Add more relevant instructions to dump in MemBehaviorDumper.
Therefore the -enable-mem-behavior-dump-all option can be removed.
Also mem-behavior-all.sil into mem-behavior.sil, because the sil-opt command lines don't differ anymore.
1. Do a better alias analysis for "function-local" objects, like alloc_stack and inout parameters
2. Fully support try_apply and begin/end/abort_apply
So far we fully relied on escape analysis. But escape analysis has some shortcomings with SIL address-types.
Therefore, handle two common cases, alloc_stack and inout parameters, with alias analysis.
This gives better results.
The biggest change here is to do a quick check if the address escapes via an address_to_pointer instructions.
This is in prepration for other bug fixes.
Clarify the SIL utilities that return canonical address values for
formal access given the address used by some memory operation:
- stripAccessMarkers
- getAddressAccess
- getAccessedAddress
These are closely related to the code in MemAccessUtils.
Make sure passes use these utilities consistently so that
optimizations aren't defeated by normal variations in SIL patterns.
Create an isLetAddress() utility alongside these basic utilities to
make sure it is used consistently with the address corresponding to
formal access. When this query is used inconsistently, it defeats
optimization. It can also cause correctness bugs because some
optimizations assume that 'let' initialization is only performed on a
unique address value.
Functional changes to Memory Behavior:
- An instruction with side effects now conservatively still has side
effects even when the queried value is a 'let'. Let values are
certainly sensitive to side effects, such as the parent object being
deallocated.
- Return the correct MemBehavior for begin/end_access markers.
introduce a common superclass, SILNode.
This is in preparation for allowing instructions to have multiple
results. It is also a somewhat more elegant representation for
instructions that have zero results. Instructions that are known
to have exactly one result inherit from a class, SingleValueInstruction,
that subclasses both ValueBase and SILInstruction. Some care must be
taken when working with SILNode pointers and testing for equality;
please see the comment on SILNode for more information.
A number of SIL passes needed to be updated in order to handle this
new distinction between SIL values and SIL instructions.
Note that the SIL parser is now stricter about not trying to assign
a result value from an instruction (like 'return' or 'strong_retain')
that does not produce any.
At some point, pass definitions were heavily macro-ized. Pass
descriptive names were added in two places. This is not only redundant
but a source of confusion. You could waste a lot of time grepping for
the wrong string. I removed all the getName() overrides which, at
around 90 passes, was a fairly significant amount of code bloat.
Any pass that we want to be able to invoke by name from a tool
(sil-opt) or pipeline plan *should* have unique type name, enum value,
commend-line string, and name string. I removed a comment about the
various inliner passes that contradicted that.
Side note: We should be consistent with the policy that a pass is
identified by its type. We have a couple passes, LICM and CSE, which
currently violate that convention.
Before this commit all code relating to handling arguments in SILBasicBlock had
somewhere in the name BB. This is redundant given that the class's name is
already SILBasicBlock. This commit drops those names.
Some examples:
getBBArg() => getArgument()
BBArgList => ArgumentList
bbarg_begin() => args_begin()
As there are no instructions left which produce multiple result values, this is a NFC regarding the generated SIL and generated code.
Although this commit is large, most changes are straightforward adoptions to the changes in the ValueBase and SILValue classes.
