Give ClauseMatrix a dump method that gives nice columnar output of the current decision matrix, and add DEBUG output to emitSwitchStmt so there's more visibility into decision tree generation.
Swift SVN r9519
No intended functionality change yet. For now this gives a slightly better constant factor to the O(n^2) linear scan for subsumed pattern nodes. Later on, for nominal type patterns, this will also give us an opportunity to collect the properties from all the equivalent patterns into one NominalTypePattern specialization.
Swift SVN r9297
Now that we can ask about superclasses outside of the type-checker, we can consider superclass relationships when pattern-matching 'is' patterns, producing better decision trees when a subclass checked is subsumed by a superclass check, a subclass check renders a superclass check redundant, or two classes or orthogonal and a check of one rules out the other.
Swift SVN r8769
Replace the existing suite of checked cast instructions with:
- unconditional_checked_cast, which performs an unconditional cast that aborts on failure (like the former downcast unconditional); and
- checked_cast_br, which performs a conditional pass and branches on whether the cast succeeds, passing the result to the true branch as an argument.
Both instructions take a CheckedCastKind that discriminates the different casting modes formerly discriminated by instruction type. This eliminates a source of null references in SIL and eliminates null SIL addresses completely.
Swift SVN r8696
Tuple exploding happens during RValue construction, so changed the constructor and addElement() method to take the location parameter. The imploding happens on RValue::forwardAsSingleValue and RValue::getAsSingleValue(). Make sure the right SIL locations are passed to all of these
Also, added some missing locations in pattern matching code.
Swift SVN r7916
Switch on address-only unions using the destructive_switch_union_addr instruction. This is safe to do now thanks to r7812: The destructured value will now naturally be cleaned up instead of the invalidated union.
Swift SVN r7821
Before, we left the switch subject rvalue to be cleaned up at the close of the switch's scope. This is a bit wasteful because it keeps the rvalue live long after it's actually needed, and destroying the subject potentially requires replicating a bunch of destructuring we already do in the course of the pattern match. This patch changes things so that, just prior to entering a case, we clean up the destructured occurrence vector we have at the point of entering the case, which should be equivalent to but potentially more efficient than destroying the original subject rvalue.
Swift SVN r7814
I've decided to keep only the location of the scope AST node that corresponds to the cleanup. (Currently, there is no user that needs the originator expression, which caused the cleanup. So keeping things simple.)
Added the cleanup location to the Scope and JumpDest classes, which gets assigned on construction of those. The Scope's and JumpDest locations are used when we emit the cleanup instructions.
We now give better location info for 2 existing tests for definitive initialization.
(+ Rather sparse testing of all this.)
Swift SVN r7764
We mark the branch instructions leading into single epilog code with ReturnLocation/ImplicitReturnLocation. If SIL Gen simplifies the code and merges the code representing the return into the epilog block, the terminator of the epilog block (the ReturnInst) will have the return location info on it. Otherwise, the ReturnInst has the RegularLocation, which represents the enclosing FunctionExpr or Constructor/Destructor Decls.
(I've discussed dropping the optimization from SILGen, and keeping the epilog code canonical, with Adrian; but he said that there might not be any wins in doing so, so keeping it for now.)
Added AutoGeneratedLocation to represent segments of code generated by SILGen. This will be used for thunks and other auto-generated segments.
Swift SVN r7634
