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
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
This avoids allocating a few KB of heap memory on startup, and instead
allocates these maps lazily. I noticed this while profiling LLD.
llvm-svn: 357192
Before, empty debug streams were written as 8 bytes (4 bytes signature + 4 bytes for the GlobalRefs count).
With this patch, unused empty streams aren't emitted anymore. Modules now encode 65535 as an 'unused stream' value, by convention.
Also fix the * Linker * contrib section which wasn't correctly emitted previously.
Differential Revision: https://reviews.llvm.org/D59502
llvm-svn: 356395
Summary:
Swift now generates PDBs for debugging on Windows. llvm and lldb
need a language enumerator value too properly handle the output
emitted by swiftc.
Subscribers: jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59231
llvm-svn: 355882
That patch is the fix for https://bugs.llvm.org/show_bug.cgi?id=40703
"wrong line number info for obj file compiled with -ffunction-sections"
bug. The problem happened with only .o files. If object file contains
several .text sections then line number information showed incorrectly.
The reason for this is that DwarfLineTable could not detect section which
corresponds to specified address(because address is the local to the
section). And as the result it could not select proper sequence in the
line table. The fix is to pass SectionIndex with the address. So that it
would be possible to differentiate addresses from various sections. With
this fix llvm-objdump shows correct line numbers for disassembled code.
Differential review: https://reviews.llvm.org/D58194
llvm-svn: 354972
When type streams with forward references were merged using GHashes, cycles
were introduced in the debug info. This was caused by
GlobalTypeTableBuilder::insertRecordAs() not inserting the record on the second
pass, thus yielding an empty ArrayRef at that record slot. Later on, upon PDB
emission, TpiStreamBuilder::commit() would skip that empty record, thus
offseting all indices that came after in the stream.
This solution comes in two steps:
1. Fix the hash calculation, by doing a multiple-step resolution, iff there are
forward references in the input stream.
2. Fix merge by resolving with multiple passes, therefore moving records with
forward references at the end of the stream.
This patch also adds support for llvm-readoj --codeview-ghash.
Finally, fix dumpCodeViewMergedTypes() which previously could reference deleted
memory.
Fixes PR40221
Differential Revision: https://reviews.llvm.org/D57790
llvm-svn: 353412
Summary:
This patch fixes access to fpo streams in native pdb from DbiStream and makes
code consistent with DbiStreamBuilder.
Patch By: leonid.mashinskiy
Reviewers: zturner, aleksandr.urakov
Reviewed By: zturner
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D56725
llvm-svn: 352615
PDBs contain several serialized hash tables. In the microsoft-pdb
repo published to support LLVM implementing PDB support, the
provided initializes the bucket count for the TPI and IPI streams
to the maximum size. This occurs in tpi.cpp L33 and tpi.cpp L398.
In the LLVM code for generating PDBs, these streams are created with
minimum number of buckets. This difference makes LLVM generated
PDBs slower for when used for debugging.
Patch by C.J. Hebert
Differential Revision: https://reviews.llvm.org/D56942
llvm-svn: 352117
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
VarStreamArray was built on the assumption that it is backed by a
StreamRef, and offset 0 of that StreamRef is the first byte of the first
record in the array.
This is a logical and intuitive assumption, but unfortunately we have
use cases where it doesn't hold. Specifically, a PDB module's symbol
stream is prefixed by 4 bytes containing a magic value, and the first
byte of record data in the array is actually at offset 4 of this byte
sequence.
Previously, we would just truncate the first 4 bytes and then construct
the VarStreamArray with the resulting StreamRef, so that offset 0 of the
underlying stream did correspond to the first byte of the first record,
but this is problematic, because symbol records reference other symbol
records by the absolute offset including that initial magic 4 bytes. So
if another record wants to refer to the first record in the array, it
would say "the record at offset 4".
This led to extremely confusing hacks and semantics in loading code, and
after spending 30 minutes trying to get some math right and failing, I
decided to fix this in the underlying implementation of VarStreamArray.
Now, we can say that a stream is skewed by a particular amount. This
way, when we access a record by absolute offset, we can use the same
values that the records themselves contain, instead of having to do
fixups.
Differential Revision: https://reviews.llvm.org/D55344
llvm-svn: 348499
Previously these were dropped. We now understand them sufficiently
well to start emitting them. From the debugger's perspective, this
now enables us to have debug info about typedefs (both global and
function-locally scoped)
Differential Revision: https://reviews.llvm.org/D55228
llvm-svn: 348306
Part of the patch to not build the hash map eagerly was omitted
due to a merge conflict. Add it back, which should fix the failing
tests.
llvm-svn: 348166
Summary:
This speeds up linking clang.exe/pdb with /DEBUG:GHASH by 31%, from
12.9s to 9.8s.
Symbol records are typically small (16.7 bytes on average), but we
processed them one at a time. CVSymbol is a relatively "large" type. It
wraps an ArrayRef<uint8_t> with a kind an optional 32-bit hash, which we
don't need. Before this change, each DbiModuleDescriptorBuilder would
maintain an array of CVSymbols, and would write them individually with a
BinaryItemStream.
With this change, we now add symbols that happen to appear contiguously
in bulk. For each .debug$S section (roughly one per function), we
allocate two copies, one for relocation, and one for realignment
purposes. For runs of symbols that go in the module stream, which is
most symbols, we now add them as a single ArrayRef<uint8_t>, so the
vector DbiModuleDescriptorBuilder is roughly linear in the number of
.debug$S sections (O(# funcs)) instead of the number of symbol records
(very large).
Some stats on symbol sizes for the curious:
PDB size: 507M
sym bytes: 316,508,016
sym count: 18,954,971
sym byte avg: 16.7
As future work, we may be able to skip copying symbol records in the
linker for realignment purposes if we make LLVM write them aligned into
the object file. We need to double check that such symbol records are
still compatible with link.exe, but if so, it's definitely worth doing,
since my profile shows we spend 500ms in memcpy in the symbol merging
code. We could potentially cut that in half by saving a copy.
Alternatively, we could apply the relocations *after* we iterate the
symbols. This would require some careful re-engineering of the
relocation processing code, though.
Reviewers: zturner, aganea, ruiu
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D54554
llvm-svn: 347687
In a previous patch, we pre-processed the TPI stream in order to build
the reverse mapping from nested type -> parent type so that we could
accurately reconstruct a DeclContext hierarchy.
However, there were some issues. An LF_NESTTYPE record is really just a
typedef, so although it happens to be used to indicate the name of the
nested type and referring to the global record which defines the type,
it is also used for every other kind of nested typedef. When we rebuild
the DeclContext hierarchy, we want it to be as accurate as possible,
which means that if we have something like:
struct A {
struct B {};
using C = B;
};
We don't want to create two CXXRecordDecls in the AST each with the
exact same definition. We just want to create one for B and then
define C as an alias to B. Previously, however, it would not be able
to distinguish between the two cases and it would treat A::B and
A::C as being two classes each with separate definitions. We address
the first half of improving the pre-processing logic so that only
actual definitions are treated this way.
Later, in a followup patch, we can handle the case of nested
typedefs since we're already going to be enumerating the field list
anyway and this patch introduces the general framework for
distinguishing between the two cases.
Differential Revision: https://reviews.llvm.org/D54357
llvm-svn: 346786
This change allows for link-time merging of debugging information from
Microsoft precompiled types OBJs compiled with cl.exe /Z7 /Yc and /Yu.
This fixes llvm.org/PR34278
Differential Revision: https://reviews.llvm.org/D45213
llvm-svn: 346154
This is mostly some cleanup done in the process of implementing
some basic support for types. I tried to split up the patch a
bit to get some of the NFC portion of the patch out into a separate
commit, and this is the result of that. It moves some code around,
deletes some spurious namespace qualifications, removes some
unnecessary header includes, forward declarations, etc.
llvm-svn: 344913
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
When we're on the last bucket the computation is tricky.
We were failing when the last bucket contained multiple
matches. Added a new test for this.
llvm-svn: 344081
We changed an ArrayRef<uint8_t> to an ArrayRef<uint32_t>, but
it needs to be an ArrayRef<support::ulittle32_t>.
We also change ArrayRef<> to FixedStreamArray<>. Technically
an ArrayRef<> will work, but it can cause a copy in the underlying
implementation if the memory is not contiguous, and there's no
reason not to use a FixedStreamArray<>.
Thanks to nemanjai@ and thakis@ for helping me track this down
and confirm the fix.
llvm-svn: 344063
Fix the following warning when compiling with clang (caused by commit
rL343951):
GlobalsStream.cpp:61:33: warning: comparison of integers of different
signs: 'int' and 'uint32_t'
This also avoids double evaluation of `GlobalsTable.HashBuckets.size()`.
llvm-svn: 343957
The Globals table is a hash table keyed on symbol name, so
it's possible to lookup symbols by name in O(1) time. Add
a function to the globals stream to do this, and add an option
to llvm-pdbutil to exercise this, then use it to write some
tests to verify correctness.
llvm-svn: 343951
These work a little differently because they are actually in
the globals stream and are treated as symbol records, even though
DIA presents them as types. So this also adds the necessary
infrastructure to cache records that live somewhere other than
the TPI stream as well.
llvm-svn: 343507
We didn't properly detect when a pointer was a member
pointer, and when that was the case we were not
properly returning class parent info. This caused
member pointers to render incorrectly in pretty mode.
However, we didn't even have pretty tests for pointers
in native mode, so those are also added now to ensure
this.
llvm-svn: 343393
This allows the native reader to find records of class/struct/
union type and dump them. This behavior is tested by using the
diadump subcommand against golden output produced by actual DIA
SDK on the same PDB file, and again using pretty -native to
confirm that we actually dump the classes. We don't find class
members or anything like that yet, for now it's just the class
itself.
llvm-svn: 342779
Some records point to an LF_CLASS, LF_UNION, LF_STRUCTURE, or LF_ENUM
which is a forward reference and doesn't contain complete debug
information. In these cases, we'd like to be able to quickly locate the
full record. The TPI stream stores an array of pre-computed record hash
values, one for each type record. If we pre-process this on startup, we
can build a mapping from hash value -> {list of possible matching type
indices}. Since hashes of full records are only based on the name and or
unique name and not the full record contents, we can then use forward
ref record to compute the hash of what *would* be the full record by
just hashing the name, use this to get the list of possible matches, and
iterate those looking for a match on name or unique name.
llvm-pdbutil is updated to resolve forward references for the purposes
of testing (plus it's just useful).
Differential Revision: https://reviews.llvm.org/D52283
llvm-svn: 342656
There were several issues with the previous implementation.
1) There were no tests.
2) We didn't support creating PDBSymbolTypePointer records for
builtin types since those aren't described by LF_POINTER
records.
3) We didn't support a wide enough variety of builtin types even
ignoring pointers.
This patch fixes all of these issues. In order to add tests,
it's helpful to be able to ignore the symbol index id hierarchy
because it makes the golden output from the DIA version not match
our output, so I've extended the dumper to disable dumping of id
fields.
llvm-svn: 342493
Previously we would dump the names of enum types, but not their
enumerator values. This adds support for enumerator values. In
doing so, we have to introduce a general purpose mechanism for
caching symbol indices of field list members. Unlike global
types, FieldList members do not have a TypeIndex. So instead,
we identify them by the pair {TypeIndexOfFieldList, IndexInFieldList}.
llvm-svn: 342415