This prevents the linker from trying to emit relative relocations to locally-defined public symbols into dynamic libraries, which gives ld.so heartache.
This is the first patch in a series that will allow new protocol
requirements to be added resiliently, with the runtime filling in
default implementations in witness tables.
First, this adds a new flag to the protocol descriptor indicating
that the protocol is resilient. In this case, there are two
additional fields, MinimumWitnessTableSizeInWords and
DefaultWitnessTableSizeInWords, followed by tail-allocated
default witnesses.
The swift_getGenericWitnessTable() entry point now fills in the
default witnesses from the protocol if the given witness table
template is smaller than the expected witness table size.
This also changes the layout of instantiated witness tables to move
the address point to the end of private data. Previously the private
data came after the requirements, but this meant that adding new
requirements would require sliding the private data at runtime and
accessing it indirectly. It is much simpler to access it from
negative offsets instead.
I updated IRGen to emit the new metadata, but currently all protocols
are flagged as not resilient, and default witnesses are not emitted;
this will come in a subsequent patch once some more plumbing is
in place.
To avoid generating GOT entries for references to protocols defined
in the current module, I had to add some hacks to the existing hack
for this. I'll hopefully clean this up in a principled manner later.
of associated types in protocol witness tables.
We use the global access functions when the result isn't
dependent, and a simple accessor when the result can be cheaply
recovered from the conforming metadata. Otherwise, we add a
cache slot to a private section of the witness table, forcing
an instantiation per conformance. Like generic type metadata,
concrete instantiations of generic conformances are memoized.
There's a fair amount of code in this patch that can't be
dynamically tested at the moment because of the widespread
reliance on recursive expansion of archetypes / dependent
types. That's something we're now theoretically in a position
to change, and as we do so, we'll test more of this code.
This speculatively re-applies 7576a91009,
i.e. reverts commit 11ab3d537f.
We have not been able to duplicate the build failure in
independent testing; it might have been spurious or unrelated.
of associated types in protocol witness tables.
We use the global access functions when the result isn't
dependent, and a simple accessor when the result can be cheaply
recovered from the conforming metadata. Otherwise, we add a
cache slot to a private section of the witness table, forcing
an instantiation per conformance. Like generic type metadata,
concrete instantiations of generic conformances are memoized.
There's a fair amount of code in this patch that can't be
dynamically tested at the moment because of the widespread
reliance on recursive expansion of archetypes / dependent
types. That's something we're now theoretically in a position
to change, and as we do so, we'll test more of this code.
This reverts commit 6528ec2887, i.e.
it reapplies b1e3120a28, with a fix
to unbreak release builds.
This reverts commit b1e3120a28.
Reverting because this patch uses WitnessTableBuilder::PI in NDEBUG code.
That field only exists when NDEBUG is not defined, but now NextCacheIndex, a
field that exists regardless, is being updated based on information from PI.
This problem means that Release builds do not work.
of associated types in protocol witness tables.
We use the global access functions when the result isn't
dependent, and a simple accessor when the result can be cheaply
recovered from the conforming metadata. Otherwise, we add a
cache slot to a private section of the witness table, forcing
an instantiation per conformance. Like generic type metadata,
concrete instantiations of generic conformances are memoized.
There's a fair amount of code in this patch that can't be
dynamically tested at the moment because of the widespread
reliance on recursive expansion of archetypes / dependent
types. That's something we're now theoretically in a position
to change, and as we do so, we'll test more of this code.
By using relative references, either directly to symbols internal to the current TU, or to the GOT entry for external symbols, we avoid unnecessary runtime relocations, and we save space on 64-bit platforms, since a single image is still <2GB in size. For the 64-bit standard library, this trades 26KB of fake-const data in __DATA,__swift1_proto for 13KB of true-const data in __TEXT,__swift2_proto. Implements rdar://problem/22334380.
Swift SVN r31555
This is more resilient, since we want to be able to add more information behind the address point of type objects. The start of the metadata object is now an internal "full metadata" symbol.
Note that we can't do this for known opaque metadata from the C++ runtime, since clang doesn't have a good way to emit offset symbol aliases, so for non-nominal metadata objects we still emit an adjustment inline. We also aren't able to generate references to aliases within the same module due to an MC bug with alias refs on i386 and armv7 (rdar://problem/22450593).
Swift SVN r31523
This is more resilient, since we want to be able to add more information behind the address point of type objects, and also makes IR a lot less cluttered. The start of the metadata object is now an internal "full metadata" symbol.
Note that we can't do this for known opaque metadata from the C++ runtime, since clang doesn't have a good way to emit offset symbol aliases, so for non-nominal metadata objects we still emit an adjustment inline.
Swift SVN r31515
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
Update SILGen to create SILGlobalVariable and SILGlobalAddrInst instead of
GlobalAddrInst. When we see a definition for a global variable, we create
the corrsponding SILGlobalVariable definition.
When creating SILGlobalVariable from a global VarDecl, we mangle the global
VarDecl in the same way as we mangle it at IRGen. The SILLinkage is also
set in the same way as we set it at IRGen.
At IRGen, we use the associated VarDecl for SILGlobalVariable if it exists,
to have better debugging information.
We set the initializer for SILGlobalVariable definition only.
We also handle SILGlobalAddrInst in various SILPasses, in the similar way
as we handle GlobalAddrInst.
rdar://15493694
Swift SVN r21887
...so that they don't get dead-stripped out of an executable...
...so that they can be accessed by unit tests (or in-process plug-ins).
In Swift, marking something 'public' is a deliberate action (unlike in C),
so anything marked 'public' should be left in the final binary...even when
we're building an executable.
We currently /also/ mark the symbols for internal and private decls as
external as well, so they also won't be stripped. Hopefully that will
change soon.
rdar://problem/18173029
Swift SVN r21815
This is a simple, trivialy, not-even-half-way-there solution to weak
leaking of Objective-C classes introduced after the deployment
target. It only works for Objective-C classes and C global variables
that Clang consideres to be "weak imported". However, this bare
minimum should be enough to develop an app (by jumping through various
hoops) that uses new functionality when its
available. <rdar://problem/17296490>, which I've restricted in scope
to capture this.
Swift SVN r20956
functions, and make those functions memoize the result.
This memoization can be both threadsafe and extremely
fast because of the memory ordering rules of the platforms
we're targeting: x86 is very permissive, and ARM has a
very convenient address-dependence rule which happens to
exactly match the semantics we need.
Swift SVN r20381
Teach IRGen to honor the linkage of SILWitnessTables, and teach SILGen to emit witness tables and protocol witness thunks for external definitions with shared linkage. Fixes <rdar://problem/16264703>.
Swift SVN r14908
We should also remove it from IRGen's Explosion API; IRGen
should always use maximal explosion, and SILGen will tell us
whether or not we need to put that in memory somewhere.
But that can be a later commit.
Swift SVN r14242
We're mostly not that bad about this right now, but lazy
emission is going to wreak havoc.
Note that SILGen itself doesn't really make very good decisions
about the order in which to emit functions, but step one
towards fixing that is actually respecting it.
Swift SVN r14200
It was convenient to just assume that the SILModule defines
the deallocating destructor function. This should probably
be represented somehow in e.g. the sil_vtable instead of
being an implicit dependency.
Swift SVN r12412
Note that this lowering currently assumes that the static type of the class is its dynamic type. This should be a flag on the dealloc_ref instruction, not an assumption.
Swift SVN r12144
In general, this forces SILGen and IRGen code that's grabbing
a declaration to state whether it's doing so to define it.
Change SIL serialization to serialize the linkage of functions
and global variables, which means also serializing declarations.
Change the deserializer to use this stored linkage, even when
only deserializing a declaration, and to call a callback to
inform the client that it has deserialized a new entity.
Take advantage of that callback in the linking pass to alter
the deserialized linkage as appropriate for the fact that we
imported the declaration. This computation should really take
advantage of the relationship between modules, but currently
it does not.
Swift SVN r12090
SILGen eagerly produces witness tables for all of the conformances defined in the module, which is what we want in order to make them runtime-unique. Have IRGen follow suit. This should address a ton of radars about breakage with non-unique conformances once SIL witnesses are turned on. We will need some runtime machinery to handle witness tables with dependent fields, but since we currently ignore the associated type fields of witnesses, we can get away with emitting direct references to all witness tables for now.
Swift SVN r11608
Produce protocol descriptors when we see a protocol definition in the current module. If the protocol is @objc, go through the existing path for generating full Protocol* metadata for objc objects; otherwise, emit our layout-compatible but strong-external-linkage Swift protocol descriptor record.
Swift SVN r9867
Build a nominal type descriptor when we emit the metadata or generic metadata pattern for a nominal type, and put a reference into the formerly null slot in the struct or enum metadata. We need to make a place for them in class metadata; that'll come next.
Swift SVN r9492
Add a SILLinkage mode "Deserialized" to make sure IRGen will emit
hidden symbols for deserialized SILFunction.
Inside SIL linker, set Linkage to external if we only have a declaration for
a callee function.
Both sil block and decl block in a module can emit an array of substitutions.
To share the serialization between SILSerializer and Serializer, we modify
the interface to pass in the abbreviation codes to write functions and to
pass in a cursor to read functions.
We now correctly handle the serialization of Substitutions in SpecializeInst.
For a deserialized SILFunction, we now temporarily set its SILLocation and
DebugScope to an empty FileLocation. Once mandatory inliner sets the SILLocation
to the location of ApplyInst, a null SILLocation and a null DebugScope
may work for a deserialized SILFunction.
Update testing cases to reflect that we are now inlining transparent functions
from modules, or to disable SILDeserializer for now (I am not sure how to update
those testing cases).
Swift SVN r8582
Lazily-generated currying thunks will require the same IR-level linkonce_odr linkage as clang thunks currently do, so generalize the name of the existing SIL-level linkage specifier 'clang_thunk'.
Swift SVN r8122
Among other things this enables mangled names for tuples.
This adds a pointer to the DeclContext to SILFunction and which is used
to provide the necessary context to the Mangler.
Fixes rdar://problem/14808764 and rdar://problem/14813658.
Swift SVN r8070
