2041 Commits

Author SHA1 Message Date
Igor Kudrin
75ae27f650 [DebugInfo] Print the actual value of an unknown section identifier.
This is a follow-up for D75609. As @dblaikie suggested, it prints
the actual number for an unknown section identifier when dumping
unit index sections.

Differential Revision: https://reviews.llvm.org/D75668
2020-03-06 21:46:04 +07:00
Igor Kudrin
a4fab2c27b [DebugInfo] Do not truncate 64-bit values when dumping CIEs and FDEs.
This fixes printing long values that might reside in CIE and FDE,
including offsets, lengths, and addresses.

Differential Revision: https://reviews.llvm.org/D73887
2020-03-05 17:37:28 +07:00
Igor Kudrin
6b87aa0046 [DebugInfo] Refine the condition to detect CIEs.
The condition was not accurate enough and could interpret some FDEs in
.eh_frame or 64-bit DWARF .debug_frame sections as CIEs. Even though
such FDEs are unlikely in a normal situation, the wrong interpretation
could hide an issue in a buggy generator.

Differential Revision: https://reviews.llvm.org/D73886
2020-03-05 17:37:09 +07:00
Igor Kudrin
0ceba89b0b [DebugInfo] Avoid crashing on an invalid section identifier.
A DWARFSectionKind is read from input. It is not validated on parsing,
so an unexpected value may result in reaching llvm_unreachable() in
DWARFUnitIndex::getColumnHeader() when dumping the index section.

Differential Revision: https://reviews.llvm.org/D75609
2020-03-05 10:54:43 +07:00
Greg Clayton
8024597fa7 Fix buildbots with merge that didn't happen for 4050b01ba9ece02721ec496383baee219ca8cc2b. 2020-03-04 19:28:24 -08:00
Greg Clayton
990fd897af Fix GSYM tests to run the yaml files and fix test failures on some machines.
YAML files were not being run during lit testing as there was no lit.local.cfg file. Once this was fixed, some buildbots would fail due to a StringRef that pointed to a std::string inside of a temporary llvm::Triple object. These issues are fixed here by making a local triple object that stays around long enough so the StringRef points to valid data. Fixed memory sanitizer bot bugs as well.

Differential Revision: https://reviews.llvm.org/D75390
2020-03-04 19:14:08 -08:00
Mitch Phillips
130c37bda0 Revert "Fix GSYM tests to run the yaml files and fix test failures on some machines."
This reverts commit 8d41f1a02369537cae1a7d00c0fa717fc3aca575.

This change broke the MSan buildbots - see comments in
https://reviews.llvm.org/D75390 for more information.
2020-03-04 10:21:54 -08:00
Pavel Labath
4b7edf8a76 Use new DWARFDataExtractor::getInitialLength in DWARFDebugFrame 2020-03-04 13:01:35 +01:00
Pavel Labath
5b780ab14f Use new DWARFDataExtractor::getInitialLength in DWARFDebugPubTable 2020-03-04 13:01:35 +01:00
Pavel Labath
0777f5891c Use new DWARFDataExtractor::getInitialLength in DWARFUnit 2020-03-04 13:01:35 +01:00
Pavel Labath
bd8f009db3 Use new DWARFDataExtractor::getInitialLength in DWARFVerifier 2020-03-04 13:01:34 +01:00
Pavel Labath
9ccd43f14c Use DWARFDataExtractor::getInitialLength in debug_aranges
Summary:
getInitialLength is a *DWARF*DataExtractor method so I had to "upgrade"
some DataExtractors to be able to make use of it.

Reviewers: ikudrin, jhenderson, probinson

Subscribers: aprantl, hiraditya, llvm-commits, dblaikie

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75535
2020-03-04 13:01:07 +01:00
Pavel Labath
34adeccc0f Use DWARFDataExtractor::getInitialLength in DWARFDebugAddr
Reviewers: ikudrin, jhenderson, probinson

Subscribers: hiraditya, dblaikie, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75532
2020-03-04 13:00:15 +01:00
David Blaikie
996af71606 DebugInfo: Separate different debug_macinfo contributions & print the offset of a contribution 2020-03-02 19:30:30 -08:00
Greg Clayton
1490382df1 Fix GSYM tests to run the yaml files and fix test failures on some machines.
YAML files were not being run during lit testing as there was no lit.local.cfg file. Once this was fixed, some buildbots would fail due to a StringRef that pointed to a std::string inside of a temporary llvm::Triple object. These issues are fixed here by making a local triple object that stays around long enough so the StringRef points to valid data. Also fixed an issue where strings for files in the file table could be added in opposite order due to parameters to function calls not having a strong ordering, which caused tests to fail. Added new arch specfic directories so when targets are not enabled, we continue to function just fine.

Differential Revision: https://reviews.llvm.org/D75390
2020-03-02 15:40:11 -08:00
Greg Clayton
29c6f36324 Revert "Fix GSYM tests to run the yaml files and fix test failures on some machines."
This reverts commit 57688350adea307e7bccb83b68a5b7333de31fd7.

Need to conditionalize for ARM targets, this is failing on machines that don't have ARM targets.
2020-03-02 13:07:58 -08:00
Greg Clayton
f5b15baf83 Fix GSYM tests to run the yaml files and fix test failures on some machines.
YAML files were not being run during lit testing as there was no lit.local.cfg file. Once this was fixed, some buildbots would fail due to a StringRef that pointed to a std::string inside of a temporary llvm::Triple object. These issues are fixed here by making a local triple object that stays around long enough so the StringRef points to valid data. Also fixed an issue where strings for files in the file table could be added in opposite order due to parameters to function calls not having a strong ordering, which caused tests to fail.

Differential Revision: https://reviews.llvm.org/D75390
2020-03-02 12:52:53 -08:00
Pavel Labath
b424382a42 [DWARF] Use DWARFDataExtractor::getInitialLength to parse debug_names
Summary:
In this patch I've done a slightly bigger rewrite to also remove the
hardcoded header lengths.

Reviewers: jhenderson, dblaikie, ikudrin

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75119
2020-03-02 11:21:23 +01:00
Pavel Labath
16b078b185 [DWARF] Use getInitialLength in range list parsing
Summary:
This could be considered obvious, but I am putting it up to illustrate
the usefulness/impact of the getInitialLength change.

Reviewers: dblaikie, jhenderson, ikudrin

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75117
2020-03-02 11:18:12 +01:00
Pavel Labath
b7a812f072 [DWARFDebugLine] Use new DWARFDataExtractor::getInitialLength
Summary:
The error messages change somewhat, but I believe the overall
informational value remains unchanged.

Reviewers: jhenderson, dblaikie, ikudrin

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75116
2020-03-02 11:14:29 +01:00
Igor Kudrin
cd7f9e3ce0 [DebugInfo] Fix parsing DWARF64 units in DWP.
The integrity check code allowed only DWARF32 units.

Differential Revision: https://reviews.llvm.org/D75178
2020-02-28 15:35:51 +07:00
Igor Kudrin
f473ff580e [DebugInfo] Avoid crashing when parsing an invalid unit header in DWP.
The integrity checks for index entries in DWARFUnitHeader::extract()
might cause the function to return before checking the state of an
Error object, which leads to a crash in runtime. The patch fixes the
issue by moving the checks in a safe place.

Differential Revision: https://reviews.llvm.org/D75177
2020-02-28 15:35:51 +07:00
Alexey Lapshin
35d0c4caae [Debuginfo][NFC] Unify error reporting routines inside DebugInfoDWARF.
Summary:
Error reporting in DebugInfoDWARF library currently done in three ways :

1. Direct calls to WithColor::error()/WithColor::warning()
2. ErrorPolicy defaultErrorHandler(Error E);
3. void dumpWarning(Error Warning);

additionally, other locations could have more variations:

lld/ELF/SyntheticSection.cpp
    if (Error e = cu->tryExtractDIEsIfNeeded(false)) {
      error(toString(sec) + ": " + toString(std::move(e)));

DebugInfo/DWARF/DWARFUnit.cpp
  if (Error e = tryExtractDIEsIfNeeded(CUDieOnly))
    WithColor::error() << toString(std::move(e));

Thus error reporting could look inconsistent. To have a consistent error
messages it is necessary to have a possibility to redefine error
reporting functions. This patch creates two handlers and allows to
redefine them. It also patches all places inside DebugInfoDWARF
to use these handlers.

The intention is always to use following handlers for error reporting
purposes inside DebugInfoDWARF:

DebugInfo/DWARF/DWARFContext.h

std::function<void(Error E)> RecoverableErrorHandler = WithColor::defaultErrorHandler;
std::function<void(Error E)> WarningHandler = WithColor::defaultWarningHandler;

This is last patch from series of patches: D74481, D74635, D75118.

Reviewers: jhenderson, dblaikie, probinson, aprantl, JDevlieghere

Reviewed By: jhenderson

Subscribers: grimar, hiraditya, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D74308
2020-02-27 18:32:40 +03:00
Alexey Lapshin
7caf79acd9 [DebugInfo][NFC] Remove handler with ErrorPolicy from DWARFContext.
Summary:
Current LLVM code base does not use error handler with ErrorPolicy.
This patch removes ErrorPolicy from DWARFContext.

This patch is extracted from the D74308.

Reviewers: jhenderson, dblaikie, grimar, aprantl, JDevlieghere

Reviewed By: grimar

Subscribers: hiraditya, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D75118
2020-02-27 00:42:37 +03:00
Pavel Labath
2993a0fb59 Introduce DWARFDataExtractor::getInitialLength
Summary:
This patch introduces a function to house the code needed to do the
DWARF64 detection dance. The function decodes the initial length field
and returns it as a pair containing the actual length, and the DWARF
encoding.

This patch does _not_ attempt to handle the problem of detecting lengths
which extend past the size of the section, or cases when reads of a
single contribution accidentally escape beyond its specified length, but
I think it's useful in its own right.

Reviewers: dblaikie, jhenderson, ikudrin

Subscribers: hiraditya, probinson, aprantl, JDevlieghere, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74560
2020-02-26 17:07:58 +01:00
Pavel Labath
87036fd412 Recommit "[DWARFDebugLine] Avoid dumping prologue members we did not parse"
The patch was reverted in 69da40033 because of test failures on windows.
The problem was the unpredictable order of some of the error messages,
which I've tried to strenghten in that patch.

It turns out this is not possible to do in verbose mode because there
the data is being writted as it is being parsed. No amount of flushing
(as I've done in the non-verbose mode) will help that. Indeed, even
without any buffering the warning messages can end in the middle of a
line in non-verbose mode.

In this patch, I have reverted the changes which tested the relative
position of the warning message, except for the messages about
unsupported initial length, which are the ones I really wanted to test,
and which do come out reasonably.

The original commit message was:

This patch if motivated by D74560, specifically the subthread about what
to print upon encountering reserved initial length values.

If the debug_line prologue has an unsupported version, we skip parsing
the rest of the data. If we encounter an reserved initial length field,
we don't even parse the version. However, we still print out all members
(with value 0) in the dump function.

This patch introduces early exits in the Prologue::dump function so that
we print only the fields that were parsed successfully. In case of an
unsupported version, we skip printing all subsequent prologue fields --
because we don't even know if this version has those fields. In case of a
reserved unit length, we don't print anything -- if the very first field
of the prologue is invalid, it's hard to say if we even have a prologue
to begin with.

Note that the user will still be able to see the invalid/reserved
initial length value in the error message. I've modified (reordered)
debug_line_invalid.test to show that the error message comes straight
after the debug_line offset. I've also added some flush() calls to the
dumping code to ensure this is the case in all situations (without that,
the warnings could get out of sync if the output was not a terminal -- I
guess this is why std::iostreams have the tie() function).

Reviewers: jhenderson, ikudrin, dblaikie

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75043
2020-02-26 16:42:25 +01:00
Michael Liao
467a5f54d7 Add missing dependency to fix shared library build. 2020-02-26 01:59:53 -05:00
Greg Clayton
75aaaf95b6 Add a llvm-gsymutil tool that can convert object files to GSYM and perform lookups.
Summary:
This patch creates the llvm-gsymutil binary that can convert object files to GSYM using the --convert <path> option. It can also dump and lookup addresses within GSYM files that have been saved to disk.

To dump a file:

llvm-gsymutil /path/to/a.gsym

To perform address lookups, like with atos, on GSYM files:

llvm-gsymutil --address 0x1000 --address 0x1100 /path/to/a.gsym

To convert a mach-o or ELF file, including any DWARF debug info contained within the object files:

llvm-gsymutil --convert /path/to/a.out --out-file /path/to/a.out.gsym

Conversion highlights:
- convert DWARF debug info in mach-o or ELF files to GSYM
- convert symbols in symbol table to GSYM and don't convert symbols that overlap with DWARF debug info
- extract UUID from object files
- extract .text (read + execute) section address ranges and filter out any DWARF or symbols that don't fall in those ranges.
- if .text sections are extracted, and if the last gsym::FunctionInfo object has no size, cap the size to the end of the section the function was contained in

Dumping GSYM files will dump all sections of the GSYM file in textual format.

Reviewers: labath, aadsm, serhiy.redko, jankratochvil, xiaobai, wallace, aprantl, JDevlieghere, jdoerfert

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74883
2020-02-25 21:11:05 -08:00
Pavel Labath
3ce422a57b Revert "[DWARFDebugLine] Avoid dumping prologue members we did not parse"
The changed test started failing on the windows bots. Reverting while I
investigate.

This reverts commit deb116ee0a5b80f61bc341ed68606dc5ad093569.
2020-02-25 17:58:50 +01:00
Pavel Labath
0028727768 [DWARFDebugLine] Avoid dumping prologue members we did not parse
Summary:
This patch if motivated by D74560, specifically the subthread about what
to print upon encountering reserved initial length values.

If the debug_line prologue has an unsupported version, we skip parsing
the rest of the data. If we encounter an reserved initial length field,
we don't even parse the version. However, we still print out all members
(with value 0) in the dump function.

This patch introduces early exits in the Prologue::dump function so that
we print only the fields that were parsed successfully. In case of an
unsupported version, we skip printing all subsequent prologue fields --
because we don't even know if this version has those fields. In case of a
reserved unit length, we don't print anything -- if the very first field
of the prologue is invalid, it's hard to say if we even have a prologue
to begin with.

Note that the user will still be able to see the invalid/reserved
initial length value in the error message. I've modified (reordered)
debug_line_invalid.test to show that the error message comes straight
after the debug_line offset. I've also added some flush() calls to the
dumping code to ensure this is the case in all situations (without that,
the warnings could get out of sync if the output was not a terminal -- I
guess this is why std::iostreams have the tie() function).

Reviewers: jhenderson, ikudrin, dblaikie

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D75043
2020-02-25 16:29:02 +01:00
Igor Kudrin
84c56f2c7c [DebugInfo] Fix printing CIE offsets in EH FDEs.
While the value of the CIE pointer field in a DWARF FDE record is
an offset to the corresponding CIE record from the beginning of
the section, for EH FDE records it is relative to the current offset.
Previously, we did not make that distinction when dumped both kinds
of FDE records and just printed the same value for the CIE pointer
field and the CIE offset; that was acceptable for DWARF FDEs but was
wrong for EH FDEs.

This patch fixes the issue by explicitly printing the offset of the
linked CIE object.

Differential Revision: https://reviews.llvm.org/D74613
2020-02-25 17:10:29 +07:00
Sourabh Singh Tomar
d95c06c4ad [DebugInfo]: Refactored Macinfo section consumption part to allow future
macro section dumping.

Summary: Previously macinfo infrastructure was using functions
names that were ambiguous i.e `getMacro/getMacroDWO` in a sense
of conveying stated intentions. This patch refactored them into more
reasonable `getDebugMacinfo/getDebugMacinfoDWO` names thus making
room for macro implementation.

Reviewers: aprantl, probinson, jini.susan.george, dblaikie

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D75037
2020-02-25 07:56:48 +05:30
Sourabh Singh Tomar
b4f51213cf Revert "[NFCI][DebugInfo]: Corrected a Typo."
This reverts commit 3e1090922a0b808f424ff424b744752b0d53a3ee
as per Paul Robinson's suggestion.
2020-02-21 01:15:09 +05:30
Igor Kudrin
36cf70c05c [DebugInfo] Read CIE pointer as a relocatable value.
The CIE pointer field of an FDE record contains an offset to
a corresponding CIE record. In object files, this value comes with
relocation because the value has to be fixed when a linker combines
the final section from multiple sources. In most object files there is
only one CIE record at offset 0 of the .debug_frame section, so reading
a relocated or a raw value makes no difference. However, in partially
linked object files there are multiple CIE records and the relocations
should be applied to recover the right offset value.

Differential Revision: https://reviews.llvm.org/D74612
2020-02-20 09:12:05 +07:00
Greg Clayton
76f7457508 Add an Offset field to the SourceLocation for LookupResult objects.
Summary:
The Offset provides the offset within the function in a SourceLocation struct. This allows us to show the byte offset within a function. We also track offsets within inline functions as well. Updated the lookup tests to verify the offset for functions and inline functions.

0x1000: main + 32 @ /tmp/main.cpp:45

Reviewers: labath, aadsm, serhiy.redko, jankratochvil, xiaobai, wallace, aprantl, JDevlieghere

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74680
2020-02-19 16:12:32 -08:00
Sourabh Singh Tomar
743f6f19e1 [NFCI][DebugInfo]: Corrected a Typo. 2020-02-17 14:50:32 +05:30
Greg Clayton
0f9e8cbf13 [NFC] Move ValidTextRanges out of DwarfTransformer and into GsymCreator and unify address is not in GSYM errors so all strings match. 2020-02-15 16:48:23 -08:00
Alexey Lapshin
4c1f969392 [Debuginfo][NFC] Remove usages of WithColor::error and WithColor::warning.
Summary:
This patch is extracted from D74308.

It patches all usages of WithColor::error() and WithColor::warning
in DebugInfoDWARF library.

Depends on D74481

Reviewers: jhenderson, dblaikie, probinson, aprantl, JDevlieghere

Reviewed By: JDevlieghere

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74635
2020-02-15 14:18:45 +03:00
Alexey Lapshin
d1dbbf13e4 [Debuginfo][NFC] Create common error handlers for DWARFContext.
Summary:
this review is extracted from D74308.

It creates two error handlers which allow to redefine error
reporting routine and should be used for all places
where errors are reported:

  std::function<void(Error)> RecoverableErrorHandler = defaultErrorHandler;
  std::function<void(Error)> WarningHandler = defaultWarningHandler;

It also creates accessors to above handlers which should be used to
report errors.

  function_ref<void(Error)> getRecoverableErrorHandler() {
    return RecoverableErrorHandler;
  }

  function_ref<void(Error)> getWarningHandler() { return WarningHandler; }

It patches all error reporting places inside DWARFContext and DWARLinker.

Reviewers: jhenderson, dblaikie, probinson, aprantl, JDevlieghere

Reviewed By: jhenderson, JDevlieghere

Subscribers: hiraditya, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D74481
2020-02-15 12:46:17 +03:00
Fangrui Song
13339a0dea [MCStreamer] De-capitalize EmitValue EmitIntValue{,InHex} 2020-02-14 23:08:40 -08:00
Fangrui Song
343c2a2b44 [MC] De-capitalize some MCStreamer::Emit* functions 2020-02-14 19:11:53 -08:00
Alexandre Ganea
ae05eb086d [Support] On Windows, ensure hardware_concurrency() extends to all CPU sockets and all NUMA groups
The goal of this patch is to maximize CPU utilization on multi-socket or high core count systems, so that parallel computations such as LLD/ThinLTO can use all hardware threads in the system. Before this patch, on Windows, a maximum of 64 hardware threads could be used at most, in some cases dispatched only on one CPU socket.

== Background ==
Windows doesn't have a flat cpu_set_t like Linux. Instead, it projects hardware CPUs (or NUMA nodes) to applications through a concept of "processor groups". A "processor" is the smallest unit of execution on a CPU, that is, an hyper-thread if SMT is active; a core otherwise. There's a limit of 32-bit processors on older 32-bit versions of Windows, which later was raised to 64-processors with 64-bit versions of Windows. This limit comes from the affinity mask, which historically is represented by the sizeof(void*). Consequently, the concept of "processor groups" was introduced for dealing with systems with more than 64 hyper-threads.

By default, the Windows OS assigns only one "processor group" to each starting application, in a round-robin manner. If the application wants to use more processors, it needs to programmatically enable it, by assigning threads to other "processor groups". This also means that affinity cannot cross "processor group" boundaries; one can only specify a "preferred" group on start-up, but the application is free to allocate more groups if it wants to.

This creates a peculiar situation, where newer CPUs like the AMD EPYC 7702P (64-cores, 128-hyperthreads) are projected by the OS as two (2) "processor groups". This means that by default, an application can only use half of the cores. This situation could only get worse in the years to come, as dies with more cores will appear on the market.

== The problem ==
The heavyweight_hardware_concurrency() API was introduced so that only *one hardware thread per core* was used. Once that API returns, that original intention is lost, only the number of threads is retained. Consider a situation, on Windows, where the system has 2 CPU sockets, 18 cores each, each core having 2 hyper-threads, for a total of 72 hyper-threads. Both heavyweight_hardware_concurrency() and hardware_concurrency() currently return 36, because on Windows they are simply wrappers over std:🧵:hardware_concurrency() -- which can only return processors from the current "processor group".

== The changes in this patch ==
To solve this situation, we capture (and retain) the initial intention until the point of usage, through a new ThreadPoolStrategy class. The number of threads to use is deferred as late as possible, until the moment where the std::threads are created (ThreadPool in the case of ThinLTO).

When using hardware_concurrency(), setting ThreadCount to 0 now means to use all the possible hardware CPU (SMT) threads. Providing a ThreadCount above to the maximum number of threads will have no effect, the maximum will be used instead.
The heavyweight_hardware_concurrency() is similar to hardware_concurrency(), except that only one thread per hardware *core* will be used.

When LLVM_ENABLE_THREADS is OFF, the threading APIs will always return 1, to ensure any caller loops will be exercised at least once.

Differential Revision: https://reviews.llvm.org/D71775
2020-02-14 10:24:22 -05:00
James Henderson
a0c4d6a1cc [DebugInfo] Error if unsupported address size detected in line table
Prior to this patch, if a DW_LNE_set_address opcode was parsed with an
address size (i.e. with a length after the opcode) of anything other 1,
2, 4, or 8, an llvm_unreachable would be hit, as the data extractor does
not support other values. This patch introduces a new error check that
verifies the address size is one of the supported sizes, in common with
other places within the DWARF parsing.

This patch also fixes calculation of a generated line table's size in
unit tests. One of the tests in this patch highlighted a bug introduced
in 1271cde4745, when non-byte operands were used as arguments for
extended or standard opcodes.

Reviewed by: dblaikie

Differential Revision: https://reviews.llvm.org/D73962
2020-02-14 11:08:12 +00:00
Francesco Petrogalli
236754c773 [build] Fix shared lib builds. 2020-02-13 22:09:52 +00:00
Greg Clayton
32dd03dc63 Fix buildbots that create shared libraries from GSYM library by adding a dependency on LLVMDebugInfoDWARF. 2020-02-13 11:43:07 -08:00
Greg Clayton
e962ea1e6c Fix buildbots by not using "and" and "not". 2020-02-13 11:35:43 -08:00
Greg Clayton
ccea019faf Add a DWARF transformer class that converts DWARF to GSYM.
Summary:
The DWARF transformer is added as a class so it can be unit tested fully.

The DWARF is converted to GSYM format and handles many special cases for functions:
- omit functions in compile units with 4 byte addresses whose address is UINT32_MAX (dead stripped)
- omit functions in compile units with 8 byte addresses whose address is UINT64_MAX (dead stripped)
- omit any functions whose high PC is <= low PC (dead stripped)
- StringTable builder doesn't copy strings, so we need to make backing copies of strings but only when needed. Many strings come from sections in object files and won't need to have backing copies, but some do.
- When a function doesn't have a mangled name, store the fully qualified name by creating a string by traversing the parent decl context DIEs and then. If we don't do this, we end up having cases where some function might appear in the GSYM as "erase" instead of "std::vector<int>::erase".
- omit any functions whose address isn't in the optional TextRanges member variable of DwarfTransformer. This allows object file to register address ranges that are known valid code ranges and can help omit functions that should have been dead stripped, but just had their low PC values set to zero. In this case we have many functions that all appear at address zero and can omit these functions by making sure they fall into good address ranges on the object file. Many compilers do this when the DWARF has a DW_AT_low_pc with a DW_FORM_addr, and a DW_AT_high_pc with a DW_FORM_data4 as the offset from the low PC. In this case the linker can't write the same address to both the high and low PC since there is only a relocation for the DW_AT_low_pc, so many linkers tend to just zero it out.

Reviewers: aprantl, dblaikie, probinson

Subscribers: mgorny, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74450
2020-02-13 10:48:37 -08:00
Igor Kudrin
2da0ac3ddb [DebugInfo] Fix dumping CIE ID in .eh_frame sections.
We do not keep the actual value of the CIE ID field, because it is
predefined, and use a constant when dumping a CIE record. The issue
was that the predefined value is different for .debug_frame and
.eh_frame sections, but we always printed the one which corresponds
to .debug_frame. The patch fixes that by choosing an appropriate
constant to print.

See the following for more information about .eh_frame sections:
https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html

Differential Revision: https://reviews.llvm.org/D73627
2020-02-13 15:42:14 +07:00
Sven van Haastregt
9c2e7dd6ae Add missing newlines at EOF; NFC 2020-02-12 15:57:25 +00:00
James Henderson
28d5339ea7 [DebugInfo] Add checks for v2 directory and file name table terminators
The DWARFv2-4 specification for the line table header states that the
include directories and file name tables both end with a single null
byte. Prior to this change, the parser did not detect if this byte was
missing, because it also stopped reading the tables once it reached the
prologue end, as claimed by the header_length field. This change adds a
check that the terminator has been seen at the end of each table.

Reviewed by: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D74413
2020-02-12 14:49:22 +00:00