This patch intended to provide additional interface to LLVMsymbolizer
such that they work directly on object files. There is an existing
method - symbolizecode which takes an object file, this patch provides
similar overloads for symbolizeInlinedCode, symbolizeData,
symbolizeFrame. This can be useful for clients who already have a
in-memory object files to symbolize for.
Patch By: pvellien (praveen velliengiri)
Reviewed By: scott.linder
Differential Revision: https://reviews.llvm.org/D95232
Current dsymutil implementation of hasLiveMemoryLocation()/hasLiveAddressRange()
and applyValidRelocs() assume that calls should be done in certain order
(from first Dies to last). Multi-thread implementation might call these methods
in other order(it might process compilation units in order other than they are physically
located), so we remove restriction that searching for relocations should be done
in ascending order. This change does not introduce noticable performance degradation.
The testing results for clang binary:
golden-dsymutil/dsymutil 23787992
clang MD5: 5efa8fd9355ebf81b65f24db5375caa2
elapsed time=91sec
build-Release/bin/dsymutil 23855616
clang MD5: 5efa8fd9355ebf81b65f24db5375caa2
elapsed time=91sec
Differential Revision: https://reviews.llvm.org/D93106
This patch adds the ability to evaluate the state machine for CIE and FDE unwind objects and produce a UnwindTable with all UnwindRow objects needed to unwind registers. It will also dump the UnwindTable for each CIE and FDE when dumping DWARF .debug_frame or .eh_frame sections in llvm-dwarfdump or llvm-objdump. This allows users to see what the unwind rows actually look like for a given CIE or FDE instead of just seeing a list of opcodes.
This patch adds new classes: UnwindLocation, RegisterLocations, UnwindRow, and UnwindTable.
UnwindLocation is a class that describes how to unwind a register or Call Frame Address (CFA).
RegisterLocations is a class that tracks registers and their UnwindLocations. It gets populated when parsing the DWARF call frame instruction opcodes for a unwind row. The registers are mapped from their register numbers to the UnwindLocation in a map.
UnwindRow contains the result of evaluating a row of DWARF call frame instructions for the CIE, or a row from a FDE. The CIE can produce a set of initial instructions that each FDE that points to that CIE will use as the seed for the state machine when parsing FDE opcodes. A UnwindRow for a CIE will not have a valid address, whille a UnwindRow for a FDE will have a valid address.
The UnwindTable is a class that contains a sorted (by address) vector of UnwindRow objects and is the result of parsing all opcodes in a CIE, or FDE. Parsing a CIE should produce a UnwindTable with a single row. Parsing a FDE will produce a UnwindTable with one or more UnwindRow objects where all UnwindRow objects have valid addresses. The rows in the UnwindTable will be sorted from lowest Address to highest after parsing the state machine, or an error will be returned if the table isn't sorted. To parse a UnwindTable clients can use the following methods:
static Expected<UnwindTable> UnwindTable::create(const CIE *Cie);
static Expected<UnwindTable> UnwindTable::create(const FDE *Fde);
A valid table will be returned if the DWARF call frame instruction opcodes have no encoding errors. There are a few things that can go wrong during the evaluation of the state machine and these create functions will catch and return them.
Differential Revision: https://reviews.llvm.org/D89845
NativeEnumInjectedSources.h needs PDBFile but relies on a
forward declaration of PDBFile in InjectedSourceStream.h.
This patch adds a forward declaration right in
NativeEnumInjectedSources.h.
While we are at it, this patch removes the one in
InjectedSourceStream.h, where it is unnecessary.
This reverts commit 5b7aef6eb4b2930971029b984cb2360f7682e5a5 and relands
6529d7c5a45b1b9588e512013b02f891d71bc134.
The ASan error was debugged and determined to be the fault of an invalid
object file input in our test suite, which was fixed by my last change.
LLD's project policy is that it assumes input objects are valid, so I
have added a comment about this assumption to the relocation bounds
check.
This is a pretty classic optimization. Instead of processing symbol
records and copying them to temporary storage, do a first pass to
measure how large the module symbol stream will be, and then copy the
data into place in the PDB file. This requires defering relocation until
much later, which accounts for most of the complexity in this patch.
This patch avoids copying the contents of all live .debug$S sections
into heap memory, which is worth about 20% of private memory usage when
making PDBs. However, this is not an unmitigated performance win,
because it can be faster to read dense, temporary, heap data than it is
to iterate symbol records in object file backed memory a second time.
Results on release chrome.dll:
peak mem: 5164.89MB -> 4072.19MB (-1,092.7MB, -21.2%)
wall-j1: 0m30.844s -> 0m32.094s (slightly slower)
wall-j3: 0m20.968s -> 0m20.312s (slightly faster)
wall-j8: 0m19.062s -> 0m17.672s (meaningfully faster)
I gathered similar numbers for a debug, component build of content.dll
in Chrome, and the performance impact of this change was in the noise.
The memory usage reduction was visible and similar.
Because of the new parallelism in the PDB commit phase, more cores makes
the new approach faster. I'm assuming that most C++ developer machines
these days are at least quad core, so I think this is a win.
Differential Revision: https://reviews.llvm.org/D94267
Part of the <=> changes in C++20 make certain patterns of writing equality
operators ambiguous with themselves (sorry!).
This patch goes through and adjusts all the comparison operators such that
they should work in both C++17 and C++20 modes. It also makes two other small
C++20-specific changes (adding a constructor to a type that cases to be an
aggregate, and adding casts from u8 literals which no longer have type
const char*).
There were four categories of errors that this review fixes.
Here are canonical examples of them, ordered from most to least common:
// 1) Missing const
namespace missing_const {
struct A {
#ifndef FIXED
bool operator==(A const&);
#else
bool operator==(A const&) const;
#endif
};
bool a = A{} == A{}; // error
}
// 2) Type mismatch on CRTP
namespace crtp_mismatch {
template <typename Derived>
struct Base {
#ifndef FIXED
bool operator==(Derived const&) const;
#else
// in one case changed to taking Base const&
friend bool operator==(Derived const&, Derived const&);
#endif
};
struct D : Base<D> { };
bool b = D{} == D{}; // error
}
// 3) iterator/const_iterator with only mixed comparison
namespace iter_const_iter {
template <bool Const>
struct iterator {
using const_iterator = iterator<true>;
iterator();
template <bool B, std::enable_if_t<(Const && !B), int> = 0>
iterator(iterator<B> const&);
#ifndef FIXED
bool operator==(const_iterator const&) const;
#else
friend bool operator==(iterator const&, iterator const&);
#endif
};
bool c = iterator<false>{} == iterator<false>{} // error
|| iterator<false>{} == iterator<true>{}
|| iterator<true>{} == iterator<false>{}
|| iterator<true>{} == iterator<true>{};
}
// 4) Same-type comparison but only have mixed-type operator
namespace ambiguous_choice {
enum Color { Red };
struct C {
C();
C(Color);
operator Color() const;
bool operator==(Color) const;
friend bool operator==(C, C);
};
bool c = C{} == C{}; // error
bool d = C{} == Red;
}
Differential revision: https://reviews.llvm.org/D78938
Revert "Delete llvm::is_trivially_copyable and CMake variable HAVE_STD_IS_TRIVIALLY_COPYABLE"
This reverts commit 4d4bd40b578d77b8c5bc349ded405fb58c333c78.
This reverts commit 557b00e0afb2dc1776f50948094ca8cc62d97be4.
llvm-symbolizer used to use the DIA SDK for symbolization on
Windows; this patch switches to using native symbolization, which was
implemented recently.
Users can still make the symbolizer use DIA by adding the `-dia` flag
in the LLVM_SYMBOLIZER_OPTS environment variable.
Differential Revision: https://reviews.llvm.org/D91814
Seems users have enough different uses of the symbolizer where they
might have unknown binaries and offsets such that "best effort" behavior
is all that's expected of llvm-symbolizer - so even erroring on unknown
executables and out of bounds offsets might not be suitable.
This reverts commit 1de0199748ef2a20cd146c100ea1b8e6726c4767.
This reverts commit a7b209a6d40d77b43a38664b1fe64513587f24c6.
This reverts commit 338dd138ea4a70b52ab48e0c8aa38ec152b3569a.
Create the LLVM / CodeView register mappings for the 32-bit ARM Window targets.
Reviewed By: compnerd
Differential Revision: https://reviews.llvm.org/D89622
There's no way to know whether there's a loclist contribution to parse
if there's no loclistx encoding - and if there is one, there's no need
to walk back from the loclist_base (or, uin the case of
info.dwo/loclist.dwo - starting at 0 in the contribution) to parse the
header, instead rely on the DWARF32/64 and address size in the CU
that's already available.
This would come up in split DWARF (non-split wouldn't try to read a
loclist header in the absence of a loclist_base) when one unit had
location lists and another does not (because the loclists.dwo section
would be non-empty in that case - in the case where it's empty the
parsing would silently skip).
Simplify the testing a bit, rather than needing a whole dwp, etc - by
creating a malformed loclists.dwo section (and use single file Split
DWARF) that would trip up any attempt to parse it - but no attempt
should be made.
It's not possible to do this in complete generality - a CU using a
sec_offset DW_AT_ranges has no way of knowing where its rnglists
contribution starts, so should not attempt to parse any full rnglist
table/header to do so. And even using FORM_rnglistx there's no need to
parse the header - the offset can be computed using the CU's DWARF
format (32 or 64) to compute offset entry sizes, and then the list
parsed at that offset without ever trying to find a rnglist contribution
header immediately prior to the rnglists_base.
Stored Error objects have to be checked, even if they are success
values.
This reverts commit 8d250ac3cd48d0f17f9314685a85e77895c05351.
Relands commit 49b3459930655d879b2dc190ff8fe11c38a8be5f..
Original commit message:
-----------------------------------------
This makes type merging much faster (-24% on chrome.dll) when multiple
threads are available, but it slightly increases the time to link (+10%)
when /threads:1 is passed. With only one more thread, the new type
merging is faster (-11%). The output PDB should be identical to what it
was before this change.
To give an idea, here is the /time output placed side by side:
BEFORE | AFTER
Input File Reading: 956 ms | 968 ms
Code Layout: 258 ms | 190 ms
Commit Output File: 6 ms | 7 ms
PDB Emission (Cumulative): 6691 ms | 4253 ms
Add Objects: 4341 ms | 2927 ms
Type Merging: 2814 ms | 1269 ms -55%!
Symbol Merging: 1509 ms | 1645 ms
Publics Stream Layout: 111 ms | 112 ms
TPI Stream Layout: 764 ms | 26 ms trivial
Commit to Disk: 1322 ms | 1036 ms -300ms
----------------------------------------- --------
Total Link Time: 8416 ms 5882 ms -30% overall
The main source of the additional overhead in the single-threaded case
is the need to iterate all .debug$T sections up front to check which
type records should go in the IPI stream. See fillIsItemIndexFromDebugT.
With changes to the .debug$H section, we could pre-calculate this info
and eliminate the need to do this walk up front. That should restore
single-threaded performance back to what it was before this change.
This change will cause LLD to be much more parallel than it used to, and
for users who do multiple links in parallel, it could regress
performance. However, when the user is only doing one link, it's a huge
improvement. In the future, we can use NT worker threads to avoid
oversaturating the machine with work, but for now, this is such an
improvement for the single-link use case that I think we should land
this as is.
Algorithm
----------
Before this change, we essentially used a
DenseMap<GloballyHashedType, TypeIndex> to check if a type has already
been seen, and if it hasn't been seen, insert it now and use the next
available type index for it in the destination type stream. DenseMap
does not support concurrent insertion, and even if it did, the linker
must be deterministic: it cannot produce different PDBs by using
different numbers of threads. The output type stream must be in the same
order regardless of the order of hash table insertions.
In order to create a hash table that supports concurrent insertion, the
table cells must be small enough that they can be updated atomically.
The algorithm I used for updating the table using linear probing is
described in this paper, "Concurrent Hash Tables: Fast and General(?)!":
https://dl.acm.org/doi/10.1145/3309206
The GHashCell in this change is essentially a pair of 32-bit integer
indices: <sourceIndex, typeIndex>. The sourceIndex is the index of the
TpiSource object, and it represents an input type stream. The typeIndex
is the index of the type in the stream. Together, we have something like
a ragged 2D array of ghashes, which can be looked up as:
tpiSources[tpiSrcIndex]->ghashes[typeIndex]
By using these side tables, we can omit the key data from the hash
table, and keep the table cell small. There is a cost to this: resolving
hash table collisions requires many more loads than simply looking at
the key in the same cache line as the insertion position. However, most
supported platforms should have a 64-bit CAS operation to update the
cell atomically.
To make the result of concurrent insertion deterministic, the cell
payloads must have a priority function. Defining one is pretty
straightforward: compare the two 32-bit numbers as a combined 64-bit
number. This means that types coming from inputs earlier on the command
line have a higher priority and are more likely to appear earlier in the
final PDB type stream than types from an input appearing later on the
link line.
After table insertion, the non-empty cells in the table can be copied
out of the main table and sorted by priority to determine the ordering
of the final type index stream. At this point, item and type records
must be separated, either by sorting or by splitting into two arrays,
and I chose sorting. This is why the GHashCell must contain the isItem
bit.
Once the final PDB TPI stream ordering is known, we need to compute a
mapping from source type index to PDB type index. To avoid starting over
from scratch and looking up every type again by its ghash, we save the
insertion position of every hash table insertion during the first
insertion phase. Because the table does not support rehashing, the
insertion position is stable. Using the array of insertion positions
indexed by source type index, we can replace the source type indices in
the ghash table cells with the PDB type indices.
Once the table cells have been updated to contain PDB type indices, the
mapping for each type source can be computed in parallel. Simply iterate
the list of cell positions and replace them with the PDB type index,
since the insertion positions are no longer needed.
Once we have a source to destination type index mapping for every type
source, there are no more data dependencies. We know which type records
are "unique" (not duplicates), and what their final type indices will
be. We can do the remapping in parallel, and accumulate type sizes and
type hashes in parallel by type source.
Lastly, TPI stream layout must be done serially. Accumulate all the type
records, sizes, and hashes, and add them to the PDB.
Differential Revision: https://reviews.llvm.org/D87805
This makes type merging much faster (-24% on chrome.dll) when multiple
threads are available, but it slightly increases the time to link (+10%)
when /threads:1 is passed. With only one more thread, the new type
merging is faster (-11%). The output PDB should be identical to what it
was before this change.
To give an idea, here is the /time output placed side by side:
BEFORE | AFTER
Input File Reading: 956 ms | 968 ms
Code Layout: 258 ms | 190 ms
Commit Output File: 6 ms | 7 ms
PDB Emission (Cumulative): 6691 ms | 4253 ms
Add Objects: 4341 ms | 2927 ms
Type Merging: 2814 ms | 1269 ms -55%!
Symbol Merging: 1509 ms | 1645 ms
Publics Stream Layout: 111 ms | 112 ms
TPI Stream Layout: 764 ms | 26 ms trivial
Commit to Disk: 1322 ms | 1036 ms -300ms
----------------------------------------- --------
Total Link Time: 8416 ms 5882 ms -30% overall
The main source of the additional overhead in the single-threaded case
is the need to iterate all .debug$T sections up front to check which
type records should go in the IPI stream. See fillIsItemIndexFromDebugT.
With changes to the .debug$H section, we could pre-calculate this info
and eliminate the need to do this walk up front. That should restore
single-threaded performance back to what it was before this change.
This change will cause LLD to be much more parallel than it used to, and
for users who do multiple links in parallel, it could regress
performance. However, when the user is only doing one link, it's a huge
improvement. In the future, we can use NT worker threads to avoid
oversaturating the machine with work, but for now, this is such an
improvement for the single-link use case that I think we should land
this as is.
Algorithm
----------
Before this change, we essentially used a
DenseMap<GloballyHashedType, TypeIndex> to check if a type has already
been seen, and if it hasn't been seen, insert it now and use the next
available type index for it in the destination type stream. DenseMap
does not support concurrent insertion, and even if it did, the linker
must be deterministic: it cannot produce different PDBs by using
different numbers of threads. The output type stream must be in the same
order regardless of the order of hash table insertions.
In order to create a hash table that supports concurrent insertion, the
table cells must be small enough that they can be updated atomically.
The algorithm I used for updating the table using linear probing is
described in this paper, "Concurrent Hash Tables: Fast and General(?)!":
https://dl.acm.org/doi/10.1145/3309206
The GHashCell in this change is essentially a pair of 32-bit integer
indices: <sourceIndex, typeIndex>. The sourceIndex is the index of the
TpiSource object, and it represents an input type stream. The typeIndex
is the index of the type in the stream. Together, we have something like
a ragged 2D array of ghashes, which can be looked up as:
tpiSources[tpiSrcIndex]->ghashes[typeIndex]
By using these side tables, we can omit the key data from the hash
table, and keep the table cell small. There is a cost to this: resolving
hash table collisions requires many more loads than simply looking at
the key in the same cache line as the insertion position. However, most
supported platforms should have a 64-bit CAS operation to update the
cell atomically.
To make the result of concurrent insertion deterministic, the cell
payloads must have a priority function. Defining one is pretty
straightforward: compare the two 32-bit numbers as a combined 64-bit
number. This means that types coming from inputs earlier on the command
line have a higher priority and are more likely to appear earlier in the
final PDB type stream than types from an input appearing later on the
link line.
After table insertion, the non-empty cells in the table can be copied
out of the main table and sorted by priority to determine the ordering
of the final type index stream. At this point, item and type records
must be separated, either by sorting or by splitting into two arrays,
and I chose sorting. This is why the GHashCell must contain the isItem
bit.
Once the final PDB TPI stream ordering is known, we need to compute a
mapping from source type index to PDB type index. To avoid starting over
from scratch and looking up every type again by its ghash, we save the
insertion position of every hash table insertion during the first
insertion phase. Because the table does not support rehashing, the
insertion position is stable. Using the array of insertion positions
indexed by source type index, we can replace the source type indices in
the ghash table cells with the PDB type indices.
Once the table cells have been updated to contain PDB type indices, the
mapping for each type source can be computed in parallel. Simply iterate
the list of cell positions and replace them with the PDB type index,
since the insertion positions are no longer needed.
Once we have a source to destination type index mapping for every type
source, there are no more data dependencies. We know which type records
are "unique" (not duplicates), and what their final type indices will
be. We can do the remapping in parallel, and accumulate type sizes and
type hashes in parallel by type source.
Lastly, TPI stream layout must be done serially. Accumulate all the type
records, sizes, and hashes, and add them to the PDB.
Differential Revision: https://reviews.llvm.org/D87805
Since DWARFv5 places TUs in debug_info, some of DWARFContext's APIs have
become a bit erroneous, including TUs in the CU list by accident.
Correct that by providing compile_units (& dwo_compile_units) that
filter out the type units from the debug_info units.
Differential Revision: https://reviews.llvm.org/D87935
This matches the debug_ranges behavior - though is currently implemented
differently. (the debug_ranges parsing was handled by creating a new
ranges parser during DIE address querying, and just destroying it after
the query - whereas the rnglists parser is a member of the DWARFUnit
currently - so the API doesn't cache anymore)
I think this could/should be improved by not parsing debug_rnglists
headers at all when dumping debug_info or symbolizing - do it the way
DWARF (roughly) intended: take the rnglists_base, add addr*index to it,
read the offset, parse the list at rnglists_base+offset. This would have
no error checking for valid index (because the number of valid indexes
is stored in the header, which has a negative offset from rnglists_base
- and is sort of only intended for use by dumpers, not by parsers going
from debug_info to a rnglist) or out of contribution bounds access
(since it wouldn't know the length of the contribution, also in the
header) - nor any error-checking that the rnglist contribution was using
the same properties as the debug_info (version, DWARF32/64, address
size, etc).
Most clients only need CVType and CVSymbol, not structs for every type
and symbol. Move CVSymbol and CVType to CVRecord.h to accomplish this.
Update some of the common headers that need CVSymbol and CVType to use
the new location.
This patch adds support for dumping the .debug_addr(v5) section to
obj2yaml.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D87601
Since a function might have portions of its code coming from multiple
different files, "start line" is ambiguous (it can't just be resolved
relative to the file/line specified). Add start file to disambiguate it.
Parsing DWARFv5 debug_loclist offsets when a CU is parsed is weighing
down memory usage of symbolizers that don't need to parse this data at
all. There's not much benefit to caching these anyway - since they are
O(1) lookup and reading once you know where the offset list starts (and
can do bounds checking with the offset list size too).
In general, I think it might be time to start paying down some of the
technical debt of loc/loclist/range/rnglist parsing to try to unify it a
bit more.
eg:
* Currently DWARFUnit has: RangeSection, RangeSectionBase, LocSection,
LocSectionBase, LocTable, RngListTable, LoclistTableHeader (be nice if
these were all wrapped up in two variables - one for loclists, one for
rnglists)
* rnglists and loclists are handled differently (see:
LoclistTableHeader, but no RnglistTableHeader)
* maybe all these types could be less stateful - lazily parse what they
need to, even reparsing rather than caching because it doesn't seem
too expensive, for instance. (though admittedly so long as it's
constantcost/overead per compilatiton that's probably adequate)
* Maybe implementing and using a DWARFDataExtractor that can be
sub-ranged (so we could slice it up to just the single contribution) -
though maybe that's not so useful because loc/ranges need to refer to
it by absolute, not contribution-relative mechanisms
Differential Revision: https://reviews.llvm.org/D86110
Note that DWARFUnit::getAbbreviations() returns nullptr if the
abbreviations could not be read, but callers used the returned
pointer without checking.
Differential Revision: https://reviews.llvm.org/D85738
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
Although the DWARF specification states that .debug_aranges entries
can't have length zero, these can occur in the wild. There's no
particular reason to enforce this part of the spec, since functionally
they have no impact. The patch removes the error and introduces a new
warning for premature terminator entries which does not stop parsing.
This is a relanding of cb3a598c87db, adding the missing obj2yaml part
that was needed.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46805. See also
https://reviews.llvm.org/D71932 which originally introduced the error.
Reviewed by: ikudrin, dblaikie, Higuoxing
Differential Revision: https://reviews.llvm.org/D85313
Although the DWARF specification states that .debug_aranges entries
can't have length zero, these can occur in the wild. There's no
particular reason to enforce this part of the spec, since functionally
they have no impact. The patch removes the error and introduces a new
warning for premature terminator entries which does not stop parsing.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46805. See also
https://reviews.llvm.org/D71932 which originally introduced the error.
Reviewed by: ikudrin, dblaikie
Differential Revision: https://reviews.llvm.org/D85313
This reverts commit 87c5437afd273e909e0fed3389de7531d5452ea5.
The commit includes several headers in the middle of a function, which
breaks pretty much everything.
