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 a minor bug fix. Previously, if you tried to encode the RSP
register on the x86 platform, that might have succeeded and been encoded
incorrectly. However, no existing producer or consumer passes the x86_64
registers when targeting x86_32.
llvm-svn: 345879
The TypeIndex used by cl.exe is 0x103, which indicates a SimpleTypeMode
of NearPointer (note the absence of the bitness, normally pointers use a
mode of NearPointer32 or NearPointer64) and a SimpleTypeKind of void.
So this is basically a void*, but without a specified size, which makes
sense given how std::nullptr_t is defined.
clang-cl was actually not emitting *anything* for this. Instead, when we
encountered std::nullptr_t in a DIType, we would actually just emit a
TypeIndex of 0, which is obviously wrong.
std::nullptr_t in DWARF is represented as a DW_TAG_unspecified_type with
a name of "decltype(nullptr)", so we add that logic along with a test,
as well as an update to the dumping code so that we no longer print
void* when dumping 0x103 (which would previously treat Void/NearPointer
no differently than Void/NearPointer64).
Differential Revision: https://reviews.llvm.org/D53957
llvm-svn: 345811
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
Summary:
Before this change, LLVM would always describe locals on the stack as
being relative to some specific register, RSP, ESP, EBP, ESI, etc.
Variables in stack memory are pretty common, so there is a special
S_DEFRANGE_FRAMEPOINTER_REL symbol for them. This change uses it to
reduce the size of our debug info.
On top of the size savings, there are cases on 32-bit x86 where local
variables are addressed from ESP, but ESP changes across the function.
Unlike in DWARF, there is no FPO data to describe the stack adjustments
made to push arguments onto the stack and pop them off after the call,
which makes it hard for the debugger to find the local variables in
frames further up the stack.
To handle this, CodeView has a special VFRAME register, which
corresponds to the $T0 variable set by our FPO data in 32-bit. Offsets
to local variables are instead relative to this value.
This is part of PR38857.
Reviewers: hans, zturner, javed.absar
Subscribers: aprantl, hiraditya, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D52217
llvm-svn: 343543
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
Summary:
There are two registers encoded in the S_FRAMEPROC flags: one for locals
and one for parameters. The encoding is described by the
ExpandEncodedBasePointerReg function in cvinfo.h. Two bits are used to
indicate one of four possible values:
0: no register - Used when there are no variables.
1: SP / standard - Variables are stored relative to the standard SP
for the ISA.
2: FP - Variables are addressed relative to the ISA frame
pointer, i.e. EBP on x86. If realignment is required, parameters
use this. If a dynamic alloca is used, locals will be EBP relative.
3: Alternative - Variables are stored relative to some alternative
third callee-saved register. This is required to address highly
aligned locals when there are dynamic stack adjustments. In this
case, both the incoming SP saved in the standard FP and the current
SP are at some dynamic offset from the locals. LLVM uses ESI in
this case, MSVC uses EBX.
Most of the changes in this patch are to pass around the CPU so that we
can decode these into real, named architectural registers.
Subscribers: hiraditya
Differential Revision: https://reviews.llvm.org/D51894
llvm-svn: 341999
Following D50807, and heading towards D50664, this intermediary change does the following:
1. Upgrade all custom Error types in llvm/trunk/lib/DebugInfo/ to use the new StringError behavior (D50807).
2. Implement std::is_error_code_enum and make_error_code() for DebugInfo error enumerations.
3. Rename GenericError -> PDBError (the file will be renamed in a subsequent commit)
4. Update custom error messages to follow the same formatting: (\w\s*)+\.
5. Keep generic "file not found" (ENOENT) errors as they are in PDB code. Previously, there used to be a custom enumeration for that purpose.
6. Remove a few extraneous LF in log() implementations. Printing LF is a responsability at a higher level, not at the error level.
Differential Revision: https://reviews.llvm.org/D51499
llvm-svn: 341228
We have a function which switches on the type of a symbol record
to return a hardcoded offset into the record that contains the
symbol name. Not all symbols have names to begin with, and for
those records we return -1 for the offset.
Names are used for various things. Importantly for this particular
bug, a hash of the record name is used as a key for certain hash
tables which are serialied into the PDB file. One of these hash
tables is for the global symbol stream, which is basically a
collection of S_PROCREF symbols which contain the name of the
symbol, a module, and an address offset.
However, for S_PROCREF symbols, the function to return the offset
of the name was returning -1: basically it wasn't implemented.
As a result of this, all global symbols were hashing to the same
value, essentially it was as if every single global symbol's name
was the empty string.
This manifests in the VS debugger when you try to call a function
(global or member, doesn't matter) through the immediate window
and the debugger simply reports an error because it can't find the
function. This makes perfect sense, because it is hashing the name
for real, looking in the global symbol hash table, and there is only
1 entry there which corresponds to a symbol whose name is the empty
string.
Fixing this fixes the MSVC debugger in this case.
llvm-svn: 336024
Previously we emitted 20-byte SHA1 hashes. This is overkill
for identifying debug info records, and has the negative side
effect of making object files bigger and links slower. By
using only the last 8 bytes of a SHA1, we get smaller object
files and ~10% faster links.
This modifies the format of the .debug$H section by adding a new
value for the hash algorithm field, so that the linker will still
work when its object files have an old format.
Differential Revision: https://reviews.llvm.org/D46855
llvm-svn: 332669
The prefix includes type kind, which is important to preserve. Two
different type leafs can easily have the same interior record contents
as another type.
We ran into this issue in PR37492 where a bitfield type record collided
with a const modifier record. Their contents were bitwise identical, but
their kinds were different.
llvm-svn: 332664
When emitting CodeView debug information, compiler-generated thunk routines
should be emitted using S_THUNK32 symbols instead of S_GPROC32_ID symbols so
Visual Studio can properly step into the user code. This initial support only
handles standard thunk ordinals.
Differential Revision: https://reviews.llvm.org/D43838
llvm-svn: 330132
r327219 added wrappers to std::sort which randomly shuffle the container before
sorting. This will help in uncovering non-determinism caused due to undefined
sorting order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of
std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to
llvm::sort. Refer the comments section in D44363 for a list of all the
required patches.
llvm-svn: 330061
While reading Codeview records which contain variable-length encoded integers,
such as LF_BCLASS, LF_ENUMERATE, LF_MEMBER, LF_VBCLASS or LF_IVBCLASS,
the record's size would be improperly calculated in cases where the value was
indeed of a variable length (>= LF_NUMERIC). This caused a bad alignement on
the next record, which would/might crash later on.
Differential Revision: https://reviews.llvm.org/D45104
llvm-svn: 329659
Summary:
r327219 added wrappers to std::sort which randomly shuffle the container before sorting.
This will help in uncovering non-determinism caused due to undefined sorting
order of objects having the same key.
To make use of that infrastructure we need to invoke llvm::sort instead of std::sort.
Note: This patch is one of a series of patches to replace *all* std::sort to llvm::sort.
Refer the comments section in D44363 for a list of all the required patches.
Reviewers: echristo, zturner, samsonov
Reviewed By: echristo
Subscribers: JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D45134
llvm-svn: 328935
When investigating bugs in PDB generation, the first step is
often to do the same link with link.exe and then compare PDBs.
But comparing PDBs is hard because two completely different byte
sequences can both be correct, so it hampers the investigation when
you also have to spend time figuring out not just which bytes are
different, but also if the difference is meaningful.
This patch fixes a couple of cases related to string table emission,
hash table emission, and the order in which we emit strings that
makes more of our bytes the same as the bytes generated by MS PDBs.
Differential Revision: https://reviews.llvm.org/D44810
llvm-svn: 328348
NFC, this just renames some methods to better express what they
do, and also adds a few helper methods to add some symmetry to the
API in a few places (for example there was a getStringFromId but not
a getIdFromString method in the string table).
llvm-svn: 328221
This is still failing on a different bot this time due to some
issue related to hashing absolute paths. Reverting until I can
figure it out.
llvm-svn: 328014
The issue causing this to fail in certain configurations
should be fixed.
It was due to the fact that DIA apparently expects there to be
a null string at ID 1 in the string table. I'm not sure why this
is important but it seems to make a difference, so set it.
llvm-svn: 328002
Natvis is a debug language supported by Visual Studio for
specifying custom visualizers. The /NATVIS option is an
undocumented link.exe flag which will take a .natvis file
and "inject" it into the PDB. This way, you can ship the
debug visualizers for a program along with the PDB, which
is very useful for postmortem debugging.
This is implemented by adding a new "named stream" to the
PDB with a special name of /src/files/<natvis file name>
and simply copying the contents of the xml into this file.
Additionally, we need to emit a single stream named
/src/headerblock which contains a hash table of embedded
files to records describing them.
This patch adds this functionality, including the /NATVIS
option to lld-link.
Differential Revision: https://reviews.llvm.org/D44328
llvm-svn: 327895
Qualifiers on a pointer or reference type may apply to either the
pointee or the pointer itself. Consider 'const char *' and 'char *
const'. In the first example, the pointee data may not be modified
without casts, and in the second example, the pointer may not be updated
to point to new data.
In the general case, qualifiers are applied to types with LF_MODIFIER
records, which support the usual const and volatile qualifiers as well
as the __unaligned extension qualifier.
However, LF_POINTER records, which are used for pointers, references,
and member pointers, have flags for qualifiers applying to the
*pointer*. In fact, this is the only way to represent the restrict
qualifier, which can only apply to pointers, and cannot qualify regular
data types.
This patch causes LLVM to correctly fold 'const' and 'volatile' pointer
qualifiers into the pointer record, as well as adding support for
'__restrict' qualifiers in the same place.
Based on a patch from Aaron Smith
Differential Revision: https://reviews.llvm.org/D43060
llvm-svn: 326260
Based on a profile, a couple of hot spots were identified in the
main type merging loop. The code was simplified, a few loops
were re-arranged, and some outlined functions were inlined. This
speeds up type merging by a decent amount, shaving around 3-4 seconds
off of a 40 second link in my test case.
Differential Revision: https://reviews.llvm.org/D42559
llvm-svn: 323790
There's some abstraction overhead in the underlying
mechanisms that were being used, and it was leading to an
abundance of small but not-free copies being made. This
showed up on a profile. Eliminating this and going back to
a low-level byte-based implementation speeds up lld with
/DEBUG between 10 and 15%.
Differential Revision: https://reviews.llvm.org/D42148
llvm-svn: 322871
This adds the /DEBUG:GHASH option to LLD which will look for
the existence of .debug$H sections in linker inputs and use them
to accelerate type merging. The clang-cl side has already been
added, so this completes the work necessary to begin experimenting
with this feature.
Differential Revision: https://reviews.llvm.org/D40980
llvm-svn: 320719
Currently this is an LLVM extension to the COFF spec which is
experimental and intended to speed up linking. For now it is
behind a hidden cl::opt flag, but in the future we can move it
to a "real" cc1 flag and have the driver pass it through whenever
it is appropriate.
The patch to actually make use of this section in lld will come
in a followup.
Differential Revision: https://reviews.llvm.org/D40917
llvm-svn: 320649
Previously, when linking against libcmt from the MSVC runtime,
lld-link /verbose would show "Ignoring unknown symbol record
with kind 0x1006". It turns out this was because
TypeIndexDiscovery did not handle S_REGISTER records, so these
records were not getting properly remapped.
Patch by: Alexnadre Ganea
Differential Revision: https://reviews.llvm.org/D40919
llvm-svn: 320108
Currently nothing uses this, but this at least gets the core
algorithm in, and adds some test to demonstrate correctness.
Differential Revision: https://reviews.llvm.org/D40736
llvm-svn: 319854
This was storing the hash alongside the key so that the hash
doesn't need to be re-computed every time, but in doing so it
was allocating a structure to keep the key size small in the
DenseMap. This is a noble goal, but it also leads to a pointer
indirection on every probe, and this cost of this pointer
indirection ends up being higher than the cost of having a
slightly larger entry in the hash table. Removing this not only
simplifies the code, but yields a small but noticeable
performance improvement in the type merging algorithm.
llvm-svn: 319493
This class had some code that would automatically remap type
indices before hashing and serializing. The only caller of
this method was the TypeStreamMerger anyway, and the method
doesn't make general sense, and prevents making certain future
improvements to the class. So, factoring this up one level
into the TypeStreamMerger where it belongs.
llvm-svn: 319377
A couple of places in LLD were passing references to
TypeTableCollections around, which makes it hard to change the
implementation at runtime. However, these cases only needed to
iterate over the types in the collection, and TypeCollection
already provides a handy abstract interface for this purpose.
By implementing this interface, we can get rid of the need to
pass TypeTableBuilder references around, which should allow us
to swap the implementation at runtime in subsequent patches.
llvm-svn: 319345
The motivation behind this patch is that future directions require us to
be able to compute the hash value of records independently of actually
using them for de-duplication.
The current structure of TypeSerializer / TypeTableBuilder being a
single entry point that takes an unserialized type record, and then
hashes and de-duplicates it is not flexible enough to allow this.
At the same time, the existing TypeSerializer is already extremely
complex for this very reason -- it tries to be too many things. In
addition to serializing, hashing, and de-duplicating, ti also supports
splitting up field list records and adding continuations. All of this
functionality crammed into this one class makes it very complicated to
work with and hard to maintain.
To solve all of these problems, I've re-written everything from scratch
and split the functionality into separate pieces that can easily be
reused. The end result is that one class TypeSerializer is turned into 3
new classes SimpleTypeSerializer, ContinuationRecordBuilder, and
TypeTableBuilder, each of which in isolation is simple and
straightforward.
A quick summary of these new classes and their responsibilities are:
- SimpleTypeSerializer : Turns a non-FieldList leaf type into a series of
bytes. Does not do any hashing. Every time you call it, it will
re-serialize and return bytes again. The same instance can be re-used
over and over to avoid re-allocations, and in exchange for this
optimization the bytes returned by the serializer only live until the
caller attempts to serialize a new record.
- ContinuationRecordBuilder : Turns a FieldList-like record into a series
of fragments. Does not do any hashing. Like SimpleTypeSerializer,
returns references to privately owned bytes, so the storage is
invalidated as soon as the caller tries to re-use the instance. Works
equally well for LF_FIELDLIST as it does for LF_METHODLIST, solving a
long-standing theoretical limitation of the previous implementation.
- TypeTableBuilder : Accepts sequences of bytes that the user has already
serialized, and inserts them by de-duplicating with a hash table. For
the sake of convenience and efficiency, this class internally stores a
SimpleTypeSerializer so that it can accept unserialized records. The
same is not true of ContinuationRecordBuilder. The user is required to
create their own instance of ContinuationRecordBuilder.
Differential Revision: https://reviews.llvm.org/D40518
llvm-svn: 319198
The type index is from the TPI stream, not the IPI stream. Fix the
dumper, fix type index discovery, and add a test in LLD.
Also improve the log message we emit when we fail to rewrite type
indices in LLD. That's how I found this bug.
llvm-svn: 316461
Alexandre Ganea