This is PR36686.
If a user of a library is LTOed with that library we take the
opportunity to set dso_local, but we don't clear dllimport, which
creates an invalid IR.
llvm-svn: 327408
Summary:
This change fixes PR36483. The bug was originally introduced by a change
that marked non-prevailing symbols dead. This broke LowerTypeTests
handling of available_externally functions, which are non-prevailing.
LowerTypeTests uses liveness information to avoid emitting thunks for
unused functions.
Marking available_externally functions dead is incorrect, the functions
are used though the function definitions are not. This change keeps them
live, and lets the EliminateAvailableExternally/GlobalDCE passes remove
them later instead.
(Reland with a suspected fix for a unit test failure I haven't been able
to reproduce locally)
Reviewers: pcc, tejohnson
Reviewed By: tejohnson
Subscribers: grimar, mehdi_amini, inglorion, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D43690
llvm-svn: 327360
Summary:
If there's a callees metadata attached to the indirect call instruction, add CallGraphEdges to the callees mentioned in the metadata when computing FunctionSummary.
* Why this is necessary:
Consider following code example:
```
(foo.c)
static int f1(int x) {...}
static int f2(int x);
static int (*fptr)(int) = f2;
static int f2(int x) {
if (x) fptr=f1; return f1(x);
}
int foo(int x) {
(*fptr)(x); // !callees metadata of !{i32 (i32)* @f1, i32 (i32)* @f2} would be attached to this call.
}
(bar.c)
int bar(int x) {
return foo(x);
}
```
At LTO time when `foo.o` is imported into `bar.o`, function `foo` might be inlined into `bar` and PGO-guided indirect call promotion will run after that. If the profile data tells that the promotion of `@f1` or `@f2` is beneficial, the optimizer will check if the "promoted" `@f1` or `@f2` (such as `@f1.llvm.0` or `@f2.llvm.0`) is available. Without this patch, importing `!callees` metadata would only add promoted declarations of `@f1` and `@f2` to the `bar.o`, but still the optimizer will assume that the function is available and perform the promotion. The result of that is link failure with `undefined reference to @f1.llvm.0`.
This patch fixes this problem by adding callees in the `!callees` metadata to CallGraphEdges so that their definition would be properly imported into.
One may ask that there already is a logic to add indirect call promotion targets to be added to CallGraphEdges. However, if profile data says "indirect call promotion is only beneficial under a certain inline context", the logic wouldn't work. In the code example above, if profile data is like
```
bar:1000000:100000
1:100000
1: foo:100000
1: 100000 f1:100000
```
, Computing FunctionSummary for `foo.o` wouldn't add `foo->f1` to CallGraphEdges. (Also, it is at least "possible" that one can provide profile data to only link step but not to compilation step).
Reviewers: tejohnson, mehdi_amini, pcc
Reviewed By: tejohnson
Subscribers: inglorion, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D44399
llvm-svn: 327358
Summary:
This change fixes PR36483. The bug was originally introduced by a change
that marked non-prevailing symbols dead. This broke LowerTypeTests
handling of available_externally functions, which are non-prevailing.
LowerTypeTests uses liveness information to avoid emitting thunks for
unused functions.
Marking available_externally functions dead is incorrect, the functions
are used though the function definitions are not. This change keeps them
live, and lets the EliminateAvailableExternally/GlobalDCE passes remove
them later instead.
I've also enabled EliminateAvailableExternally for all optimization
levels, I believe it being disabled for O1 was an oversight.
Reviewers: pcc, tejohnson
Reviewed By: tejohnson
Subscribers: grimar, mehdi_amini, inglorion, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D43690
llvm-svn: 327041
This reverts commit 1f3bd185c53beb6aa68446974b7e80837abd6ef0 (r326107)
because it fails
ThinLTO/X86/diagnostic-handler-remarks-with-hotness.ll.
llvm-svn: 326975
This caused some links to fail with ThinLTO due to missing symbols as
well as causing some binaries to have failures at runtime. We're working
with the author to get a test case, but want to get the tree green
again.
Further, it appears to introduce a data race. While the test usage of
threads was disabled in r325361 & r325362, that isn't an acceptable fix.
I've reverted both of these as well. This code needs to be thread safe.
Test cases for this are already on the original commit thread.
llvm-svn: 326638
- thinlto_codegen_set_cache_size_bytes to control the absolute size of cache directory.
- thinlto_codegen_set_cache_size_files the size and amount of files in cache directory.
These functions have been supported in C++ LTO API for a long time, but were absent in C LTO API.
Differential Revision: https://reviews.llvm.org/D42446
llvm-svn: 326537
This wires up -pass-remarks-hotness-threshold to LTO and ThinLTO.
Next is to change the clang driver to pass this
with -fdiagnostics-hotness-threshold.
Differential Revision: https://reviews.llvm.org/D41465
llvm-svn: 326107
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.
Third attempt - moved function from lambda to static function due to build failures.
llvm-svn: 325506
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.
Second attempt, since last patch caused stage2 build to fail (now using function_ref rather than std::function).
Reverted due to buildbot failures
llvm-svn: 325454
Add GraphTraits definitions to the FunctionSummary and ModuleSummaryIndex classes. These GraphTraits will be used to construct find SCC's in ThinLTO analysis passes.
Second attempt, since last patch caused stage2 build to fail (now using function_ref rather than std::function).
llvm-svn: 325448
Summary:
TypeID summaries are used by CFI and need to be serialized by ThinLTO
indexing for later use by LTO Backend.
Reviewers: tejohnson, pcc
Subscribers: mehdi_amini, inglorion, eraman, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D42611
llvm-svn: 325182
Summary:
For symbols that has linkonce_odr linkage and unnamed_addr, it can be
auto hide by linker to avoid weak external symbols. Teach ThinLTO to
perform auto hide so it can safely promote linkonce_odr to weak symbols
without breaking this nice property.
Reviewers: tejohnson, mehdi_amini
Reviewed By: tejohnson
Subscribers: inglorion, eraman, rnk, pcc, llvm-commits
Differential Revision: https://reviews.llvm.org/D43130
llvm-svn: 324757
Summary:
Removing the dropped symbols will prevent indirect call promotion in the
ThinLTO Backend from adding a new reference to a symbol, which can
result in linker unsats. This can happen when we compile with a sample
profile collected from one binary by used for another, which may have
profiled targets that aren't used in the new binary.
Note that until dropDeadSymbols handles variables and aliases (in
progress), we may not be able to remove the declaration and can still
have an issue.
Reviewers: grimar, davidxl
Subscribers: mehdi_amini, inglorion, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D42816
llvm-svn: 324299
Summary:
This is exposed during ThinLTO compilation, when we import an alias by
creating a clone of the aliasee. Without this fix the debug type is
unnecessarily cloned and we get a duplicate, undoing the uniquing.
Fixes PR36089.
Reviewers: mehdi_amini, pcc
Subscribers: eraman, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D41669
llvm-svn: 323813
This is similar to r322317, but for visibility. It is not as neat
because we have to special case extern_weak.
The idea is the same as the previous change, make the transition to
explicit dso_local easier for the frontends. With this they only have
to add dso_local to symbols where we need some external information to
decide if it is dso_local (like it being part of an ELF executable).
llvm-svn: 322806
While updating clang tests for having clang set dso_local I noticed
that:
- There are *a lot* of tests to update.
- Many of the updates are redundant.
They are redundant because a GV is "obviously dso_local". This patch
starts formalizing that a bit by requiring that internal and private
GVs be dso_local too. Since they all are, we don't have to print
dso_local to the textual representation, making it a bit more compact
and easier to read.
llvm-svn: 322317
Summary:
With DebugTypeODRUniquing enabled, during IR linking debug metadata
in the destination module may be reached from the source module.
This means that ConstantAsMetadata nodes (e.g. on DITemplateValueParameter)
may contain a value the destination module. When trying to map such
metadata nodes, we will attempt to map a GV already in the dest module.
linkGlobalValueProto will end up with a source GV that is the same as
the dest GV as well as the new GV. Trying to access the TypeMap for the
source GV type, which is actually a dest GV type, hits an assertion
since it appears that we have mapped into the source module (because the
type is the value not a key into the map).
Detect that we don't need to access the TypeMap in this case, since
there is no need to create a bitcast from the new GV to the source GV
type as they GV are the same.
Fixes PR35722.
Reviewers: mehdi_amini, pcc
Subscribers: probinson, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D41624
llvm-svn: 322103
borked by: rL284966 (see: https://reviews.llvm.org/D25730).
Previously, Interval was unsigned (see: CachePruning.h), replacing the type with std::chrono::seconds (which is signed) causes a regression in behaviour because the c-api intends negative values to translate to large positive intervals to *effectively* disable the pruning (see comments on: setCachePruningInterval()).
Differential Revision: https://reviews.llvm.org/D41231
llvm-svn: 321077
Modify test so that it passes in the reverse-iteration bot.
We use DenseMap instead of std::map for the summaries to emit into
distributed index files. The iteration order is not defined, but
it is deterministic, which is good enough.
llvm-svn: 321000
Summary:
1. Use stream 0 only for combined module. Previously if combined module was not
processes ThinLTO used the stream for own output. However small changes in input,
could trigger combined module and shuffle outputs making life of llvm::LTO harder.
2. Always process combined module and write output to stream 0. Processing empty
combined module is cheap and allows llvm::LTO users to avoid implementing processing
which is already done in llvm::LTO.
Subscribers: mehdi_amini, inglorion, eraman, hiraditya
Differential Revision: https://reviews.llvm.org/D41267
llvm-svn: 320905
r320895 modified a test so that it needs -enable-import-metadata which
is false by default for NDEBUG, found another place that needs this
added.
llvm-svn: 320903
Summary:
This implements a missing feature to allow importing of aliases, which
was previously disabled because alias cannot be available_externally.
We instead import an alias as a copy of its aliasee.
Some additional work was required in the IndexBitcodeWriter for the
distributed build case, to ensure that the aliasee has a value id
in the distributed index file (i.e. even when it is not being
imported directly).
This is a performance win in codes that have many aliases, e.g. C++
applications that have many constructor and destructor aliases.
Reviewers: pcc
Subscribers: mehdi_amini, inglorion, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D40747
llvm-svn: 320895
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.
Originally commited as r317374, but reverted in r317395 to update some missed
tests.
Differential Revision: https://reviews.llvm.org/D35702
llvm-svn: 317408
Now that we have a way to mark GlobalValues as local we can use the symbol
resolutions that the linker plugin provides as part of lto/thinlto link
step to refine the compilers view on what symbols will end up being local.
Differential Revision: https://reviews.llvm.org/D35702
llvm-svn: 317374
Summary:
Currently the block frequency analysis is an approximation for irreducible
loops.
The new irreducible loop metadata is used to annotate the irreducible loop
headers with their header weights based on the PGO profile (currently this is
approximated to be evenly weighted) and to help improve the accuracy of the
block frequency analysis for irreducible loops.
This patch is a basic support for this.
Reviewers: davidxl
Reviewed By: davidxl
Subscribers: mehdi_amini, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D39028
llvm-svn: 317278
With r314527, promoted values get a suffix that is a decimal value of
the module hash instead of hex. Change the regex to match only decimal
suffix values.
llvm-svn: 316544
This patch adds a new kind of metadata that indicates the possible callees of
indirect calls.
Differential Revision: https://reviews.llvm.org/D37354
llvm-svn: 315944
The current code that handles personality functions when creating a
module summary does not correctly handle the case where a function's
personality function operand refers to the function indirectly
(e.g. via a bitcast). This patch handles such cases by treating
personality function references like any other reference, i.e. by
adding them to the function's reference list. This has the minor side
benefit of allowing personality functions to participate in early
dead stripping.
We do this by calling findRefEdges on the function itself. This way
we also end up handling other function operands (specifically prefix
data and prologue data) for free.
Differential Revision: https://reviews.llvm.org/D37553
llvm-svn: 312698
This change simplifies code that has to deal with
DIGlobalVariableExpression and mirrors how we treat DIExpressions in
debug info intrinsics. Before this change there were two ways of
representing empty expressions on globals, a nullptr and an empty
!DIExpression().
If someone needs to upgrade out-of-tree testcases:
perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll>
will catch 95%.
llvm-svn: 312144
This is PR33245.
Case I am fixing is next:
Imagine we have 2 BC files, one defines and uses personality routine,
second has only declaration and also uses it.
Previously algorithm computing dead symbols (llvm::computeDeadSymbols) did
not know about personality routines and leaved them dead even if function that
has routine was live.
As a result thinLTOInternalizeAndPromoteGUID() method changed binding for
such symbol to local. Later when LLD tried to link these objects it failed
because one object had undefined global symbol for routine and second
object contained local definition instead of global.
Patch set the live root flag on the corresponding FunctionSummary
for personality routines when we build the per-module summaries
during the compile step.
Differential revision: https://reviews.llvm.org/D36834
llvm-svn: 311432
Summary:
This updates the Inliner to only add a single Optimization
Remark when Inlining, rather than an Analysis Remark and an
Optimization Remark.
Fixes https://bugs.llvm.org/show_bug.cgi?id=33786
Reviewers: anemet, davidxl, chandlerc
Reviewed By: anemet
Subscribers: haicheng, fhahn, mehdi_amini, dblaikie, llvm-commits, eraman
Differential Revision: https://reviews.llvm.org/D36054
llvm-svn: 311349
Rafael Espindola