binary built with RelWithDebInfo and the flags
"-gdwarf-4 -fdebug-macro" reduces from 1533 MB to 1349 MB with
.debug_macro (compared to 1296 MB without -fdebug-macro).

Reviewed By: SouraVX, dblaikie

Differential Revision: https://reviews.llvm.org/D82975
2020-08-11 17:00:25 +02:00
David Stenberg 91bd9db2cd [DebugInfo] Allow GNU macro extension to be read
Allow the GNU .debug_macro extension to be parsed and printed by
llvm-dwarfdump. In an upcoming patch support will be added for emitting
that format also.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D82974
2020-08-11 13:30:52 +02:00
Alexandre Ganea a3036b3863 Re-Re-land: [CodeView] Add full repro to LF_BUILDINFO record
This patch adds the missing information to the LF_BUILDINFO record, which allows for rebuilding a .CPP without any external dependency but the .OBJ itself (other than the compiler).

Some external tools that we are using (Recode, Live++) are extracting the information to reproduce a build without any knowledge of the build system. The LF_BUILDINFO stores a full path to the compiler, the PWD (CWD at program startup), a relative or absolute path to the TU, and the full CC1 command line. The command line needs to be freestanding (not depend on any environment variables). In the same way, MSVC doesn't store the provided command-line, but an expanded version (somehow their equivalent of CC1) which is also freestanding.

For more information see PR36198 and D43002.

Differential Revision: https://reviews.llvm.org/D80833
2020-08-10 13:36:30 -04:00
Rainer Orth 0b90a08f77 [test][DebugInfo] Adapt two tests for Sun assembler syntax on Sparc
Two DebugInfo tests currently `FAIL` on Sparc:

  LLVM :: DebugInfo/Generic/2010-06-29-InlinedFnLocalVar.ll
  LLVM :: DebugInfo/Generic/array.ll

both in a similar way.  E.g.

  : 'RUN: at line 1';   /var/llvm/local-sparcv9-A/bin/llc -O2 /vol/llvm/src/llvm-project/local/llvm/test/DebugInfo/Generic/2010-06-29-InlinedFnLocalVar.ll -o - | /var/llvm/local-sparcv9-A/bin/FileCheck /vol/llvm/src/llvm-project/local/llvm/test/DebugInfo/Generic/2010-06-29-InlinedFnLocalVar.ll

  /vol/llvm/src/llvm-project/local/llvm/test/DebugInfo/Generic/2010-06-29-InlinedFnLocalVar.ll:4:10: error: CHECK: expected string not found in input
  ; CHECK: debug_info,
           ^

On `amd64-pc-solaris2.11`, the corresponding line is

  .section        .debug_info,"",@progbits

while on `sparcv9-sun-solaris2.11` we have only

  .section        .debug_info

This happens because Sparc currently emits `.section` directives using the
style of the Solaris/SPARC assembler (controlled by `SunStyleELFSectionSwitchSyntax`).

This patch takes the easy way out and allows both forms while tightening the
check to only match the `.section` directive.

Tested on `sparcv9-sun-solaris2.11`, `amd64-pc-solaris2.11`,
`x86_64-pc-linux-gnu`, and `x86_64-apple-darwin20.0.0`.

Differential Revision: https://reviews.llvm.org/D85414
2020-08-08 09:13:47 +02:00
Rahman Lavaee 20a568c29d [Propeller]: Use a descriptive temporary symbol name for the end of the basic block.
This patch changes the functionality of AsmPrinter to name the basic block end labels as LBB_END${i}_${j}, with ${i} being the identifier for the function and ${j} being the identifier for the basic block. The new naming scheme is consistent with how basic block labels are named (.LBB${i}_{j}), and how function end symbol are named (.Lfunc_end${i}) and helps to write stronger tests for the upcoming patch for BB-Info section (as proposed in https://lists.llvm.org/pipermail/llvm-dev/2020-July/143512.html). The end label is used with basicblock-labels (BB-Info section in future) and basicblock-sections to compute the size of basic blocks and basic block sections, respectively. For BB sections, the section containing the entry basic block will not have a BB end label since it already gets the function end-label.
This label is cached for every basic block (CachedEndMCSymbol) like the label for the basic block (CachedMCSymbol).

Differential Revision: https://reviews.llvm.org/D83885
2020-08-05 13:17:19 -07:00
Fangrui Song 593e196297 [llvm-symbolizer] Switch command line parsing from llvm::cl to OptTable
for the advantage outlined by D83639 ([OptTable] Support grouped short options)

Some behavior changes:

* -i={0,false} is removed. Use --no-inlines instead.
* --demangle={0,false} is removed. Use --no-demangle instead
* -untag-addresses={0,false} is removed. Use --no-untag-addresses instead

Added a higher level API OptTable::parseArgs which handles optional
initial options populated from an environment variable, expands response
files recursively, and parses options.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D83530
2020-08-04 08:53:15 -07:00
Sriraman Tallam ca6b6d40ff Rename basic block sections options to be consistent.
D68049 created options for basic block sections: -fbasic-block-sections=,
-funique-basic-block-section-names. Rename options in llc and lld (--lto-)
to be consistent. Specifically,

+ Rename basicblock-sections to basic-block-sections
+ Rename unique-bb-section-names to unique-basic-block-section-names

Differential Revision: https://reviews.llvm.org/D84462
2020-07-31 11:50:55 -07:00
Arthur Eubanks 2ca6c422d2 [FunctionAttrs] Rename functionattrs -> function-attrs
To match NewPM pass name, and also for readability.
Also rename rpo-functionattrs -> rpo-function-attrs while we're here.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D84694
2020-07-28 09:09:13 -07:00
Amy Kwan 7c182663a8 Revert "Re-apply:" Emit DW_OP_implicit_value for Floating point constants""
This patch reverts commit `59a76d957a26` as it has caused failure on the
big endian PowerPC buildbots (as well as the SystemZ buildbots).
2020-07-27 09:44:13 -05:00
Djordje Todorovic 6371a0a00e [DWARF][EntryValues] Emit GNU extensions in the case of DWARF 4 + SCE
Emit DWARF 5 call-site symbols even though DWARF 4 is set,
only in the case of LLDB tuning.

This patch addresses PR46643.

Differential Revision: https://reviews.llvm.org/D83463
2020-07-24 14:33:57 +02:00
Djordje Todorovic cbb3571b0d [DWARF] Avoid entry_values production for SCE
SONY debugger does not prefer debug entry values feature, so
the plan is to avoid production of the entry values
by default when the tuning is SCE debugger.

The feature still can be enabled with the -debug-entry-values
option for the testing/development purposes.

This patch addresses PR46643.

Differential Revision: https://reviews.llvm.org/D83462
2020-07-24 13:34:05 +02:00
Sourabh Singh Tomar 59a76d957a Re-apply:" Emit DW_OP_implicit_value for Floating point constants"
This patch was reverted in 9d2da6759b due to assertion failure seen
in `test/DebugInfo/Sparc/subreg.ll`. Assertion failure was happening
due to malformed/unhandeled DwarfExpression.

Differential Revision: https://reviews.llvm.org/D83560
2020-07-23 13:56:20 +05:30
Sourabh Singh Tomar 9d2da6759b Revert "[DebugInfo] Emit DW_OP_implicit_value for Floating point constants"
This reverts commit 6b55a95898.
Temporal revert due to a failing/assertion in test case in Sparc backend.
`test/DebugInfo/Sparc/subreg.ll`
Seen in lot of bots, for instance in:
`http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/24679`
2020-07-23 08:50:01 +05:30
Sourabh Singh Tomar 6b55a95898 [DebugInfo] Emit DW_OP_implicit_value for Floating point constants
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
2020-07-23 07:21:49 +05:30
David Blaikie 5c2451785d DebugInfo: Use debug_line.dwo for debug_macro.dwo
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
2020-07-22 14:06:33 -07:00
OCHyams ce6de3747b [DebugInfo] Drop location ranges for variables which exist entirely outside the variable's scope
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
2020-07-22 12:45:21 +01:00
David Blaikie 2892bec5bc DebugInfo: Add missing comment from llvm/test/DebugInfo/X86/debug-macro-dwo.ll
Meant to include this in 63a45091e5
2020-07-21 13:36:50 -07:00