This bug would manifest itself only when a module with multiple files is being compiled and some derived classes are defined in a file different from the one where a base class is defined. Due to this bug a method from a base class would be invoked instead of a method from a derived class when devirtualization was performed. The problem was that we were saying that failure to link a vtable is equivalent to failure to find a function in the vtable itself in which case we would go up to the parent vtable.
To avoid this kind of bug in the future a test case with a module consisting of multiple files is added to the test suite.
rdar://19334105 rdar://19337398
Swift SVN r24264
The underlying problem is that e.g. even if a method is private but its class is public, the method can be referenced from another module - from the vtable of a derived class.
So far we handled this by setting the SILLinkage of such methods according to the visibility of the class. But this prevented dead method elimination.
Now I set the SILLinkage according to the visibility of the method. This enables dead method elimination, but it requires the following:
1) Still set the linkage in llvm so that it can be referenced from outside.
2) If the method is dead and eliminated, create a stub for it (which calls swift_reportMissingMethod).
Swift SVN r23889
This should have been done a long time ago since SILOptions are options that
should be able to effect everything SIL related. In this case I just want to
pass in a flag on the SILModule to enable +0 self. By putting it on the
SILModule I can conveniently check it in SILFunctionType without exposing any
internal state from SILFunctionType.cpp.
Swift SVN r23647
This allows making global addressors fragile (They use globalinit_{token,func} for initialization of globals).
It has no noticable performance impact on our benchmarks, but it removes an ugly hack which explicitly
prevented addressors from being fragile.
Swift SVN r22812
This allows making global addressors fragile (They use globalinit_{token,func} for initialization of globals).
It has no noticable performance impact on our benchmarks, but it removes an ugly hack which explicitly
prevented addressors from being fragile.
Swift SVN r22795
This is controlled by a new isWholeModule() attribute in SILModule.
It gives about 9% code size reduction on the benchmark executables.
For test-suite reasons it is currently not done for the stdlib.
Swift SVN r22491
This prevented dead function removal of inlined dead functions. Beside the stdlib it's mostly
an issue of SIL size (and therefore compiletime), because llvm did remove such functions anyway.
Swift SVN r22301
Now the SILLinkage for functions and global variables is according to the swift visibility (private, internal or public).
In addition, the fact whether a function or global variable is considered as fragile, is kept in a separate flag at SIL level.
Previously the linkage was used for this (e.g. no inlining of less visible functions to more visible functions). But it had no effect,
because everything was public anyway.
For now this isFragile-flag is set for public transparent functions and for everything if a module is compiled with -sil-serialize-all,
i.e. for the stdlib.
For details see <rdar://problem/18201785> Set SILLinkage correctly and better handling of fragile functions.
The benefits of this change are:
*) Enable to eliminate unused private and internal functions
*) It should be possible now to use private in the stdlib
*) The symbol linkage is as one would expect (previously almost all symbols were public).
More details:
Specializations from fragile functions (e.g. from the stdlib) now get linkonce_odr,default
linkage instead of linkonce_odr,hidden, i.e. they have public visibility.
The reason is: if such a function is called from another fragile function (in the same module),
then it has to be visible from a third module, in case the fragile caller is inlined but not
the specialized function.
I had to update lots of test files, because many CHECK-LABEL lines include the linkage, which has changed.
The -sil-serialize-all option is now handled at SILGen and not at the Serializer.
This means that test files in sil format which are compiled with -sil-serialize-all
must have the [fragile] attribute set for all functions and globals.
The -disable-access-control option doesn't help anymore if the accessed module is not compiled
with -sil-serialize-all, because the linker will complain about unresolved symbols.
A final note: I tried to consider all the implications of this change, but it's not a low-risk change.
If you have any comments, please let me know.
Swift SVN r22215
It is defaulted to nullptr. When it is set, we increment the SILFunction's
ref count to keep it alive.
It will be used in followon patches for globals that can be statically
initialized.
Swift SVN r21983
*NOTE* This linkage is different from {Public,Hidden}External in that it has no
extra semantic meaning beyond shared.
The use of this linkage is to ensure that we do not serialize deserialized
shared functions. Those shared functions can always be re-deserialized from the
original module. This prevents a whole class of bugs related to the
creation of module cross references since all references to the shared
item go straight to the original module.
<rdar://problem/17772847>
Swift SVN r20375
info for them and generally clean up the inline scope handling a bit.
Fix the debug scope handling for all clients of SILCloner, especially
the SIL-level spezializers and inliners.
This also adds a ton of additional assertions that will ensure that
future optimization passes won't mess with the debug info in a way that
could confuse the LLVM backend.
Swift SVN r18984
Mandatory-inlined (aka transparent functions) are still treated as if they
had the location and scope of the call site. <rdar://problem/14845844>
Support inline scopes once we have an optimizing SIL-based inliner
Patch by Adrian Prantl.
Swift SVN r18835
The deserializer holds a reference to the deserialized SILFunction, which
prevents Dead Function Elimination from erasing them.
We have a tradeoff on how often we should clean up the unused deserialized
SILFunctions. If we clean up at every optimization iteration, we may
end up deserializing the same SILFunction multiple times. For now, we clean
up only after we are done with the optimization iteration.
rdar://17046033
Swift SVN r18697
If a source file contains the main class for its module, then implicitly emit a top_level_code that invokes UIApplicationMain with the name of the marked class.
Swift SVN r18088
Pattern matching on whether or not the function was applied is fragile
in the face of various possible compositions in between the function_ref
and the apply (i.e. thin_to_thick_function as an example).
Lets be conservative and just always deserialize references to closures
during mandatory inlining when referenced via a function_ref so we avoid
this problem if additional instructions like this are added.
Swift SVN r17977
We now enforce via an assert that each witness table is unique and that
every protocol conformance that is referenceable from SIL must have a
witness table matched to it.
Also, I taught the linker that it should deserialize witness tables for
InitExistentialRefInst instructions, something that was missed before.
Swift SVN r17283
This is important since it enables one to analyze the type of the
conformance that the witness table implements which may be different
than the original type. This follows the precedent where we return the
Substitutions from the protocol conformance tree traversal.
Swift SVN r17220
When deserializing, the serialized sil loader attempts to first lookup
from its SILModule the witness table to attempt to grab a witness table
declaration. Before this patch if the SILModule could not find it, it
would attempt to deserialize it. In certain edge cases this would cause
us to attempt to deserialize a function definition which violates the
invariant that that should never happen.
This patch adds an argument to SILModule::lookUpWitnessTable that
enables you to turn off the lazy deserialization behavior. The default
argument gives the current behavior which should be used everywhere
except for the deserializer.
Swift SVN r16740
Language features like erasing concrete metatype
values are also left for the future. Still, baby steps.
The singleton ordinary metatype for existential types
is still potentially useful; we allow it to be written
as P.Protocol.
I've been somewhat cavalier in making code accept
AnyMetatypeType instead of a more specific type, and
it's likely that a number of these places can and
should be more restrictive.
When T is an existential type, parse T.Type as an
ExistentialMetatypeType instead of a MetatypeType.
An existential metatype is the formal type
\exists t:P . (t.Type)
whereas the ordinary metatype is the formal type
(\exists t:P . t).Type
which is singleton. Our inability to express that
difference was leading to an ever-increasing cascade
of hacks where information is shadily passed behind
the scenes in order to make various operations with
static members of protocols work correctly.
This patch takes the first step towards fixing that
by splitting out existential metatypes and giving
them a pointer representation. Eventually, we will
need them to be able to carry protocol witness tables
Swift SVN r15716
This enables us to get around timing issues when we create a SILModule before we
have finished loading all Swift Modules.
This manifested itself in sil-opt where we were unable to deserialize from the
standard library when optimizing a separate *.sil file.
Swift SVN r15670
I need to add in the non-lazy linking pass before I can properly test
this. But I did not want to leave this bug in the wild. Expect the test
in the next bit.
Swift SVN r15544
This patch adds in the necessary infrastructure for lazily deserializing
witness tables. This is done by following the same approach as the
deserialization/serialization of SILFunction.
Now if one calls SILModule::lookUpWitnessTable and the given witness table is a
definition, the SILModule will attempt to deserialize it from one of the other
modules.
Swift SVN r15403
