Commit Graph

286 Commits

Author SHA1 Message Date
Paul Robinson c7046c91cd Silence a conversion warning after r366887. NFC
llvm-svn: 366906
2019-07-24 14:15:02 +00:00
Igor Kudrin 3daefb0744 [DWARF][NFC] Add constants for reserved values of an initial length field.
Differential Revision: https://reviews.llvm.org/D65039

llvm-svn: 366887
2019-07-24 11:34:29 +00:00
Jonas Devlieghere 0e7ba06e82 [DWARF] Add more error handling to debug line parser.
This patch exnteds the error handling in the debug line parser to get
rid of the existing MD5 assertion. I want to reuse the debug line parser
from LLVM in LLDB where we cannot crash on invalid input.

Differential revision: https://reviews.llvm.org/D64544

llvm-svn: 366762
2019-07-22 23:23:34 +00:00
Igor Kudrin f48bc01812 [DWARF] Fix the reserved values for unit length in DWARFDebugLine.
The DWARF3 documentation had inconsistency concerning the reserved range
for unit length values. The issue was fixed in DWARF4.

Differential Revision: https://reviews.llvm.org/D64622

llvm-svn: 366190
2019-07-16 07:01:08 +00:00
Nico Weber 51a52b5893 PDB HashTable: Move TraitsT from class parameter to the methods that need it
The traits object is only used by a few methods. Deserializing a hash
table and walking it is possible without the traits object, so it
shouldn't be required to build a dummy object for that use case.

The TraitsT object used to be a function template parameter before
r327647, this restores it to that state.

This makes it clear that the traits object isn't needed at all in 1 of
the current 3 uses of HashTable (and I am going to add another use that
doesn't need it), and that the default PdbHashTraits isn't used outside
of tests.

While here, also re-enable 3 checks in the test that were commented out
(which requires making HashTableInternals templated and giving FooBar
an operator==).

No intended behavior change.

Differential Revision: https://reviews.llvm.org/D64640

llvm-svn: 365974
2019-07-12 23:30:55 +00:00
Fangrui Song 493a120259 [DebugInfo] Simplify GSYM::AddressRange and GSYM::AddressRanges
Delete unnecessary getters of AddressRange.
Simplify AddressRange::size(): Start <= End check should be checked in an upper layer.
Delete isContiguousWith() that doesn't make sense.
Simplify AddressRanges::insert. Delete commented code. Fix it when more than 1 ranges are to be deleted.
Delete trailing newline.

llvm-svn: 364637
2019-06-28 10:06:11 +00:00
Fangrui Song e662b6985a [DebugInfo] GSYM cleanups after D63104/r364427
llvm-svn: 364634
2019-06-28 08:58:05 +00:00
Greg Clayton 044776bf5d Add GSYM utility files along with unit tests.
The full GSYM patch started with: https://reviews.llvm.org/D53379

In that patch we wanted to split up getting GSYM into the LLVM code base so we are not committing too much code at once.

This is a first in a series of patches where I only add the foundation classes along with complete unit tests. They provide the foundation for encoding and decoding a GSYM file.

File entries are defined in llvm::gsym::FileEntry. This class splits the file up into a directory and filename represented by uniqued string table offsets. This allows all files that are referred to in a GSYM file to be encoded as 1 based indexes into a global file table in the GSYM file.

Function information in stored in llvm::gsym::FunctionInfo. This object represents a contiguous address range that has a name and range with an optional line table and inline call stack information.

Line table entries are defined in llvm::gsym::LineEntry. They store only address, file and line information to keep the line tables simple and allows the information to be efficiently encoded in a subsequent patch.

Inline information is defined in llvm::gsym::InlineInfo. These structs store the name of the inline function, along with one or more address ranges, and the file and line that called this function. They also contain any child inline information.

There are also utility classes for address ranges in llvm::gsym::AddressRange, and string table support in llvm::gsym::StringTable which are simple classes.

The unit tests test all the APIs on these simple classes so they will be ready for the next patches where we will create GSYM files and parse GSYM files.

Differential Revision: https://reviews.llvm.org/D63104

llvm-svn: 364427
2019-06-26 14:09:09 +00:00
Jason Liu 552fda839a Fix DWARF DebugInfo unit test errors when cross-compiling
Summary:
When building with a Default Target set we can experience issues
in the DWARF DebugInfo unit tests because:

They assume we can generate object files for the host platform.
Some tests assume the endianess of the target we are generating
DWARF for and the host match.

This patch correct these issues by ensuring the tests which
generate objects in memory are run with respect to
LVM_DEFAULT_TARGET_TRIPLE and it's endianess.

We also make sure we don't use the hosts address size for line test
and split the triple util function in DwarfUtils into a version
that takes an address size and one that doesn't.

See also for discussion:
http://lists.llvm.org/pipermail/llvm-dev/2019-March/131212.html

Patch by: daltenty

Differential Revision: https://reviews.llvm.org/D62084

llvm-svn: 362454
2019-06-03 22:22:03 +00:00
Nico Weber e577be4ed1 [PDB] Fix hash function used to write /src/headerblock
lld-link used to write PDB files that DIA couldn't recover natvis
files from if:

- The global strings table was > 64kiB
- There were at least 3 natvis files

The cause was that the hash function for the /src/headerblock stream
was incorrect: It needs to be truncated to 16 bit.

If the global strings table was <= 64kiB, truncating to 16 bit is a
no-op, so this wasn't needed for small programs.

If there are only 1 or 2 natvis files, then the growth strategy in
HashTable::grow() would mean the hash table would have 2 buckets (for 1
natvis file) or 4 buckets (for 4 natvis files), and since the hash
function is used modulo number of buckets, and since 2 and 4 divide
0x10000, the missing `% 0x10000` is a no-op there too. For 3 natvis
files, the hash table grows to 6 buckets, which has a factor that's not
common with 0x10000 and the difference starts to matter.

Fixes PR41626.

Differential Revision: https://reviews.llvm.org/D61277

llvm-svn: 359515
2019-04-29 23:09:35 +00:00
Fangrui Song f56a436891 [DWARF] Fix DWARFVerifier::DieRangeInfo::contains
It didn't handle empty LHS correctly. If two ranges of LHS were
contiguous and jointly contained one range of RHS, it could also be incorrect.

DWARFAddressRange::contains can be removed and its tests can be merged into DWARFVerifier::DieRangeInfo::contains

llvm-svn: 358387
2019-04-15 10:02:36 +00:00
Fangrui Song b93de4cd26 [DWARF] Fix DWARFVerifier::DieRangeInfo::intersects
It was incorrect if RHS had more than 1 ranges and one of the ranges interacted with *this

llvm-svn: 358376
2019-04-15 08:30:10 +00:00
Reid Kleckner e10d00419a [codeview] Remove Type member from CVRecord
Summary:
Now CVType and CVSymbol are effectively type-safe wrappers around
ArrayRef<uint8_t>. Make the kind() accessor load it from the
RecordPrefix, which is the same for types and symbols.

Reviewers: zturner, aganea

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60018

llvm-svn: 357658
2019-04-04 00:28:48 +00:00
Jonas Devlieghere bb111152b7 [DWARFFormValue] Cleanup DWARFFormValue interface. (NFC)
DWARFFormValues can be created from a data extractor or by passing its
value directly. Until now this was done by member functions that
modified an existing object's internal state. This patch replaces a
subset of these methods with static method that return a new
DWARFFormValue.

llvm-svn: 354941
2019-02-27 00:58:09 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Jonas Devlieghere 7323259de8 [DebugInfo] Define base function on DWARFDie reverse iterators
This defines member function base on the specialization of
std::reverse_iterator for DWARFDie::iterator as required by C++
[reverse.iter.conv].

This fixes unit test DWARFDebugInfoTest.cpp under EXPENSIVE_CHECKS which
currently can't be built due to GNU C++ Library calling this member
function in debug mode.

This fixes https://llvm.org/PR38785

Patch by: Eugene Sharygin

Differential revision: https://reviews.llvm.org/D53792

llvm-svn: 345621
2018-10-30 18:25:28 +00:00
Aleksandr Urakov c43e086c74 Revert "Revert "[PDB] Extend IPDBSession's interface to retrieve frame data""
This reverts commit 466ce67d6ec444962e5cc0136243c16a453190c0.

llvm-svn: 345010
2018-10-23 08:14:53 +00:00
Aleksandr Urakov 738df2de7f Revert "[PDB] Extend IPDBSession's interface to retrieve frame data"
This reverts commit b5c7e2f9a4dbb34e3667c4bb4972735eadd3247a.

llvm-svn: 344909
2018-10-22 15:30:48 +00:00
Aleksandr Urakov d4a82f6f74 [PDB] Extend IPDBSession's interface to retrieve frame data
Summary:
This patch just extends the `IPDBSession` interface to allow retrieving
of frame data through it, and adds an implementation over DIA. It is needed
for an implementation (for now with DIA) of the conversion from FPO programs
to DWARF expressions mentioned in D53086.

Reviewers: zturner, asmith, rnk

Reviewed By: asmith

Subscribers: mgorny, aprantl, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D53324

llvm-svn: 344886
2018-10-22 07:18:08 +00:00
Zachary Turner b7471814cf Fix function signature to actually be an override.
llvm-svn: 342496
2018-09-18 16:58:17 +00:00
Nico Weber 1739dbf6a6 Introduce explicit add_unittest_with_input_files target for tests that use llvm::getInputFileDirectory()
Using llvm::getInputFileDirectory() in unit tests is discouraged, so require an explicit opt-in.
This way, cmake also writes ~60 fewer unused files to disk.

Differential Revision: https://reviews.llvm.org/D52095

llvm-svn: 342248
2018-09-14 17:34:46 +00:00
Zachary Turner cae734588f [PDB] Change uint32_t to SymIndex wherever it makes sense.
Although it's just a typedef, it helps for readability.  NFC.

llvm-svn: 341863
2018-09-10 21:30:59 +00:00
Fangrui Song 95dd7a25ba Quick fix for -DBUILD_SHARED_LIBS=on build after rL341502
libLLVMTestingSupport.so references a symbol in utils/unittest/UnitTestMain/TestMain.cpp (a layering issue) and will cause a link error because of -Wl,-z,defs (cmake/modules/HandleLLVMOptions.cmake)

Waiting zturner for a better fix.

llvm-svn: 341580
2018-09-06 19:51:20 +00:00
Zachary Turner d62d052c70 Fix a warning.
llvm-svn: 341561
2018-09-06 16:34:56 +00:00
Zachary Turner 7999b4fa48 [PDB] Refactor the PDB symbol classes to fix a reuse bug.
The way DIA SDK works is that when you request a symbol, it
gets assigned an internal identifier that is unique for the
life of the session.  You can then use this identifier to
get back the same symbol, with all of the same internal state
that it had before, even if you "destroyed" the original
copy of the object you had.

This didn't work properly in our native implementation, and
if you destroyed an object for a particular symbol, then
requested the same symbol again, it would get assigned a new
ID and you'd get a fresh copy of the object.  In order to fix
this some refactoring had to happen to properly reuse cached
objects.  Some unittests are added to verify that symbol
reuse is taking place, making use of the new unittest input
feature.

llvm-svn: 341503
2018-09-05 23:30:38 +00:00
Reid Kleckner bd5d71229d [codeview] Use push_macro to avoid conflicts instead of a prefix
Summary:
This prefix was added in r333421, and it changed our dumper output to
say things like "CVRegEAX" instead of just "EAX". That's a functional
change that I'd rather avoid.

I tested GCC, Clang, and MSVC, and all of them support #pragma
push_macro. They don't issue warnings whem the macro is not defined
either.

I don't have a Mac so I can't test the real termios.h header, but I
looked at the termios.h sources online and looked for other conflicts.
I saw only the CR* macros, so those are the ones we work around.

Reviewers: zturner, JDevlieghere

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D50851

llvm-svn: 339907
2018-08-16 17:34:31 +00:00
Pavel Labath 2f0881160c [DebugInfo] Reduce debug_str_offsets section size
Summary:
The accelerator tables use the debug_str section to store their strings.
However, they do not support the indirect method of access that is
available for the debug_info section (DW_FORM_strx et al.).

Currently our code is assuming that all strings can/will be referenced
indirectly, and puts all of them into the debug_str_offsets section.
This is generally true for regular (unsplit) dwarf, but in the DWO case,
most of the strings in the debug_str section will only be used from the
accelerator tables. Therefore the contents of the debug_str_offsets
section will be largely unused and bloating the main executable.

This patch rectifies this by teaching the DwarfStringPool to
differentiate between strings accessed directly and indirectly. When a
user inserts a string into the pool it has to declare whether that
string will be referenced directly or not. If at least one user requsts
indirect access, that string will be assigned an index ID and put into
debug_str_offsets table. Otherwise, the offset table is skipped.

This approach reduces the overall binary size (when compiled with
-gdwarf-5 -gsplit-dwarf) in my tests by about 2% (debug_str_offsets is
shrunk by 99%).

Reviewers: probinson, dblaikie, JDevlieghere

Subscribers: aprantl, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D49493

llvm-svn: 339122
2018-08-07 09:54:52 +00:00
Paul Robinson 7f33094486 [DebugInfo/DWARF] [2/4] Type units no longer in a std::deque. NFC
This is patch 2 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 2 takes the existing std::deque<DWARFUnitSection> for type units
and makes it a simple DWARFUnitSection, simplifying the handling of
type units and making it more consistent with compile units.

Differential Revision: https://reviews.llvm.org/D49742

llvm-svn: 338629
2018-08-01 20:46:46 +00:00
Paul Robinson 143eaeab53 [DebugInfo/DWARF] [1/4] De-templatize DWARFUnitSection. NFC
This is patch 1 of 4 NFC refactorings to handle type units and compile
units more consistently and with less concern about the object-file
section that they came from.

Patch 1 replaces the templated DWARFUnitSection with a non-templated
version. That is, instead of being a SmallVector of pointers to a
specific unit kind, it is not a SmallVector of pointers to the base
class for both type and compile units.  Virtual methods are magic.

Differential Revision: https://reviews.llvm.org/D49741

llvm-svn: 338628
2018-08-01 20:43:47 +00:00
Jonas Devlieghere 3a04bea91a [DebugInfo] Have custom std::reverse_iterator<DWARFDie>
The DWARFDie is a lightweight utility wrapper that stores a pointer to a
compile unit and a debug info entry. Currently, its iterator (used for
walking over its children) stores a DWARFDie and returns a const
reference when dereferencing it.

When the iterator is modified (by incrementing or decrementing it), this
reference becomes invalid. This was happening when calling reverse on
it, because the std::reverse_iterator is keeping a temporary copy of the
iterator (see
https://en.cppreference.com/w/cpp/iterator/reverse_iterator for a good
illustration).

The relevant code in libcxx:

  reference operator*() const {_Iter __tmp = current; return *--__tmp;}

When dereferencing the reverse iterator, we decrement and return a
reference to a DWARFDie stored in the stack frame of this function,
resulting in UB at runtime.

This patch specifies the std::reverse_iterator for DWARFDie to do the
right thing.

Differential revision: https://reviews.llvm.org/D49679

llvm-svn: 338506
2018-08-01 10:24:17 +00:00
Alexandre Ganea ee8a720051 [CodeView] Minimal support for S_UNAMESPACE records
Differential Revision: https://reviews.llvm.org/D50007

llvm-svn: 338417
2018-07-31 19:15:50 +00:00
Pavel Labath 7bfa5d6544 dwarfgen: Add support for generating the debug_str_offsets section, take 3
Previous version of this patch failed on darwin targets because of
different handling of cross-debug-section relocations. This fixes the
tests to emit the DW_AT_str_offsets_base attribute correctly in both
cases. Since doing this is a non-trivial amount of code, and I'm going
to need it in more than one test, I've added a helper function to the
dwarfgen DIE class to do it.

Original commit message follows:

The motivation for this is D49493, where we'd like to test details of
debug_str_offsets behavior which is difficult to trigger from a
traditional test.

This adds the plubming necessary for dwarfgen to generate this section.
The more interesting changes are:
- I've moved emitStringOffsetsTableHeader function from DwarfFile to
  DwarfStringPool, so I can generate the section header more easily from
  the unit test.
- added a new addAttribute overload taking an MCExpr*. This is used to
  generate the DW_AT_str_offsets_base, which links a compile unit to the
  offset table.

I've also added a basic test for reading and writing DW_form_strx forms.

Reviewers: dblaikie, JDevlieghere, probinson

Subscribers: llvm-commits, aprantl

Differential Revision: https://reviews.llvm.org/D49670

llvm-svn: 338031
2018-07-26 14:36:07 +00:00
Pavel Labath fac87b3dd7 dwarfgen: Don't create an AsmPrinter with an invalid ObjFile lowering
The AsmPrinter created in the tests contained an uninitialized
TargetLoweringObjectFile. Things mostly worked regardless, because we
used a separate instance of that class to specify sections to emit.

This rearanges the object construction order so that we can avoid
creating two lowering objects. Instead, we properly initialize the
object in the AsmPrinter, and have the DWARF generator store a pointer
to it.

llvm-svn: 338026
2018-07-26 13:16:06 +00:00
Pavel Labath da3c4fb5fe Revert "dwarfgen: Add support for generating the debug_str_offsets section, take 2"
This reverts commit r337933. The build error is fixed but the test now
fails on the darwin buildbots. Investigating...

llvm-svn: 337935
2018-07-25 16:34:43 +00:00
Pavel Labath 78ab659bb4 dwarfgen: Add support for generating the debug_str_offsets section, take 2
This recommits r337910 after fixing an "ambiguous call to addAttribute"
error with some compilers (gcc circa 4.9 and MSVC). It seems that these
compilers will consider a "false -> pointer" conversion during overload
resolution. This creates ambiguity because one I added an overload which
takes a MCExpr * as an argument.

I fix this by making the new overload take MCExpr&, which avoids the
conversion. It also documents the fact that we expect a valid MCExpr
object.

Original commit message follows:

The motivation for this is D49493, where we'd like to test details of
debug_str_offsets behavior which is difficult to trigger from a
traditional test.

This adds the plubming necessary for dwarfgen to generate this section.
The more interesting changes are:
- I've moved emitStringOffsetsTableHeader function from DwarfFile to
  DwarfStringPool, so I can generate the section header more easily from
  the unit test.
- added a new addAttribute overload taking an MCExpr*. This is used to
  generate the DW_AT_str_offsets_base, which links a compile unit to the
  offset table.

I've also added a basic test for reading and writing DW_form_strx forms.

Reviewers: dblaikie, JDevlieghere, probinson

Subscribers: llvm-commits, aprantl

Differential Revision: https://reviews.llvm.org/D49670

llvm-svn: 337933
2018-07-25 15:33:32 +00:00
Pavel Labath b4e17c29dd Revert "dwarfgen: Add support for generating the debug_str_offsets section"
This reverts commit r337910 as it's generating "ambiguous call to
addAttribute" errors on some bots.

Will resubmit once I get a chance to look into the problem.

llvm-svn: 337924
2018-07-25 12:52:30 +00:00
Pavel Labath 7a59e3bf37 dwarfgen: Add support for generating the debug_str_offsets section
Summary:
The motivation for this is D49493, where we'd like to test details of
debug_str_offsets behavior which is difficult to trigger from a
traditional test.

This adds the plubming necessary for dwarfgen to generate this section.
The more interesting changes are:
- I've moved emitStringOffsetsTableHeader function from DwarfFile to
  DwarfStringPool, so I can generate the section header more easily from
  the unit test.
- added a new addAttribute overload taking an MCExpr*. This is used to
  generate the DW_AT_str_offsets_base, which links a compile unit to the
  offset table.

I've also added a basic test for reading and writing DW_form_strx forms.

Reviewers: dblaikie, JDevlieghere, probinson

Subscribers: llvm-commits, aprantl

Differential Revision: https://reviews.llvm.org/D49670

llvm-svn: 337910
2018-07-25 11:55:59 +00:00
Jonas Devlieghere 3f27e57ade [DebugInfo] Make children iterator bidirectional
Make the DIE iterator bidirectional so we can move to the previous
sibling of a DIE.

Differential revision: https://reviews.llvm.org/D49173

llvm-svn: 336823
2018-07-11 17:11:11 +00:00
Zachary Turner ee8010abe3 Move some code from PDBFileBuilder to MSFBuilder.
The code to emit the pieces of the MSF file were actually in
PDBFileBuilder.  Move this to MSFBuilder so that we can
theoretically emit an MSF without having a PDB file.

llvm-svn: 335789
2018-06-27 21:18:15 +00:00
Jonas Devlieghere 43dce3edbe [CodeView] Add prefix to CodeView registers.
Adds CVReg to CodeView register names to prevent a duplicate symbol with
CR3 defined in termios.h, as suggested by Zachary on the mailing list.

http://lists.llvm.org/pipermail/llvm-dev/2018-May/123372.html

Differential revision: https://reviews.llvm.org/D47478

rdar://39863705

llvm-svn: 333421
2018-05-29 14:35:34 +00:00
James Henderson 004b729ed1 [DWARF] Refactor callback usage for .debug_line error handling
Change the "recoverable" error callback to take an Error instaed of a
string.

Reviewed by: JDevlieghere

Differential Revision: https://reviews.llvm.org/D46831

llvm-svn: 332845
2018-05-21 15:30:54 +00:00
Peter Collingbourne f7b81db715 MC: Change the streamer ctors to take an object writer instead of a stream. NFCI.
The idea is that a client that wants split dwarf would create a
specific kind of object writer that creates two files, and use it to
create the streamer.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47050

llvm-svn: 332749
2018-05-18 18:26:45 +00:00
Nico Weber 9668e45b61 Inline a few CMake variables into their only uses.
No behavior change. Makes unittests CMakeLists.txt files more self-consistent.

llvm-svn: 332280
2018-05-14 19:23:31 +00:00
Simon Pilgrim affbc99bea Fix Wdocumentation warnings. NFCI.
llvm-svn: 332239
2018-05-14 12:22:30 +00:00
James Henderson 198a87c8f3 [DWARF] Remove unused member and fix(?) the unit-tests on big endian hosts
I can't verified the fix on a big endian host, so I'm not 100% certain it
will work.

llvm-svn: 331986
2018-05-10 14:36:24 +00:00
Roman Lebedev 85343925d7 [DWARF] DwarfGenerator.h LineTable: explicitly mark DG as unused
Just want to unbreak the build.

llvm-svn: 331984
2018-05-10 14:16:45 +00:00
Roman Lebedev e1b0e29e1e [DWARF] dwarfgen::LineTable::writeData(): pacify -Wcovered-switch-default
llvm-svn: 331983
2018-05-10 14:16:41 +00:00
Roman Lebedev a68aee07d5 [DWARF] DWARFDebugLineTest: fix a few more signed/unsigned mismatch warnings
llvm-svn: 331982
2018-05-10 14:16:37 +00:00
James Henderson 11a9de74c9 Fix signed/unsigned comparison warning and print format
The print format was causing at least 2 unit-test failures from r331971.

The signed/unsigned comparison warnings only appeared to affect two lines but
it was unclear whether it might just pop up on other lines, so I have been
explicit in all the literals in the tests.

There were other bot unit-test failures that I am still investigating.

llvm-svn: 331978
2018-05-10 12:15:43 +00:00
James Henderson a3acf99e59 [DWARF] Rework debug line parsing to use llvm::Error and callbacks
Reviewed by: dblaikie, JDevlieghere, espindola

Differential Revision: https://reviews.llvm.org/D44560

Summary:
The .debug_line parser previously reported errors by printing to stderr and
return false. This is not particularly helpful for clients of the library code,
as it prevents them from handling the errors in a manner based on the calling
context. This change switches to using llvm::Error and callbacks to indicate
what problems were detected during parsing, and has updated clients to handle
the errors in a location-specific manner. In general, this means that they
continue to do the same thing to external users. Below, I have outlined what
the known behaviour changes are, relating to this change.

There are two levels of "errors" in the new error mechanism, to broadly
distinguish between different fail states of the parser, since not every
failure will prevent parsing of the unit, or of subsequent unit. Malformed
table errors that prevent reading the remainder of the table (reported by
returning them) and other minor issues representing problems with parsing that
do not prevent attempting to continue reading the table (reported by calling a
specified callback funciton). The only example of this currently is when the
last sequence of a unit is unterminated. However, I think it would be good to
change the handling of unrecognised opcodes to report as minor issues as well,
rather than just printing to the stream if --verbose is used (this would be a
subsequent change however).

I have substantially extended the DwarfGenerator to be able to handle
custom-crafted .debug_line sections, allowing for comprehensive unit-testing
of the parser code. For now, I am just adding unit tests to cover the basic
error reporting, and positive cases, and do not currently intend to test every
part of the parser, although the framework should be sufficient to do so at a
later point.

Known behaviour changes:
  - The dump function in DWARFContext now does not attempt to read subsequent
  tables when searching for a specific offset, if the unit length field of a
  table before the specified offset is a reserved value.
  - getOrParseLineTable now returns a useful Error if an invalid offset is
  encountered, rather than simply a nullptr.
  - The parse functions no longer use `WithColor::warning` directly to report
  errors, allowing LLD to call its own warning function.
  - The existing parse error messages have been updated to not specifically
  include "warning" in their message, allowing consumers to determine what
  severity the problem is.
  - If the line table version field appears to have a value less than 2, an
  informative error is returned, instead of just false.
  - If the line table unit length field uses a reserved value, an informative
  error is returned, instead of just false.
  - Dumping of .debug_line.dwo sections is now implemented the same as regular
  .debug_line sections.
  - Verbose dumping of .debug_line[.dwo] sections now prints the prologue, if
  there is a prologue error, just like non-verbose dumping.

As a helper for the generator code, I have re-added emitInt64 to the
AsmPrinter code. This previously existed, but was removed way back in r100296,
presumably because it was dead at the time.

This change also requires a change to LLD, which will be committed separately.

llvm-svn: 331971
2018-05-10 10:51:33 +00:00