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05df263b84
This pr redefines the relation between lambda lifting and closureiter transformation. Key takeaways: - Lambdalifting now has less distinction between closureiters and regular closures. Namely instead of lifting _all_ closureiter variables, it lifts only those variables it would also lift for simple closure, i.e. those not owned by the closure. - It is now closureiter transformation's responsibility to lift all the locals that need lifting and are not lifted by lambdalifting. So now we lift only those locals that appear in more than one state. The rest remains on stack, yay! - Closureiter transformation always relies on the closure env param created by lambdalifting. Special care taken to make lambdalifting create it even in cases when it's "too early" to lift. - Environments created by lambdalifting will contain `:state` only for closureiters, whereas previously any closure env contained it. IMO this is a more reasonable approach as it simplifies not only lambdalifting, but transf too (e.g. freshVarsForClosureIters is now gone for good). I tried to organize the changes logically by commits, so it might be easier to review this on per commit basis. Some ugliness: - Adding lifting to closureiters transformation I had to repeat this matching of `return result = value` node. I tried to understand why it is needed, but that was just another rabbit hole, so I left it for another time. @Araq your input is welcome. - In the last commit I've reused currently undocumented `liftLocals` pragma for symbols so that closureiter transformation will forcefully lift those even if they don't require lifting otherwise. This is needed for [yasync](https://github.com/yglukhov/yasync) or else it will be very sad. Overall I'm quite happy with the results, I'm seeing some noticeable code size reductions in my projects. Heavy closureiter/async users, please give it a go.
1541 lines
47 KiB
Nim
1541 lines
47 KiB
Nim
#
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#
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# The Nim Compiler
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# (c) Copyright 2018 Nim Contributors
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#
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# See the file "copying.txt", included in this
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# distribution, for details about the copyright.
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#
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# This file implements closure iterator transformations.
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# The main idea is to split the closure iterator body to top level statements.
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# The body is split by yield statement.
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#
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# Example:
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# while a > 0:
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# echo "hi"
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# yield a
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# dec a
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#
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# Should be transformed to:
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# case :state
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# of 0:
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# if a > 0:
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# echo "hi"
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# :state = 1 # Next state
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# return a # yield
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# else:
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# :state = 2 # Next state
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# break :stateLoop # Proceed to the next state
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# of 1:
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# dec a
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# :state = 0 # Next state
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# break :stateLoop # Proceed to the next state
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# of 2:
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# :state = -1 # End of execution
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# else:
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# return
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# Lambdalifting treats :state variable specially, it should always end up
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# as the first field in env. Currently C codegen depends on this behavior.
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# One special subtransformation is nkStmtListExpr lowering.
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# Example:
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# template foo(): int =
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# yield 1
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# 2
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#
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# iterator it(): int {.closure.} =
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# if foo() == 2:
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# yield 3
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#
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# If a nkStmtListExpr has yield inside, it has first to be lowered to:
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# yield 1
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# :tmpSlLower = 2
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# if :tmpSlLower == 2:
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# yield 3
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# nkTryStmt Transformations:
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# If the iter has an nkTryStmt with a yield inside
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# - the closure iter is promoted to have exceptions (ctx.hasExceptions = true)
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# - exception table is created. This is a const array, where
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# `abs(exceptionTable[i])` is a state idx to which we should jump from state
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# `i` should exception be raised in state `i`. For all states in `try` block
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# the target state is `except` block. For all states in `except` block
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# the target state is `finally` block. For all other states there is no
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# target state (0, as the first block can never be neither except nor finally).
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# `exceptionTable[i]` is < 0 if `abs(exceptionTable[i])` is except block,
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# and > 0, for finally block.
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# - local variable :curExc is created
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# - the iter body is wrapped into a
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# try:
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# closureIterSetupExc(:curExc)
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# ...body...
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# catch:
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# :state = exceptionTable[:state]
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# if :state == 0: raise # No state that could handle exception
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# :unrollFinally = :state > 0 # Target state is finally
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# if :state < 0:
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# :state = -:state
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# :curExc = getCurrentException()
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#
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# nkReturnStmt within a try/except/finally now has to behave differently as we
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# want the nearest finally block to be executed before the return, thus it is
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# transformed to:
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# :tmpResult = returnValue (if return doesn't have a value, this is skipped)
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# :unrollFinally = true
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# goto nearestFinally (or -1 if not exists)
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#
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# Example:
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#
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# try:
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# yield 0
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# raise ...
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# except:
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# yield 1
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# return 3
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# finally:
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# yield 2
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#
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# Is transformed to (yields are left in place for example simplicity,
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# in reality the code is subdivided even more, as described above):
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#
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# case :state
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# of 0: # Try
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# yield 0
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# raise ...
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# :state = 2 # What would happen should we not raise
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# break :stateLoop
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# of 1: # Except
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# yield 1
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# :tmpResult = 3 # Return
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# :unrollFinally = true # Return
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# :state = 2 # Goto Finally
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# break :stateLoop
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# :state = 2 # What would happen should we not return
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# break :stateLoop
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# of 2: # Finally
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# yield 2
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# if :unrollFinally: # This node is created by `newEndFinallyNode`
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# if :curExc.isNil:
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# if nearestFinally == 0:
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# return :tmpResult
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# else:
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# :state = nearestFinally # bubble up
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# else:
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# closureIterSetupExc(nil)
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# raise
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# state = -1 # Goto next state. In this case we just exit
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# break :stateLoop
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# else:
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# return
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import
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ast, msgs, idents,
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renderer, magicsys, lowerings, lambdalifting, modulegraphs, lineinfos,
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options
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import std/tables
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when defined(nimPreviewSlimSystem):
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import std/assertions
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type
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Ctx = object
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g: ModuleGraph
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fn: PSym
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tmpResultSym: PSym # Used when we return, but finally has to interfere
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unrollFinallySym: PSym # Indicates that we're unrolling finally states (either exception happened or premature return)
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curExcSym: PSym # Current exception
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states: seq[tuple[label: int, body: PNode]] # The resulting states.
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blockLevel: int # Temp used to transform break and continue stmts
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stateLoopLabel: PSym # Label to break on, when jumping between states.
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exitStateIdx: int # index of the last state
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tempVarId: int # unique name counter
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tempVars: PNode # Temp var decls, nkVarSection
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exceptionTable: seq[int] # For state `i` jump to state `exceptionTable[i]` if exception is raised
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hasExceptions: bool # Does closure have yield in try?
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curExcHandlingState: int # Negative for except, positive for finally
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nearestFinally: int # Index of the nearest finally block. For try/except it
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# is their finally. For finally it is parent finally. Otherwise -1
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idgen: IdGenerator
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varStates: Table[ItemId, int] # Used to detect if local variable belongs to multiple states
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const
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nkSkip = {nkEmpty..nkNilLit, nkTemplateDef, nkTypeSection, nkStaticStmt,
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nkCommentStmt, nkMixinStmt, nkBindStmt} + procDefs
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emptyStateLabel = -1
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localNotSeen = -1
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localRequiresLifting = -2
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proc newStateAccess(ctx: var Ctx): PNode =
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result = rawIndirectAccess(newSymNode(getEnvParam(ctx.fn)),
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getStateField(ctx.g, ctx.fn), ctx.fn.info)
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proc newStateAssgn(ctx: var Ctx, toValue: PNode): PNode =
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# Creates state assignment:
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# :state = toValue
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newTree(nkAsgn, ctx.newStateAccess(), toValue)
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proc newStateAssgn(ctx: var Ctx, stateNo: int = -2): PNode =
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# Creates state assignment:
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# :state = stateNo
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ctx.newStateAssgn(newIntTypeNode(stateNo, ctx.g.getSysType(TLineInfo(), tyInt)))
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proc newEnvVar(ctx: var Ctx, name: string, typ: PType): PSym =
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result = newSym(skVar, getIdent(ctx.g.cache, name), ctx.idgen, ctx.fn, ctx.fn.info)
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result.typ = typ
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result.flags.incl sfNoInit
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assert(not typ.isNil, "Env var needs a type")
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let envParam = getEnvParam(ctx.fn)
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# let obj = envParam.typ.lastSon
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result = addUniqueField(envParam.typ.elementType, result, ctx.g.cache, ctx.idgen)
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proc newEnvVarAccess(ctx: Ctx, s: PSym): PNode =
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result = rawIndirectAccess(newSymNode(getEnvParam(ctx.fn)), s, ctx.fn.info)
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proc newTempVarAccess(ctx: Ctx, s: PSym): PNode =
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result = newSymNode(s, ctx.fn.info)
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proc newTmpResultAccess(ctx: var Ctx): PNode =
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if ctx.tmpResultSym.isNil:
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ctx.tmpResultSym = ctx.newEnvVar(":tmpResult", ctx.fn.typ.returnType)
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ctx.newEnvVarAccess(ctx.tmpResultSym)
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proc newUnrollFinallyAccess(ctx: var Ctx, info: TLineInfo): PNode =
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if ctx.unrollFinallySym.isNil:
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ctx.unrollFinallySym = ctx.newEnvVar(":unrollFinally", ctx.g.getSysType(info, tyBool))
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ctx.newEnvVarAccess(ctx.unrollFinallySym)
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proc newCurExcAccess(ctx: var Ctx): PNode =
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if ctx.curExcSym.isNil:
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ctx.curExcSym = ctx.newEnvVar(":curExc", ctx.g.callCodegenProc("getCurrentException").typ)
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ctx.newEnvVarAccess(ctx.curExcSym)
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proc newState(ctx: var Ctx, n, gotoOut: PNode): int =
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# Creates a new state, adds it to the context fills out `gotoOut` so that it
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# will goto this state.
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# Returns index of the newly created state
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result = ctx.states.len
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let resLit = ctx.g.newIntLit(n.info, result)
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ctx.states.add((result, n))
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ctx.exceptionTable.add(ctx.curExcHandlingState)
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if not gotoOut.isNil:
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assert(gotoOut.len == 0)
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gotoOut.add(ctx.g.newIntLit(gotoOut.info, result))
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proc toStmtList(n: PNode): PNode =
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result = n
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if result.kind notin {nkStmtList, nkStmtListExpr}:
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result = newNodeI(nkStmtList, n.info)
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result.add(n)
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proc addGotoOut(n: PNode, gotoOut: PNode): PNode =
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# Make sure `n` is a stmtlist, and ends with `gotoOut`
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result = toStmtList(n)
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if result.len == 0 or result[^1].kind != nkGotoState:
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result.add(gotoOut)
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proc newTempVarDef(ctx: Ctx, s: PSym, initialValue: PNode): PNode =
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var v = initialValue
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if v == nil:
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v = ctx.g.emptyNode
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newTree(nkVarSection, newTree(nkIdentDefs, newSymNode(s), ctx.g.emptyNode, v))
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proc newTempVar(ctx: var Ctx, typ: PType, parent: PNode, initialValue: PNode = nil): PSym =
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result = newSym(skVar, getIdent(ctx.g.cache, ":tmpSlLower" & $ctx.tempVarId), ctx.idgen, ctx.fn, ctx.fn.info)
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inc ctx.tempVarId
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result.typ = typ
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assert(not typ.isNil, "Temp var needs a type")
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parent.add(ctx.newTempVarDef(result, initialValue))
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proc hasYields(n: PNode): bool =
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# TODO: This is very inefficient. It traverses the node, looking for nkYieldStmt.
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case n.kind
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of nkYieldStmt:
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result = true
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of nkSkip:
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result = false
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else:
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result = false
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for i in ord(n.kind == nkCast)..<n.len:
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if n[i].hasYields:
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result = true
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break
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proc transformBreaksAndContinuesInWhile(ctx: var Ctx, n: PNode, before, after: PNode): PNode =
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result = n
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case n.kind
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of nkSkip:
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discard
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of nkWhileStmt: discard # Do not recurse into nested whiles
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of nkContinueStmt:
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result = before
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of nkBlockStmt:
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inc ctx.blockLevel
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result[1] = ctx.transformBreaksAndContinuesInWhile(result[1], before, after)
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dec ctx.blockLevel
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of nkBreakStmt:
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if ctx.blockLevel == 0:
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result = after
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else:
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for i in 0..<n.len:
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n[i] = ctx.transformBreaksAndContinuesInWhile(n[i], before, after)
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proc transformBreaksInBlock(ctx: var Ctx, n: PNode, label, after: PNode): PNode =
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result = n
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case n.kind
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of nkSkip:
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discard
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of nkBlockStmt, nkWhileStmt:
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inc ctx.blockLevel
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result[1] = ctx.transformBreaksInBlock(result[1], label, after)
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dec ctx.blockLevel
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of nkBreakStmt:
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if n[0].kind == nkEmpty:
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if ctx.blockLevel == 0:
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result = after
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else:
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if label.kind == nkSym and n[0].sym == label.sym:
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result = after
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else:
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for i in 0..<n.len:
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n[i] = ctx.transformBreaksInBlock(n[i], label, after)
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proc newNullifyCurExc(ctx: var Ctx, info: TLineInfo): PNode =
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# :curEcx = nil
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let curExc = ctx.newCurExcAccess()
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curExc.info = info
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let nilnode = newNode(nkNilLit)
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nilnode.typ = curExc.typ
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result = newTree(nkAsgn, curExc, nilnode)
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proc newOr(g: ModuleGraph, a, b: PNode): PNode {.inline.} =
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result = newTree(nkCall, newSymNode(g.getSysMagic(a.info, "or", mOr)), a, b)
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result.typ = g.getSysType(a.info, tyBool)
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result.info = a.info
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proc collectExceptState(ctx: var Ctx, n: PNode): PNode {.inline.} =
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var ifStmt = newNodeI(nkIfStmt, n.info)
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let g = ctx.g
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for c in n:
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if c.kind == nkExceptBranch:
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var ifBranch: PNode
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if c.len > 1:
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var cond: PNode = nil
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for i in 0..<c.len - 1:
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assert(c[i].kind == nkType)
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let nextCond = newTree(nkCall,
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newSymNode(g.getSysMagic(c.info, "of", mOf)),
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g.callCodegenProc("getCurrentException"),
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c[i])
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nextCond.typ = ctx.g.getSysType(c.info, tyBool)
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nextCond.info = c.info
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if cond.isNil:
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cond = nextCond
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else:
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cond = g.newOr(cond, nextCond)
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ifBranch = newNodeI(nkElifBranch, c.info)
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ifBranch.add(cond)
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else:
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if ifStmt.len == 0:
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ifStmt = newNodeI(nkStmtList, c.info)
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ifBranch = newNodeI(nkStmtList, c.info)
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else:
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ifBranch = newNodeI(nkElse, c.info)
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ifBranch.add(c[^1])
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ifStmt.add(ifBranch)
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if ifStmt.len != 0:
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result = newTree(nkStmtList, ctx.newNullifyCurExc(n.info), ifStmt)
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else:
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result = ctx.g.emptyNode
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proc addElseToExcept(ctx: var Ctx, n: PNode) =
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if n.kind == nkStmtList and n[1].kind == nkIfStmt and n[1][^1].kind != nkElse:
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# Not all cases are covered
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let branchBody = newNodeI(nkStmtList, n.info)
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block: # :unrollFinally = true
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branchBody.add(newTree(nkAsgn,
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ctx.newUnrollFinallyAccess(n.info),
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newIntTypeNode(1, ctx.g.getSysType(n.info, tyBool))))
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block: # :curExc = getCurrentException()
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branchBody.add(newTree(nkAsgn,
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ctx.newCurExcAccess(),
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ctx.g.callCodegenProc("getCurrentException")))
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block: # goto nearestFinally
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branchBody.add(newTree(nkGotoState, ctx.g.newIntLit(n.info, ctx.nearestFinally)))
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let elseBranch = newTree(nkElse, branchBody)
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n[1].add(elseBranch)
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proc getFinallyNode(ctx: var Ctx, n: PNode): PNode =
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result = n[^1]
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if result.kind == nkFinally:
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result = result[0]
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else:
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result = ctx.g.emptyNode
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proc hasYieldsInExpressions(n: PNode): bool =
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case n.kind
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of nkSkip:
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result = false
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of nkStmtListExpr:
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if isEmptyType(n.typ):
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result = false
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for c in n:
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if c.hasYieldsInExpressions:
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return true
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else:
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result = n.hasYields
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of nkCast:
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result = false
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for i in 1..<n.len:
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if n[i].hasYieldsInExpressions:
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return true
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else:
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result = false
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for c in n:
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if c.hasYieldsInExpressions:
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return true
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proc exprToStmtList(n: PNode): tuple[s, res: PNode] =
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assert(n.kind == nkStmtListExpr)
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result = (newNodeI(nkStmtList, n.info), nil)
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result.s.sons = @[]
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var n = n
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while n.kind == nkStmtListExpr:
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result.s.sons.add(n.sons)
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result.s.sons.setLen(result.s.len - 1) # delete last son
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n = n[^1]
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result.res = n
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proc newTempVarAsgn(ctx: Ctx, s: PSym, v: PNode): PNode =
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if isEmptyType(v.typ):
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result = v
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else:
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result = newTree(nkFastAsgn, ctx.newTempVarAccess(s), v)
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result.info = v.info
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proc addExprAssgn(ctx: Ctx, output, input: PNode, sym: PSym) =
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if input.kind == nkStmtListExpr:
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let (st, res) = exprToStmtList(input)
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output.add(st)
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output.add(ctx.newTempVarAsgn(sym, res))
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else:
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output.add(ctx.newTempVarAsgn(sym, input))
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proc convertExprBodyToAsgn(ctx: Ctx, exprBody: PNode, res: PSym): PNode =
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result = newNodeI(nkStmtList, exprBody.info)
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ctx.addExprAssgn(result, exprBody, res)
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proc newNotCall(g: ModuleGraph; e: PNode): PNode =
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result = newTree(nkCall, newSymNode(g.getSysMagic(e.info, "not", mNot), e.info), e)
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result.typ = g.getSysType(e.info, tyBool)
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|
proc boolLit(g: ModuleGraph; info: TLineInfo; value: bool): PNode =
|
|
result = newIntLit(g, info, ord value)
|
|
result.typ = getSysType(g, info, tyBool)
|
|
|
|
proc captureVar(c: var Ctx, s: PSym) =
|
|
if c.varStates.getOrDefault(s.itemId) != localRequiresLifting:
|
|
c.varStates[s.itemId] = localRequiresLifting # Mark this variable for lifting
|
|
let e = getEnvParam(c.fn)
|
|
discard addField(e.typ.elementType, s, c.g.cache, c.idgen)
|
|
|
|
proc lowerStmtListExprs(ctx: var Ctx, n: PNode, needsSplit: var bool): PNode =
|
|
result = n
|
|
case n.kind
|
|
of nkSkip:
|
|
discard
|
|
|
|
of nkYieldStmt:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
result.add(n)
|
|
|
|
needsSplit = true
|
|
|
|
of nkPar, nkObjConstr, nkTupleConstr, nkBracket:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
if n.typ.isNil: internalError(ctx.g.config, "lowerStmtListExprs: constr typ.isNil")
|
|
result.typ = n.typ
|
|
|
|
for i in 0..<n.len:
|
|
case n[i].kind
|
|
of nkExprColonExpr:
|
|
if n[i][1].kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[i][1])
|
|
result.add(st)
|
|
n[i][1] = ex
|
|
of nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[i])
|
|
result.add(st)
|
|
n[i] = ex
|
|
else: discard
|
|
result.add(n)
|
|
|
|
of nkIfStmt, nkIfExpr:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
var tmp: PSym = nil
|
|
let isExpr = not isEmptyType(n.typ)
|
|
if isExpr:
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
tmp = ctx.newTempVar(n.typ, result)
|
|
else:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
|
|
var curS = result
|
|
|
|
for branch in n:
|
|
case branch.kind
|
|
of nkElseExpr, nkElse:
|
|
if isExpr:
|
|
let branchBody = newNodeI(nkStmtList, branch.info)
|
|
ctx.addExprAssgn(branchBody, branch[0], tmp)
|
|
let newBranch = newTree(nkElse, branchBody)
|
|
curS.add(newBranch)
|
|
else:
|
|
curS.add(branch)
|
|
|
|
of nkElifExpr, nkElifBranch:
|
|
var newBranch: PNode
|
|
if branch[0].kind == nkStmtListExpr:
|
|
let (st, res) = exprToStmtList(branch[0])
|
|
let elseBody = newTree(nkStmtList, st)
|
|
|
|
newBranch = newTree(nkElifBranch, res, branch[1])
|
|
|
|
let newIf = newTree(nkIfStmt, newBranch)
|
|
elseBody.add(newIf)
|
|
if curS.kind == nkIfStmt:
|
|
let newElse = newNodeI(nkElse, branch.info)
|
|
newElse.add(elseBody)
|
|
curS.add(newElse)
|
|
else:
|
|
curS.add(elseBody)
|
|
curS = newIf
|
|
else:
|
|
newBranch = branch
|
|
if curS.kind == nkIfStmt:
|
|
curS.add(newBranch)
|
|
else:
|
|
let newIf = newTree(nkIfStmt, newBranch)
|
|
curS.add(newIf)
|
|
curS = newIf
|
|
|
|
if isExpr:
|
|
let branchBody = newNodeI(nkStmtList, branch[1].info)
|
|
ctx.addExprAssgn(branchBody, branch[1], tmp)
|
|
newBranch[1] = branchBody
|
|
|
|
else:
|
|
internalError(ctx.g.config, "lowerStmtListExpr(nkIf): " & $branch.kind)
|
|
|
|
if isExpr: result.add(ctx.newTempVarAccess(tmp))
|
|
|
|
of nkTryStmt, nkHiddenTryStmt:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
let isExpr = not isEmptyType(n.typ)
|
|
|
|
if isExpr:
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
let tmp = ctx.newTempVar(n.typ, result)
|
|
|
|
n[0] = ctx.convertExprBodyToAsgn(n[0], tmp)
|
|
for i in 1..<n.len:
|
|
let branch = n[i]
|
|
case branch.kind
|
|
of nkExceptBranch:
|
|
if branch[0].kind == nkType:
|
|
branch[1] = ctx.convertExprBodyToAsgn(branch[1], tmp)
|
|
else:
|
|
branch[0] = ctx.convertExprBodyToAsgn(branch[0], tmp)
|
|
of nkFinally:
|
|
discard
|
|
else:
|
|
internalError(ctx.g.config, "lowerStmtListExpr(nkTryStmt): " & $branch.kind)
|
|
result.add(n)
|
|
result.add(ctx.newTempVarAccess(tmp))
|
|
|
|
of nkCaseStmt:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
|
|
let isExpr = not isEmptyType(n.typ)
|
|
|
|
if isExpr:
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
let tmp = ctx.newTempVar(n.typ, result)
|
|
|
|
if n[0].kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
|
|
for i in 1..<n.len:
|
|
let branch = n[i]
|
|
case branch.kind
|
|
of nkOfBranch:
|
|
branch[^1] = ctx.convertExprBodyToAsgn(branch[^1], tmp)
|
|
of nkElse:
|
|
branch[0] = ctx.convertExprBodyToAsgn(branch[0], tmp)
|
|
else:
|
|
internalError(ctx.g.config, "lowerStmtListExpr(nkCaseStmt): " & $branch.kind)
|
|
result.add(n)
|
|
result.add(ctx.newTempVarAccess(tmp))
|
|
elif n[0].kind == nkStmtListExpr:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
result.add(n)
|
|
|
|
of nkCallKinds, nkChckRange, nkChckRangeF, nkChckRange64:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
let isExpr = not isEmptyType(n.typ)
|
|
|
|
if isExpr:
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
else:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
|
|
if n[0].kind == nkSym and n[0].sym.magic in {mAnd, mOr}: # `and`/`or` short cirquiting
|
|
var cond = n[1]
|
|
if cond.kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(cond)
|
|
result.add(st)
|
|
cond = ex
|
|
|
|
let tmp = ctx.newTempVar(cond.typ, result, cond)
|
|
# result.add(ctx.newTempVarAsgn(tmp, cond))
|
|
|
|
var check = ctx.newTempVarAccess(tmp)
|
|
if n[0].sym.magic == mOr:
|
|
check = ctx.g.newNotCall(check)
|
|
|
|
cond = n[2]
|
|
let ifBody = newNodeI(nkStmtList, cond.info)
|
|
if cond.kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(cond)
|
|
ifBody.add(st)
|
|
cond = ex
|
|
ifBody.add(ctx.newTempVarAsgn(tmp, cond))
|
|
|
|
let ifBranch = newTree(nkElifBranch, check, ifBody)
|
|
let ifNode = newTree(nkIfStmt, ifBranch)
|
|
result.add(ifNode)
|
|
result.add(ctx.newTempVarAccess(tmp))
|
|
else:
|
|
for i in 0..<n.len:
|
|
if n[i].kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[i])
|
|
result.add(st)
|
|
n[i] = ex
|
|
|
|
if n[i].kind in nkCallKinds: # XXX: This should better be some sort of side effect tracking
|
|
let tmp = ctx.newTempVar(n[i].typ, result, n[i])
|
|
# result.add(ctx.newTempVarAsgn(tmp, n[i]))
|
|
n[i] = ctx.newTempVarAccess(tmp)
|
|
|
|
result.add(n)
|
|
|
|
of nkVarSection, nkLetSection:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
for c in n:
|
|
let varSect = newNodeI(n.kind, n.info)
|
|
varSect.add(c)
|
|
var ns = false
|
|
c[^1] = ctx.lowerStmtListExprs(c[^1], ns)
|
|
if ns:
|
|
needsSplit = true
|
|
let (st, ex) = exprToStmtList(c[^1])
|
|
result.add(st)
|
|
c[^1] = ex
|
|
for i in 0 .. c.len - 3:
|
|
if c[i].kind == nkSym:
|
|
let s = c[i].sym
|
|
if sfForceLift in s.flags:
|
|
ctx.captureVar(s)
|
|
|
|
result.add(varSect)
|
|
|
|
of nkDiscardStmt, nkReturnStmt, nkRaiseStmt:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtList, n.info)
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
result.add(n)
|
|
|
|
of nkCast, nkHiddenStdConv, nkHiddenSubConv, nkConv, nkObjDownConv,
|
|
nkDerefExpr, nkHiddenDeref:
|
|
var ns = false
|
|
for i in ord(n.kind == nkCast)..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
let (st, ex) = exprToStmtList(n[^1])
|
|
result.add(st)
|
|
n[^1] = ex
|
|
result.add(n)
|
|
|
|
of nkAsgn, nkFastAsgn, nkSinkAsgn:
|
|
var ns = false
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], ns)
|
|
|
|
if ns:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtList, n.info)
|
|
if n[0].kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
|
|
if n[1].kind == nkStmtListExpr:
|
|
let (st, ex) = exprToStmtList(n[1])
|
|
result.add(st)
|
|
n[1] = ex
|
|
|
|
result.add(n)
|
|
|
|
of nkBracketExpr:
|
|
var lhsNeedsSplit = false
|
|
var rhsNeedsSplit = false
|
|
n[0] = ctx.lowerStmtListExprs(n[0], lhsNeedsSplit)
|
|
n[1] = ctx.lowerStmtListExprs(n[1], rhsNeedsSplit)
|
|
if lhsNeedsSplit or rhsNeedsSplit:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
if lhsNeedsSplit:
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
|
|
if rhsNeedsSplit:
|
|
let (st, ex) = exprToStmtList(n[1])
|
|
result.add(st)
|
|
n[1] = ex
|
|
result.add(n)
|
|
|
|
of nkWhileStmt:
|
|
var condNeedsSplit = false
|
|
n[0] = ctx.lowerStmtListExprs(n[0], condNeedsSplit)
|
|
var bodyNeedsSplit = false
|
|
n[1] = ctx.lowerStmtListExprs(n[1], bodyNeedsSplit)
|
|
|
|
if condNeedsSplit or bodyNeedsSplit:
|
|
needsSplit = true
|
|
|
|
if condNeedsSplit:
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
let brk = newTree(nkBreakStmt, ctx.g.emptyNode)
|
|
let branch = newTree(nkElifBranch, ctx.g.newNotCall(ex), brk)
|
|
let check = newTree(nkIfStmt, branch)
|
|
let newBody = newTree(nkStmtList, st, check, n[1])
|
|
|
|
n[0] = ctx.g.boolLit(n[0].info, true)
|
|
n[1] = newBody
|
|
|
|
of nkDotExpr, nkCheckedFieldExpr:
|
|
var ns = false
|
|
n[0] = ctx.lowerStmtListExprs(n[0], ns)
|
|
if ns:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
let (st, ex) = exprToStmtList(n[0])
|
|
result.add(st)
|
|
n[0] = ex
|
|
result.add(n)
|
|
|
|
of nkBlockExpr:
|
|
var ns = false
|
|
n[1] = ctx.lowerStmtListExprs(n[1], ns)
|
|
if ns:
|
|
needsSplit = true
|
|
result = newNodeI(nkStmtListExpr, n.info)
|
|
result.typ = n.typ
|
|
let (st, ex) = exprToStmtList(n[1])
|
|
n.transitionSonsKind(nkBlockStmt)
|
|
n.typ = nil
|
|
n[1] = st
|
|
result.add(n)
|
|
result.add(ex)
|
|
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.lowerStmtListExprs(n[i], needsSplit)
|
|
|
|
proc newEndFinallyNode(ctx: var Ctx, info: TLineInfo): PNode =
|
|
# Generate the following code:
|
|
# if :unrollFinally:
|
|
# if :curExc.isNil:
|
|
# if nearestFinally == 0:
|
|
# return :tmpResult
|
|
# else:
|
|
# :state = nearestFinally # bubble up
|
|
# else:
|
|
# raise
|
|
let curExc = ctx.newCurExcAccess()
|
|
let nilnode = newNode(nkNilLit)
|
|
nilnode.typ = curExc.typ
|
|
let cmp = newTree(nkCall, newSymNode(ctx.g.getSysMagic(info, "==", mEqRef), info), curExc, nilnode)
|
|
cmp.typ = ctx.g.getSysType(info, tyBool)
|
|
|
|
let retStmt =
|
|
if ctx.nearestFinally == 0:
|
|
# last finally, we can return
|
|
let retValue = if ctx.fn.typ.returnType.isNil:
|
|
ctx.g.emptyNode
|
|
else:
|
|
newTree(nkFastAsgn,
|
|
newSymNode(getClosureIterResult(ctx.g, ctx.fn, ctx.idgen), info),
|
|
ctx.newTmpResultAccess())
|
|
newTree(nkReturnStmt, retValue)
|
|
else:
|
|
# bubble up to next finally
|
|
newTree(nkGotoState, ctx.g.newIntLit(info, ctx.nearestFinally))
|
|
|
|
let branch = newTree(nkElifBranch, cmp, retStmt)
|
|
|
|
let nullifyExc = newTree(nkCall, newSymNode(ctx.g.getCompilerProc("closureIterSetupExc")), nilnode)
|
|
nullifyExc.info = info
|
|
let raiseStmt = newTree(nkRaiseStmt, curExc)
|
|
raiseStmt.info = info
|
|
let elseBranch = newTree(nkElse, newTree(nkStmtList, nullifyExc, raiseStmt))
|
|
|
|
let ifBody = newTree(nkIfStmt, branch, elseBranch)
|
|
let elifBranch = newTree(nkElifBranch, ctx.newUnrollFinallyAccess(info), ifBody)
|
|
elifBranch.info = info
|
|
result = newTree(nkIfStmt, elifBranch)
|
|
|
|
proc transformReturnsInTry(ctx: var Ctx, n: PNode): PNode =
|
|
result = n
|
|
# TODO: This is very inefficient. It traverses the node, looking for nkYieldStmt.
|
|
case n.kind
|
|
of nkReturnStmt:
|
|
# We're somewhere in try, transform to finally unrolling
|
|
if ctx.nearestFinally == 0:
|
|
# return is within the finally
|
|
return
|
|
|
|
result = newNodeI(nkStmtList, n.info)
|
|
|
|
block: # :unrollFinally = true
|
|
let asgn = newNodeI(nkAsgn, n.info)
|
|
asgn.add(ctx.newUnrollFinallyAccess(n.info))
|
|
asgn.add(newIntTypeNode(1, ctx.g.getSysType(n.info, tyBool)))
|
|
result.add(asgn)
|
|
|
|
if n[0].kind != nkEmpty:
|
|
let asgnTmpResult = newNodeI(nkAsgn, n.info)
|
|
asgnTmpResult.add(ctx.newTmpResultAccess())
|
|
let x = if n[0].kind in {nkAsgn, nkFastAsgn, nkSinkAsgn}: n[0][1] else: n[0]
|
|
asgnTmpResult.add(x)
|
|
result.add(asgnTmpResult)
|
|
|
|
result.add(ctx.newNullifyCurExc(n.info))
|
|
|
|
let goto = newTree(nkGotoState, ctx.g.newIntLit(n.info, ctx.nearestFinally))
|
|
result.add(goto)
|
|
|
|
of nkSkip:
|
|
discard
|
|
of nkTryStmt:
|
|
if n.hasYields:
|
|
# the inner try will handle these transformations
|
|
discard
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformReturnsInTry(n[i])
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformReturnsInTry(n[i])
|
|
|
|
proc transformClosureIteratorBody(ctx: var Ctx, n: PNode, gotoOut: PNode): PNode =
|
|
result = n
|
|
case n.kind
|
|
of nkSkip: discard
|
|
|
|
of nkStmtList, nkStmtListExpr:
|
|
result = addGotoOut(result, gotoOut)
|
|
for i in 0..<n.len:
|
|
if n[i].hasYields:
|
|
# Create a new split
|
|
let go = newNodeI(nkGotoState, n[i].info)
|
|
n[i] = ctx.transformClosureIteratorBody(n[i], go)
|
|
|
|
let s = newNodeI(nkStmtList, n[i + 1].info)
|
|
for j in i + 1..<n.len:
|
|
s.add(n[j])
|
|
|
|
n.sons.setLen(i + 1)
|
|
discard ctx.newState(s, go)
|
|
if ctx.transformClosureIteratorBody(s, gotoOut) != s:
|
|
internalError(ctx.g.config, "transformClosureIteratorBody != s")
|
|
break
|
|
|
|
of nkYieldStmt:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
result.add(n)
|
|
result.add(gotoOut)
|
|
|
|
of nkElse, nkElseExpr:
|
|
result[0] = addGotoOut(result[0], gotoOut)
|
|
result[0] = ctx.transformClosureIteratorBody(result[0], gotoOut)
|
|
|
|
of nkElifBranch, nkElifExpr, nkOfBranch:
|
|
result[^1] = addGotoOut(result[^1], gotoOut)
|
|
result[^1] = ctx.transformClosureIteratorBody(result[^1], gotoOut)
|
|
|
|
of nkIfStmt, nkCaseStmt:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformClosureIteratorBody(n[i], gotoOut)
|
|
if n[^1].kind != nkElse:
|
|
# We don't have an else branch, but every possible branch has to end with
|
|
# gotoOut, so add else here.
|
|
let elseBranch = newTree(nkElse, gotoOut)
|
|
n.add(elseBranch)
|
|
|
|
of nkWhileStmt:
|
|
# while e:
|
|
# s
|
|
# ->
|
|
# BEGIN_STATE:
|
|
# if e:
|
|
# s
|
|
# goto BEGIN_STATE
|
|
# else:
|
|
# goto OUT
|
|
|
|
result = newNodeI(nkGotoState, n.info)
|
|
|
|
let s = newNodeI(nkStmtList, n.info)
|
|
discard ctx.newState(s, result)
|
|
let ifNode = newNodeI(nkIfStmt, n.info)
|
|
let elifBranch = newNodeI(nkElifBranch, n.info)
|
|
elifBranch.add(n[0])
|
|
|
|
var body = addGotoOut(n[1], result)
|
|
|
|
body = ctx.transformBreaksAndContinuesInWhile(body, result, gotoOut)
|
|
body = ctx.transformClosureIteratorBody(body, result)
|
|
|
|
elifBranch.add(body)
|
|
ifNode.add(elifBranch)
|
|
|
|
let elseBranch = newTree(nkElse, gotoOut)
|
|
ifNode.add(elseBranch)
|
|
s.add(ifNode)
|
|
|
|
of nkBlockStmt:
|
|
result[1] = addGotoOut(result[1], gotoOut)
|
|
result[1] = ctx.transformBreaksInBlock(result[1], result[0], gotoOut)
|
|
result[1] = ctx.transformClosureIteratorBody(result[1], gotoOut)
|
|
|
|
of nkTryStmt, nkHiddenTryStmt:
|
|
# See explanation above about how this works
|
|
ctx.hasExceptions = true
|
|
|
|
result = newNodeI(nkGotoState, n.info)
|
|
var tryBody = toStmtList(n[0])
|
|
var exceptBody = ctx.collectExceptState(n)
|
|
var finallyBody = newTree(nkStmtList, getFinallyNode(ctx, n))
|
|
finallyBody = ctx.transformReturnsInTry(finallyBody)
|
|
finallyBody.add(ctx.newEndFinallyNode(finallyBody.info))
|
|
|
|
# The following index calculation is based on the knowledge how state
|
|
# indexes are assigned
|
|
let tryIdx = ctx.states.len
|
|
var exceptIdx, finallyIdx: int
|
|
if exceptBody.kind != nkEmpty:
|
|
exceptIdx = -(tryIdx + 1)
|
|
finallyIdx = tryIdx + 2
|
|
else:
|
|
exceptIdx = tryIdx + 1
|
|
finallyIdx = tryIdx + 1
|
|
|
|
let outToFinally = newNodeI(nkGotoState, finallyBody.info)
|
|
|
|
block: # Create initial states.
|
|
let oldExcHandlingState = ctx.curExcHandlingState
|
|
ctx.curExcHandlingState = exceptIdx
|
|
let realTryIdx = ctx.newState(tryBody, result)
|
|
assert(realTryIdx == tryIdx)
|
|
|
|
if exceptBody.kind != nkEmpty:
|
|
ctx.curExcHandlingState = finallyIdx
|
|
let realExceptIdx = ctx.newState(exceptBody, nil)
|
|
assert(realExceptIdx == -exceptIdx)
|
|
|
|
ctx.curExcHandlingState = oldExcHandlingState
|
|
let realFinallyIdx = ctx.newState(finallyBody, outToFinally)
|
|
assert(realFinallyIdx == finallyIdx)
|
|
|
|
block: # Subdivide the states
|
|
let oldNearestFinally = ctx.nearestFinally
|
|
ctx.nearestFinally = finallyIdx
|
|
|
|
let oldExcHandlingState = ctx.curExcHandlingState
|
|
|
|
ctx.curExcHandlingState = exceptIdx
|
|
|
|
if ctx.transformReturnsInTry(tryBody) != tryBody:
|
|
internalError(ctx.g.config, "transformReturnsInTry != tryBody")
|
|
if ctx.transformClosureIteratorBody(tryBody, outToFinally) != tryBody:
|
|
internalError(ctx.g.config, "transformClosureIteratorBody != tryBody")
|
|
|
|
ctx.curExcHandlingState = finallyIdx
|
|
ctx.addElseToExcept(exceptBody)
|
|
if ctx.transformReturnsInTry(exceptBody) != exceptBody:
|
|
internalError(ctx.g.config, "transformReturnsInTry != exceptBody")
|
|
if ctx.transformClosureIteratorBody(exceptBody, outToFinally) != exceptBody:
|
|
internalError(ctx.g.config, "transformClosureIteratorBody != exceptBody")
|
|
|
|
ctx.curExcHandlingState = oldExcHandlingState
|
|
ctx.nearestFinally = oldNearestFinally
|
|
if ctx.transformClosureIteratorBody(finallyBody, gotoOut) != finallyBody:
|
|
internalError(ctx.g.config, "transformClosureIteratorBody != finallyBody")
|
|
|
|
of nkGotoState, nkForStmt:
|
|
internalError(ctx.g.config, "closure iter " & $n.kind)
|
|
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformClosureIteratorBody(n[i], gotoOut)
|
|
|
|
proc stateFromGotoState(n: PNode): int =
|
|
assert(n.kind == nkGotoState)
|
|
result = n[0].intVal.int
|
|
|
|
proc transformStateAssignments(ctx: var Ctx, n: PNode): PNode =
|
|
# This transforms 3 patterns:
|
|
########################## 1
|
|
# yield e
|
|
# goto STATE
|
|
# ->
|
|
# :state = STATE
|
|
# return e
|
|
########################## 2
|
|
# goto STATE
|
|
# ->
|
|
# :state = STATE
|
|
# break :stateLoop
|
|
########################## 3
|
|
# return e
|
|
# ->
|
|
# :state = -1
|
|
# return e
|
|
#
|
|
result = n
|
|
case n.kind
|
|
of nkStmtList, nkStmtListExpr:
|
|
if n.len != 0 and n[0].kind == nkYieldStmt:
|
|
assert(n.len == 2)
|
|
assert(n[1].kind == nkGotoState)
|
|
|
|
result = newNodeI(nkStmtList, n.info)
|
|
result.add(ctx.newStateAssgn(stateFromGotoState(n[1])))
|
|
|
|
var retStmt = newNodeI(nkReturnStmt, n.info)
|
|
if n[0][0].kind != nkEmpty:
|
|
var a = newNodeI(nkAsgn, n[0][0].info)
|
|
var retVal = n[0][0] #liftCapturedVars(n[0], owner, d, c)
|
|
a.add newSymNode(getClosureIterResult(ctx.g, ctx.fn, ctx.idgen))
|
|
a.add retVal
|
|
retStmt.add(a)
|
|
else:
|
|
retStmt.add(ctx.g.emptyNode)
|
|
|
|
result.add(retStmt)
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformStateAssignments(n[i])
|
|
|
|
of nkSkip:
|
|
discard
|
|
|
|
of nkReturnStmt:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
result.add(ctx.newStateAssgn(-1))
|
|
result.add(n)
|
|
|
|
of nkGotoState:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
result.add(ctx.newStateAssgn(stateFromGotoState(n)))
|
|
|
|
let breakState = newNodeI(nkBreakStmt, n.info)
|
|
breakState.add(newSymNode(ctx.stateLoopLabel))
|
|
result.add(breakState)
|
|
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.transformStateAssignments(n[i])
|
|
|
|
proc skipStmtList(ctx: Ctx; n: PNode): PNode =
|
|
result = n
|
|
while result.kind in {nkStmtList}:
|
|
if result.len == 0: return ctx.g.emptyNode
|
|
result = result[0]
|
|
|
|
proc skipEmptyStates(ctx: Ctx, stateIdx: int): int =
|
|
# Returns first non-empty state idx for `stateIdx`. Returns `stateIdx` if
|
|
# it is not empty
|
|
var maxJumps = ctx.states.len # maxJumps used only for debugging purposes.
|
|
var stateIdx = stateIdx
|
|
while true:
|
|
let label = stateIdx
|
|
if label == ctx.exitStateIdx: break
|
|
var newLabel = label
|
|
if label == emptyStateLabel:
|
|
newLabel = ctx.exitStateIdx
|
|
else:
|
|
let fs = skipStmtList(ctx, ctx.states[label].body)
|
|
if fs.kind == nkGotoState:
|
|
newLabel = fs[0].intVal.int
|
|
if label == newLabel: break
|
|
stateIdx = newLabel
|
|
dec maxJumps
|
|
if maxJumps == 0:
|
|
assert(false, "Internal error")
|
|
|
|
result = ctx.states[stateIdx].label
|
|
|
|
proc skipThroughEmptyStates(ctx: var Ctx, n: PNode): PNode=
|
|
result = n
|
|
case n.kind
|
|
of nkSkip:
|
|
discard
|
|
of nkGotoState:
|
|
result = copyTree(n)
|
|
result[0].intVal = ctx.skipEmptyStates(result[0].intVal.int)
|
|
else:
|
|
for i in 0..<n.len:
|
|
n[i] = ctx.skipThroughEmptyStates(n[i])
|
|
|
|
proc newArrayType(g: ModuleGraph; n: int, t: PType; idgen: IdGenerator; owner: PSym): PType =
|
|
result = newType(tyArray, idgen, owner)
|
|
|
|
let rng = newType(tyRange, idgen, owner)
|
|
rng.n = newTree(nkRange, g.newIntLit(owner.info, 0), g.newIntLit(owner.info, n - 1))
|
|
rng.rawAddSon(t)
|
|
|
|
result.rawAddSon(rng)
|
|
result.rawAddSon(t)
|
|
|
|
proc createExceptionTable(ctx: var Ctx): PNode {.inline.} =
|
|
result = newNodeI(nkBracket, ctx.fn.info)
|
|
result.typ = ctx.g.newArrayType(ctx.exceptionTable.len, ctx.g.getSysType(ctx.fn.info, tyInt16), ctx.idgen, ctx.fn)
|
|
|
|
for i in ctx.exceptionTable:
|
|
let elem = newIntNode(nkIntLit, i)
|
|
elem.typ = ctx.g.getSysType(ctx.fn.info, tyInt16)
|
|
result.add(elem)
|
|
|
|
proc newCatchBody(ctx: var Ctx, info: TLineInfo): PNode {.inline.} =
|
|
# Generates the code:
|
|
# :state = exceptionTable[:state]
|
|
# if :state == 0: raise
|
|
# :unrollFinally = :state > 0
|
|
# if :state < 0:
|
|
# :state = -:state
|
|
# :curExc = getCurrentException()
|
|
|
|
result = newNodeI(nkStmtList, info)
|
|
|
|
let intTyp = ctx.g.getSysType(info, tyInt)
|
|
let boolTyp = ctx.g.getSysType(info, tyBool)
|
|
|
|
# :state = exceptionTable[:state]
|
|
block:
|
|
# exceptionTable[:state]
|
|
let getNextState = newTree(nkBracketExpr,
|
|
ctx.createExceptionTable(),
|
|
ctx.newStateAccess())
|
|
getNextState.typ = intTyp
|
|
|
|
# :state = exceptionTable[:state]
|
|
result.add(ctx.newStateAssgn(getNextState))
|
|
|
|
# if :state == 0: raise
|
|
block:
|
|
let cond = newTree(nkCall,
|
|
ctx.g.getSysMagic(info, "==", mEqI).newSymNode(),
|
|
ctx.newStateAccess(),
|
|
newIntTypeNode(0, intTyp))
|
|
cond.typ = boolTyp
|
|
|
|
let raiseStmt = newTree(nkRaiseStmt, ctx.g.emptyNode)
|
|
let ifBranch = newTree(nkElifBranch, cond, raiseStmt)
|
|
let ifStmt = newTree(nkIfStmt, ifBranch)
|
|
result.add(ifStmt)
|
|
|
|
# :unrollFinally = :state > 0
|
|
block:
|
|
let cond = newTree(nkCall,
|
|
ctx.g.getSysMagic(info, "<", mLtI).newSymNode,
|
|
newIntTypeNode(0, intTyp),
|
|
ctx.newStateAccess())
|
|
cond.typ = boolTyp
|
|
|
|
let asgn = newTree(nkAsgn, ctx.newUnrollFinallyAccess(info), cond)
|
|
result.add(asgn)
|
|
|
|
# if :state < 0: :state = -:state
|
|
block:
|
|
let cond = newTree(nkCall,
|
|
ctx.g.getSysMagic(info, "<", mLtI).newSymNode,
|
|
ctx.newStateAccess(),
|
|
newIntTypeNode(0, intTyp))
|
|
cond.typ = boolTyp
|
|
|
|
let negateState = newTree(nkCall,
|
|
ctx.g.getSysMagic(info, "-", mUnaryMinusI).newSymNode,
|
|
ctx.newStateAccess())
|
|
negateState.typ = intTyp
|
|
|
|
let ifBranch = newTree(nkElifBranch, cond, ctx.newStateAssgn(negateState))
|
|
let ifStmt = newTree(nkIfStmt, ifBranch)
|
|
result.add(ifStmt)
|
|
|
|
# :curExc = getCurrentException()
|
|
block:
|
|
result.add(newTree(nkAsgn,
|
|
ctx.newCurExcAccess(),
|
|
ctx.g.callCodegenProc("getCurrentException")))
|
|
|
|
proc wrapIntoTryExcept(ctx: var Ctx, n: PNode): PNode {.inline.} =
|
|
let setupExc = newTree(nkCall,
|
|
newSymNode(ctx.g.getCompilerProc("closureIterSetupExc")),
|
|
ctx.newCurExcAccess())
|
|
|
|
let tryBody = newTree(nkStmtList, setupExc, n)
|
|
let exceptBranch = newTree(nkExceptBranch, ctx.newCatchBody(ctx.fn.info))
|
|
|
|
result = newTree(nkTryStmt, tryBody, exceptBranch)
|
|
|
|
proc wrapIntoStateLoop(ctx: var Ctx, n: PNode): PNode =
|
|
# while true:
|
|
# block :stateLoop:
|
|
# local vars decl (if needed)
|
|
# body # Might get wrapped in try-except
|
|
let loopBody = newNodeI(nkStmtList, n.info)
|
|
result = newTree(nkWhileStmt, ctx.g.boolLit(n.info, true), loopBody)
|
|
result.info = n.info
|
|
|
|
let localVars = newNodeI(nkStmtList, n.info)
|
|
|
|
let blockStmt = newNodeI(nkBlockStmt, n.info)
|
|
blockStmt.add(newSymNode(ctx.stateLoopLabel))
|
|
|
|
var blockBody = newTree(nkStmtList, localVars, n)
|
|
if ctx.hasExceptions:
|
|
blockBody = ctx.wrapIntoTryExcept(blockBody)
|
|
|
|
blockStmt.add(blockBody)
|
|
loopBody.add(blockStmt)
|
|
|
|
proc deleteEmptyStates(ctx: var Ctx) =
|
|
let goOut = newTree(nkGotoState, ctx.g.newIntLit(TLineInfo(), -1))
|
|
ctx.exitStateIdx = ctx.newState(goOut, nil)
|
|
|
|
# Apply new state indexes and mark unused states with -1
|
|
var iValid = 0
|
|
for i, s in ctx.states.mpairs:
|
|
let body = skipStmtList(ctx, s.body)
|
|
if body.kind == nkGotoState and i != ctx.states.len - 1 and i != 0:
|
|
# This is an empty state. Mark with -1.
|
|
s.label = emptyStateLabel
|
|
else:
|
|
s.label = iValid
|
|
inc iValid
|
|
|
|
for i, s in ctx.states:
|
|
let body = skipStmtList(ctx, s.body)
|
|
if body.kind != nkGotoState or i == 0:
|
|
discard ctx.skipThroughEmptyStates(s.body)
|
|
let excHandlState = ctx.exceptionTable[i]
|
|
if excHandlState < 0:
|
|
ctx.exceptionTable[i] = -ctx.skipEmptyStates(-excHandlState)
|
|
elif excHandlState != 0:
|
|
ctx.exceptionTable[i] = ctx.skipEmptyStates(excHandlState)
|
|
|
|
var i = 1 # ignore the entry and the exit
|
|
while i < ctx.states.len - 1:
|
|
if ctx.states[i].label == emptyStateLabel:
|
|
ctx.states.delete(i)
|
|
ctx.exceptionTable.delete(i)
|
|
else:
|
|
inc i
|
|
|
|
type
|
|
PreprocessContext = object
|
|
finallys: seq[PNode]
|
|
config: ConfigRef
|
|
blocks: seq[(PNode, int)]
|
|
idgen: IdGenerator
|
|
FreshVarsContext = object
|
|
tab: Table[int, PSym]
|
|
config: ConfigRef
|
|
info: TLineInfo
|
|
idgen: IdGenerator
|
|
|
|
proc freshVars(n: PNode; c: var FreshVarsContext): PNode =
|
|
case n.kind
|
|
of nkSym:
|
|
let x = c.tab.getOrDefault(n.sym.id)
|
|
if x == nil:
|
|
result = n
|
|
else:
|
|
result = newSymNode(x, n.info)
|
|
of nkSkip - {nkSym}:
|
|
result = n
|
|
of nkLetSection, nkVarSection:
|
|
result = copyNode(n)
|
|
for it in n:
|
|
if it.kind in {nkIdentDefs, nkVarTuple}:
|
|
let idefs = copyNode(it)
|
|
for v in 0..it.len-3:
|
|
if it[v].kind == nkSym:
|
|
let x = copySym(it[v].sym, c.idgen)
|
|
c.tab[it[v].sym.id] = x
|
|
idefs.add newSymNode(x)
|
|
else:
|
|
idefs.add it[v]
|
|
|
|
for rest in it.len-2 ..< it.len: idefs.add it[rest]
|
|
result.add idefs
|
|
else:
|
|
result.add it
|
|
of nkRaiseStmt:
|
|
result = nil
|
|
localError(c.config, c.info, "unsupported control flow: 'finally: ... raise' duplicated because of 'break'")
|
|
else:
|
|
result = n
|
|
for i in 0..<n.safeLen:
|
|
result[i] = freshVars(n[i], c)
|
|
|
|
proc preprocess(c: var PreprocessContext; n: PNode): PNode =
|
|
# in order to fix bug #15243 without risking regressions, we preprocess
|
|
# the AST so that 'break' statements inside a 'try finally' also have the
|
|
# finally section. We need to duplicate local variables here and also
|
|
# detect: 'finally: raises X' which is currently not supported. We produce
|
|
# an error for this case for now. All this will be done properly with Yuriy's
|
|
# patch.
|
|
|
|
result = n
|
|
case n.kind
|
|
of nkTryStmt:
|
|
let f = n.lastSon
|
|
var didAddSomething = false
|
|
if f.kind == nkFinally:
|
|
c.finallys.add f.lastSon
|
|
didAddSomething = true
|
|
|
|
for i in 0 ..< n.len:
|
|
result[i] = preprocess(c, n[i])
|
|
|
|
if didAddSomething:
|
|
discard c.finallys.pop()
|
|
|
|
of nkWhileStmt, nkBlockStmt:
|
|
if not n.hasYields: return n
|
|
c.blocks.add((n, c.finallys.len))
|
|
for i in 0 ..< n.len:
|
|
result[i] = preprocess(c, n[i])
|
|
discard c.blocks.pop()
|
|
|
|
of nkBreakStmt:
|
|
if c.blocks.len == 0:
|
|
discard
|
|
else:
|
|
var fin = -1
|
|
if n[0].kind == nkEmpty:
|
|
fin = c.blocks[^1][1]
|
|
elif n[0].kind == nkSym:
|
|
for i in countdown(c.blocks.high, 0):
|
|
if c.blocks[i][0].kind == nkBlockStmt and c.blocks[i][0][0].kind == nkSym and
|
|
c.blocks[i][0][0].sym == n[0].sym:
|
|
fin = c.blocks[i][1]
|
|
break
|
|
|
|
if fin >= 0:
|
|
result = newNodeI(nkStmtList, n.info)
|
|
for i in countdown(c.finallys.high, fin):
|
|
var vars = FreshVarsContext(tab: initTable[int, PSym](), config: c.config, info: n.info, idgen: c.idgen)
|
|
result.add freshVars(copyTree(c.finallys[i]), vars)
|
|
c.idgen = vars.idgen
|
|
result.add n
|
|
of nkSkip: discard
|
|
else:
|
|
for i in 0 ..< n.len:
|
|
result[i] = preprocess(c, n[i])
|
|
|
|
proc detectCapturedVars(c: var Ctx, n: PNode, stateIdx: int) =
|
|
case n.kind
|
|
of nkSym:
|
|
let s = n.sym
|
|
if s.kind in {skResult, skVar, skLet, skForVar, skTemp} and sfGlobal notin s.flags and s.owner == c.fn:
|
|
let vs = c.varStates.getOrDefault(s.itemId, localNotSeen)
|
|
if vs == localNotSeen: # First seing this variable
|
|
c.varStates[s.itemId] = stateIdx
|
|
elif vs == localRequiresLifting:
|
|
discard # Sym already marked
|
|
elif vs != stateIdx:
|
|
c.captureVar(s)
|
|
of nkReturnStmt:
|
|
if n[0].kind in {nkAsgn, nkFastAsgn, nkSinkAsgn}:
|
|
# we have a `result = result` expression produced by the closure
|
|
# transform, let's not touch the LHS in order to make the lifting pass
|
|
# correct when `result` is lifted
|
|
detectCapturedVars(c, n[0][1], stateIdx)
|
|
else:
|
|
detectCapturedVars(c, n[0], stateIdx)
|
|
else:
|
|
for i in 0 ..< n.safeLen:
|
|
detectCapturedVars(c, n[i], stateIdx)
|
|
|
|
proc detectCapturedVars(c: var Ctx) =
|
|
for i, s in c.states:
|
|
detectCapturedVars(c, s.body, i)
|
|
|
|
proc liftLocals(c: var Ctx, n: PNode): PNode =
|
|
result = n
|
|
case n.kind
|
|
of nkSym:
|
|
let s = n.sym
|
|
if c.varStates.getOrDefault(s.itemId) == localRequiresLifting:
|
|
# lift
|
|
let e = getEnvParam(c.fn)
|
|
let field = getFieldFromObj(e.typ.elementType, s)
|
|
assert(field != nil)
|
|
result = rawIndirectAccess(newSymNode(e), field, n.info)
|
|
# elif c.varStates.getOrDefault(s.itemId, localNotSeen) != localNotSeen:
|
|
# echo "Not lifting ", s.name.s
|
|
|
|
of nkReturnStmt:
|
|
if n[0].kind in {nkAsgn, nkFastAsgn, nkSinkAsgn}:
|
|
# we have a `result = result` expression produced by the closure
|
|
# transform, let's not touch the LHS in order to make the lifting pass
|
|
# correct when `result` is lifted
|
|
n[0][1] = liftLocals(c, n[0][1])
|
|
else:
|
|
n[0] = liftLocals(c, n[0])
|
|
else:
|
|
for i in 0 ..< n.safeLen:
|
|
n[i] = liftLocals(c, n[i])
|
|
|
|
proc transformClosureIterator*(g: ModuleGraph; idgen: IdGenerator; fn: PSym, n: PNode): PNode =
|
|
var ctx = Ctx(g: g, fn: fn, idgen: idgen)
|
|
|
|
# The transformation should always happen after at least partial lambdalifting
|
|
# is performed, so that the closure iter environment is always created upfront.
|
|
doAssert(getEnvParam(fn) != nil, "Env param not created before iter transformation")
|
|
|
|
ctx.stateLoopLabel = newSym(skLabel, getIdent(ctx.g.cache, ":stateLoop"), idgen, fn, fn.info)
|
|
var pc = PreprocessContext(finallys: @[], config: g.config, idgen: idgen)
|
|
var n = preprocess(pc, n.toStmtList)
|
|
#echo "transformed into ", n
|
|
#var n = n.toStmtList
|
|
|
|
discard ctx.newState(n, nil)
|
|
let gotoOut = newTree(nkGotoState, g.newIntLit(n.info, -1))
|
|
|
|
var ns = false
|
|
n = ctx.lowerStmtListExprs(n, ns)
|
|
|
|
if n.hasYieldsInExpressions():
|
|
internalError(ctx.g.config, "yield in expr not lowered")
|
|
|
|
# Splitting transformation
|
|
discard ctx.transformClosureIteratorBody(n, gotoOut)
|
|
|
|
# Optimize empty states away
|
|
ctx.deleteEmptyStates()
|
|
|
|
let caseDispatcher = newTreeI(nkCaseStmt, n.info,
|
|
ctx.newStateAccess())
|
|
|
|
# Lamdalifting will not touch our locals, it is our responsibility to lift those that
|
|
# need it.
|
|
detectCapturedVars(ctx)
|
|
|
|
for s in ctx.states:
|
|
let body = ctx.transformStateAssignments(s.body)
|
|
caseDispatcher.add newTreeI(nkOfBranch, body.info, g.newIntLit(body.info, s.label), body)
|
|
|
|
caseDispatcher.add newTreeI(nkElse, n.info, newTreeI(nkReturnStmt, n.info, g.emptyNode))
|
|
|
|
result = wrapIntoStateLoop(ctx, caseDispatcher)
|
|
result = liftLocals(ctx, result)
|
|
|
|
when false:
|
|
echo "TRANSFORM TO STATES: "
|
|
echo renderTree(result)
|
|
|
|
echo "exception table:"
|
|
for i, e in ctx.exceptionTable:
|
|
echo i, " -> ", e
|
|
|
|
echo "ENV: ", renderTree(getEnvParam(fn).typ.elementType.n)
|