This commit adds a DebugVariable field that is shared by
- AllocBoxInst
- AllocStackInst
- DebugValueInst
- DebugValueAddrInst
Currently DebugVariable only holds the Swift argument number.
This allows us to retire several expensive heuristics in IRGen that
attempted to identify which local variables actually where arguments
and recover their relative order.
Memory footprint notes:
This commit adds a 4-byte field to 4 SILInstructin subclasses.
This was offset by 8ab1e2dd50
which removed 20 bytes from *every* SILInstruction.
Caveats:
This commit surfaces a known bug in FunctionSigantureOpts, tracked in
rdar://problem/23727705 — debug info for exploded function arguments
cannot be expressed until this is fixed.
This reapplies ed2b16dc5a with a bugfix for
generic function arrguments and an additional testcase.
<rdar://problem/21185379&22705926>
This commit adds a DebugVariable field that is shared by
- AllocBoxInst
- AllocStackInst
- DebugValueInst
- DebugValueAddrInst
Currently DebugVariable only holds the Swift argument number.
This allows us to retire several expensive heuristics in IRGen that
attempted to identify which local variables actually where arguments
and recover their relative order.
Memory footprint notes:
This commit adds a 4-byte field to 4 SILInstructin subclasses.
This was offset by 8ab1e2dd50
which removed 20 bytes from *every* SILInstruction.
Caveats:
This commit surfaces a known bug in FunctionSigantureOpts, tracked in
rdar://problem/23727705 — debug info for exploded function arguments
cannot be expressed until this is fixed.
<rdar://problem/21185379&22705926>
Handle such cases like partial applications of witness methods and applications of witness methods with substitutions.
Some of these uses-cases occur when there is a protocol defining an operator, a generic struct conforming to this protocol, and the operator conformance of this struct is expressed as a global function.
The SIL serializer can decide not to serialize the body of functions in the SIL
module, and only emit a declaration. If we keep the original linkage kind
(public, private, etc) then the deserialized module won't pass verification
because we do not allow internal functions to have external declarations. This
commit changes the linkage kind for the functions that the serializer decides to
emit as a declaration (without a body).
rdar://21989088
The drivers for this change are providing a simpler API to SIL pass
authors, having a more efficient of the in-memory representation,
and ruling out an entire class of common bugs that usually result
in hard-to-debug backend crashes.
Summary
-------
SILInstruction
Old New
+---------------+ +------------------+ +-----------------+
|SILInstruction | |SILInstruction | |SILDebugLocation |
+---------------+ +------------------+ +-----------------+
| ... | | ... | | ... |
|SILLocation | |SILDebugLocation *| -> |SILLocation |
|SILDebugScope *| +------------------+ |SILDebugScope * |
+---------------+ +-----------------+
We’re introducing a new class SILDebugLocation which represents the
combination of a SILLocation and a SILDebugScope.
Instead of storing an inline SILLocation and a SILDebugScope pointer,
SILInstruction now only has one SILDebugLocation pointer. The APIs of
SILBuilder and SILDebugLocation guarantees that every SILInstruction
has a nonempty SILDebugScope.
Developer-visible changes include:
SILBuilder
----------
In the old design SILBuilder populated the InsertedInstrs list to
allow setting the debug scopes of all built instructions in bulk
at the very end (as the responsibility of the user). In the new design,
SILBuilder now carries a "current debug scope" state and immediately
sets the debug scope when an instruction is inserted.
This fixes a use-after-free issue with with SIL passes that delete
instructions before destroying the SILBuilder that created them.
Because of this, SILBuilderWithScopes no longer needs to be a template,
which simplifies its call sites.
SILInstruction
--------------
It is neither possible or necessary to manually call setDebugScope()
on a SILInstruction any more. The function still exists as a private
method, but is only used when splicing instructions from one function
to another.
Efficiency
----------
In addition to dropping 20 bytes from each SILInstruction,
SILDebugLocations are now allocated in the SILModule's bump pointer
allocator and are uniqued by SILBuilder. Unfortunately repeat compiles
of the standard library already vary by about 5% so I couldn’t yet
produce reliable numbers for how much this saves overall.
rdar://problem/22017421
This reverts commit bf2fdb6764.
One of the build bots reported a malloc/free error, while other bots had successful builds. It could indicate a non-deterministic failure.
Preventively revert this patch as it is the most likely cause of these issues.
rdar://23611346
Use malloc/free for allocating/freeing SIL instructions instead of using the BumpPtrAllocator. This allows for memory reuse and significantly reduces the memory footprint of the compiler.
For example, a peak memory usage during a compilation of the standard library and StdlibUnitTest is reduced by 25%-30%. The performance of the compiler seems to be not affected by this change, i.e. no slowdown is measured.
The use-after-free issue reported by build bots is fixed now.
rdar://23303031
Use malloc/free for allocating/freeing SIL instructions instead of using the BumpPtrAllocator. This allows for memory reuse and significantly reduces the memory footprint of the compiler.
For example, a peak memory usage during a compilation of the standard library and StdlibUnitTest is reduced by 25%-30%. The performance of the compiler seems to be not affected by this change, i.e. no slowdown is measured.
rdar://23303031
A fixed layout type is one about which the compiler is allowed to
make certain assumptions across resilience domains. The assumptions
will be documented elsewhere, but for the purposes of this patch
series, they will include:
- the size of the type
- offsets of stored properties
- whether accessed properties are stored or computed
When -enable-resilience is passed to the frontend, all types become
resilient unless annotated with the @fixed_layout attribute.
So far, the @fixed_layout attribute only comes into play in SIL type
lowering of structs and enums, which now become address-only unless
they are @fixed_layout. For now, @fixed_layout is also allowed on
classes, but has no effect. In the future, support for less resilient
type lowering within a single resilience domain will be added, with
appropriate loads and stores in function prologs and epilogs.
Resilience is not enabled by default, which gives all types fixed
layout and matches the behavior of the compiler today. Since
we do not want the -enable-resilience flag to change the behavior
of existing compiled modules, only the currently-compiling module,
Sema adds the @fixed_layout flag to all declarations when the flag
is off. To reduce the size of .swiftmodule files, this could become
a flag on the module itself in the future.
The reasoning behind this is that the usual case is building
applications and private frameworks, where there is no need to make
anything resilient.
For the standard library, we can start out with resilience disabled,
while perfoming an audit adding @fixed_layout annotations in the
right places. Once the implementation is robust enough we can then
build the standard library with resilience enabled.
Revert "Fix complete_decl_attribute test for @fixed_layout"
Revert "Sema: non-@objc private stored properties do not need accessors"
Revert "Sema: Access stored properties of resilient structs through accessors"
Revert "Strawman @fixed_layout attribute and -{enable,disable}-resilience flags"
This reverts commit c91c6a789e.
This reverts commit 693d3d339f.
This reverts commit 085f88f616.
This reverts commit 5d99dc9bb8.
A fixed layout type is one about which the compiler is allowed to
make certain assumptions across resilience domains. The assumptions
will be documented elsewhere, but for the purposes of this patch
series, they will include:
- the size of the type
- offsets of stored properties
- whether accessed properties are stored or computed
When -enable-resilience is passed to the frontend, all types become
resilient unless annotated with the @fixed_layout attribute.
So far, the @fixed_layout attribute only comes into play in SIL type
lowering of structs and enums, which now become address-only unless
they are @fixed_layout. For now, @fixed_layout is also allowed on
classes, but has no effect. In the future, support for less resilient
type lowering within a single resilience domain will be added, with
appropriate loads and stores in function prologs and epilogs.
Resilience is not enabled by default, which gives all types fixed
layout and matches the behavior of the compiler today. Since
we do not want the -enable-resilience flag to change the behavior
of existing compiled modules, only the currently-compiling module,
Sema adds the @fixed_layout flag to all declarations when the flag
is off. To reduce the size of .swiftmodule files, this could become
a flag on the module itself in the future.
The reasoning behind this is that the usual case is building
applications and private frameworks, where there is no need to make
anything resilient.
For the standard library, we can start out with resilience disabled,
while perfoming an audit adding @fixed_layout annotations in the
right places. Once the implementation is robust enough we can then
build the standard library with resilience enabled.
data flow. This should handle some simple RLE. but not phi-node, i.e.
SILArguments.
Also, the new RLE implemented in this patch is disabled by default (behind
a flag). we are working on post-commit review.
Probably SILGenPoly.cpp should be named SILGenThunk.cpp, but I'm saving
that for if I ever extract the duplication between bridging thunks and
re-abstraction thunks.
Refines the results of getReleasingBehavior() by checking the
consumption kind of UnconditionalCheckedCastAddrInst and
CheckedCastAddrBranchInst, as well as whether a CopyAddrInst is an
initialization.
data flow. This should handle some simple RLE. but not phi-node, i.e.
SILArguments.
Also, the new RLE implemented in this patch is disabled by default (behind
a flag). we are working on post-commit review.
This will be used in call graph construction so that we can model calls
to deinits that are potentially called as a result of executing
instructions that can end up releasing memory.
