All this does is automate the creation of the ${DIRNAME}_SOURCES variables that we already create and allows for the author to avoid having to prefix with the directory name, i.e.:
set(FOOBAR_SOURCES
FooBar/Source.cpp
PARENT_SCOPE)
=>
silopt_register_sources(
Source.cpp)
Much easier and cleaner to read. I put the code that implements this in the
CMakeLists.txt file just for the SILOptimizer.
The major important thing here is that by using copy_unowned_value we can
guarantee that the non-ownership SIL ARC optimizer will treat the release
associated with the strong_retain_unowned as on a distinc rc-identity from its
argument. As an example of this problem consider the following SILGen like
output:
----
%1 = copy_value %0 : $Builtin.NativeObject
%2 = ref_to_unowned %1
%3 = copy_unowned_value %2
destroy_value %1
...
destroy_value %3
----
In this case, we are converting a strong reference to an unowned value and then
lifetime extending the value past the original value. After eliminating
ownership this lowers to:
----
strong_retain %0 : $Builtin.NativeObject
%1 = ref_to_unowned %0
strong_retain_unowned %1
strong_release %0
...
strong_release %0
----
From an RC identity perspective, we have now blurred the lines in between %3 and
%1 in the previous example. This can then result in the following miscompile:
----
%1 = ref_to_unowned %0
strong_retain_unowned %1
...
strong_release %0
----
In this case, it is possible that we created a lifetime gap that will then cause
strong_retain_unowned to assert. By not lowering copy_unowned_value throughout
the SIL pipeline, we instead get this after lowering:
----
strong_retain %0 : $Builtin.NativeObject
%1 = ref_to_unowned %0
%2 = copy_unowned_value %1
strong_release %0
...
strong_release %2
----
And we do not miscompile since we preserved the high level rc identity
pairing.
There shouldn't be any performance impact since we do not really optimize
strong_retain_unowned at the SIL level. I went through all of the places that
strong_retain_unowned was referenced and added appropriate handling for
copy_unowned_value.
rdar://41328987
**NOTE** I am going to remove strong_retain_unowned in a forthcoming commit. I
just want something more minimal for cherry-picking purposes.
I am tuning a new argument explosion heuristic to reduce code-size. One part of
the heuristic I am playing with is the part of the algorithm that attempts to
figure out if we could eliminate additonal arguments after performing
owned->guaranteed an additional release when we run FSO a second time. Today we
do this unconditionally. I am trying to do it in a more conservative way where
we only do it if we know that we aren't going to increase the number of
arguments too much.
rdar://41146023
This is particularly egrigious since we are only /reading/ from the DenseSet. So
we are basically mallocing/copying a DenseSet just to read from it... I don't
think I need to say more.
rdar://41146023
The compile-time exclusivity diagnostics explicitly allow conflicting accesses
to a struct when it can prove that the two accesses are used to project addresses
for separate stored properties. Unfortunately, the logic that detects this special
case gets confused by Thread Sanitizer's SIL-level instrumentation. This causes
the exclusivity diagnostics to have false positives when TSan is enabled.
To fix this, teach the AccessSummaryAnalysis to ignore TSan builtins when
determining whether an access has a single projected subpath.
rdar://problem/40455335
@effects is too low a level, and not meant for general usage outside
the standard library. Therefore it deserves to be underscored like
other such attributes.
Use AccessedStorageAnalysis to find access markers with no nested conflicts.
This optimization analyzes the scope of each access to determine
whether it contains a potentially conflicting access. If not, then it
can be demoted to an instantaneous check, which still catches
conflicts on any enclosing outer scope.
This removes up to half of the runtime calls associated with
exclusivity checking.
The actual algorithm used here has not changed at all so this is basically a NFC
commit. What this PR does is change the underlying algorithm to return the
operands that it computes internally rather than transforming the operand list
into the user list internally. This enables the callers of the optimization to
find the operand number related to the uses. This makes working with
instructions with multiple operands much easier since one does not need to mess
around with rederiving the operand number from the user instruction/SILValue
pair.
getRCUsers() works now by running getRCUses() internally and then maps the
operand list to the user list.
rdar://38196046
The pattern we see for noescape closure passed to objective c is different:
There is the additional without actually escaping closure sentinel.
rdar://39682865
An interprocedural analysis pass that summarizes the dynamically
enforced formal accesses within a function. These summaries will be
used by a new AccessEnforcementOpts pass to locally fold access scopes
and remove dynamic checks based on whole module analysis.
Make this a generic analysis so that it can be used to analyze any
kind of function effect.
FunctionSideEffect becomes a trivial specialization of the analysis.
The immediate need for this is to introduce an new
AccessedStorageAnalysis, although I foresee it as a generally very
useful utility. This way, new kinds of function effects can be
computed without adding any complexity or compile time to
FunctionSideEffects. We have the flexibility of computing different
kinds of function effects at different points in the pipeline.
In the case of AccessedStorageAnalysis, it will compute both
FunctionSideEffects and FunctionAccessedStorage in the same pass by
implementing a simple wrapper on top of FunctionEffects.
This cleanup reflects my feeling that nested classes make the code
extremely unreadable unless they are very small and either private or
only used directly via its parent class. It's easier to see how these
classes compose with a flat type system.
In addition to enabling new kinds of function effects analyses, I
think this makes the implementation of side effect analysis easier to
understand by separating concerns.
The EscapeAnalysis:canEscapeTo function was actually broken, because it did not detect all escapes of a reference/pointer.
I completely replaced the implementation with the correct one (canObjectOrContentEscapeTo) and removed the now obsolete canObjectOrContentEscapeTo.
Fixes a miscompile.
rdar://problem/39161309
This bug was introduced by the migration to multi-value SILInstructions.
This fix will be tested by copy forwarding.
WARNING: To handle the potential existence of multi-value
instructions, don't simply iterate over the results. You may be
inadvertently skipping instructions with no results.
Details:
RCIdentityFunctionInfo::getRCUsers searches the def-use chain to find
all users. When visiting a use, it checks the result to determine if
it's casting or extracting the original reference operand. If, so it
continues along the def-use chain. So, it simply wasn't visiting
instructions with no results.
I inverted the logic so that the special case now requires identifying
a SingleValueInstruction, while the default case is conservative.
Although I think it is a NFC, it makes it more safe. This change is to align the fix with what I did on the 4.1 branch.
Also remove the not needed $ chars in the function names in the test case.
Will be used to verify that withoutActuallyEscaping's block does not
escape the closure.
``%escaping = is_escaping_closure %closure`` tests the reference count. If the
closure is not uniquely referenced it prints out and error message and
returns true. Otherwise, it returns false. The returned result can be
used with a ``cond_fail %escaping`` instruction to abort the program.
rdar://35525730
