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ccgstmts.nim
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#
#
# The Nim Compiler
# (c) Copyright 2015 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
# included from cgen.nim
const
RangeExpandLimit = 256 # do not generate ranges
# over 'RangeExpandLimit' elements
stringCaseThreshold = 8
# above X strings a hash-switch for strings is generated
proc registerTraverseProc(p: BProc, v: PSym) =
var traverseProc = ""
if p.config.selectedGC in {gcMarkAndSweep, gcHooks, gcRefc} and
optOwnedRefs notin p.config.globalOptions and
containsGarbageCollectedRef(v.loc.t):
# we register a specialized marked proc here; this has the advantage
# that it works out of the box for thread local storage then :-)
traverseProc = genTraverseProcForGlobal(p.module, v, v.info)
if traverseProc.len != 0 and not p.hcrOn:
p.module.preInitProc.procSec(cpsInit).add("\n\t")
let fnName = cgsymValue(p.module,
if sfThread in v.flags: "nimRegisterThreadLocalMarker"
else: "nimRegisterGlobalMarker")
p.module.preInitProc.procSec(cpsInit).addCallStmt(fnName, traverseProc)
p.module.preInitProc.procSec(cpsInit).add("\n")
proc isAssignedImmediately(conf: ConfigRef; n: PNode): bool {.inline.} =
if n.kind == nkEmpty:
result = false
elif n.kind in nkCallKinds and n[0] != nil and n[0].typ != nil and n[0].typ.skipTypes(abstractInst).kind == tyProc:
if n[0].kind == nkSym and sfConstructor in n[0].sym.flags:
result = true
elif isInvalidReturnType(conf, n[0].typ, true):
# var v = f()
# is transformed into: var v; f(addr v)
# where 'f' **does not** initialize the result!
result = false
else:
result = true
elif isInvalidReturnType(conf, n.typ, false):
result = false
else:
result = true
proc inExceptBlockLen(p: BProc): int =
result = 0
for x in p.nestedTryStmts:
if x.inExcept: result.inc
proc startBlockInside(p: BProc): int {.discardable.} =
inc(p.labels)
result = p.blocks.len
p.blocks.add initBlock()
p.blocks[result].id = p.labels
p.blocks[result].nestedTryStmts = p.nestedTryStmts.len.int16
p.blocks[result].nestedExceptStmts = p.inExceptBlockLen.int16
template startBlockWith(p: BProc, body: typed): int =
body
startBlockInside(p)
proc blockBody(b: var TBlock; result: var Builder) =
result.add extract(b.sections[cpsLocals])
if b.frameLen > 0:
result.addInPlaceOp(Add, NimInt, dotField("FR_", "len"), cIntValue(b.frameLen.int))
result.add(extract(b.sections[cpsInit]))
result.add(extract(b.sections[cpsStmts]))
if b.frameLen > 0:
result.addInPlaceOp(Sub, NimInt, dotField("FR_", "len"), cIntValue(b.frameLen.int))
proc endBlockInside(p: BProc) =
let topBlock = p.blocks.len-1
# the block is merged into the parent block
p.blocks[topBlock].blockBody(p.blocks[topBlock-1].sections[cpsStmts])
setLen(p.blocks, topBlock)
proc endBlockOutside(p: BProc, label: TLabel) =
if label.len != 0:
let topBlock = p.blocks.len - 1
p.blocks[topBlock].sections[cpsStmts].addLabel(label)
template endBlockWith(p: BProc, body: typed) =
let label = p.blocks[p.blocks.len - 1].label
endBlockInside(p)
body
endBlockOutside(p, label)
proc genVarTuple(p: BProc, n: PNode) =
if n.kind != nkVarTuple: internalError(p.config, n.info, "genVarTuple")
# if we have a something that's been captured, use the lowering instead:
for i in 0..<n.len-2:
if n[i].kind != nkSym:
genStmts(p, lowerTupleUnpacking(p.module.g.graph, n, p.module.idgen, p.prc))
return
# check only the first son
var forHcr = treatGlobalDifferentlyForHCR(p.module, n[0].sym)
let hcrCond = if forHcr: getTempName(p.module) else: ""
var hcrGlobals: seq[tuple[loc: TLoc, tp: Rope]] = @[]
# determine if the tuple is constructed at top-level scope or inside of a block (if/while/block)
let isGlobalInBlock = forHcr and p.blocks.len > 2
# do not close and reopen blocks if this is a 'global' but inside of a block (if/while/block)
forHcr = forHcr and not isGlobalInBlock
var hcrIf = default(IfBuilder)
if forHcr:
startBlockWith(p):
# check with the boolean if the initializing code for the tuple should be ran
hcrIf = initIfStmt(p.s(cpsStmts))
initElifBranch(p.s(cpsStmts), hcrIf, hcrCond)
genLineDir(p, n)
var tup = initLocExpr(p, n[^1])
var t = tup.t.skipTypes(abstractInst)
for i in 0..<n.len-2:
let vn = n[i]
let v = vn.sym
if sfCompileTime in v.flags: continue
if sfGlobal in v.flags:
assignGlobalVar(p, vn, "")
genObjectInit(p, cpsInit, v.typ, v.loc, constructObj)
registerTraverseProc(p, v)
else:
assignLocalVar(p, vn)
initLocalVar(p, v, immediateAsgn=isAssignedImmediately(p.config, n[^1]))
var field = initLoc(locExpr, vn, tup.storage)
let rtup = rdLoc(tup)
let fieldName =
if t.kind == tyTuple:
"Field" & $i
else:
if t.n[i].kind != nkSym: internalError(p.config, n.info, "genVarTuple")
mangleRecFieldName(p.module, t.n[i].sym)
field.snippet = dotField(rtup, fieldName)
putLocIntoDest(p, v.loc, field)
if forHcr or isGlobalInBlock:
hcrGlobals.add((loc: v.loc, tp: CNil))
if forHcr:
# end the block where the tuple gets initialized
endBlockWith(p):
finishBranch(p.s(cpsStmts), hcrIf)
finishIfStmt(p.s(cpsStmts), hcrIf)
if forHcr or isGlobalInBlock:
# insert the registration of the globals for the different parts of the tuple at the
# start of the current scope (after they have been iterated) and init a boolean to
# check if any of them is newly introduced and the initializing code has to be ran
p.s(cpsLocals).addVar(kind = Local,
name = hcrCond,
typ = NimBool,
initializer = NimFalse)
for curr in hcrGlobals:
let rc = rdLoc(curr.loc)
p.s(cpsLocals).addInPlaceOp(BitOr, NimBool,
hcrCond,
cCall("hcrRegisterGlobal",
getModuleDllPath(p.module, n[0].sym),
'"' & curr.loc.snippet & '"',
cSizeof(rc),
curr.tp,
cCast(ptrType(CPointer), cAddr(curr.loc.snippet))))
proc loadInto(p: BProc, le, ri: PNode, a: var TLoc) {.inline.} =
if ri.kind in nkCallKinds and (ri[0].kind != nkSym or
ri[0].sym.magic == mNone):
genAsgnCall(p, le, ri, a)
else:
# this is a hacky way to fix #1181 (tmissingderef)::
#
# var arr1 = cast[ptr array[4, int8]](addr foo)[]
#
# However, fixing this properly really requires modelling 'array' as
# a 'struct' in C to preserve dereferencing semantics completely. Not
# worth the effort until version 1.0 is out.
a.flags.incl(lfEnforceDeref)
expr(p, ri, a)
proc assignLabel(b: var TBlock; result: var TLabel) {.inline.} =
b.label = "LA" & b.id.rope
result = b.label
proc startSimpleBlock(p: BProc, scope: out ScopeBuilder): int {.discardable, inline.} =
startBlockWith(p):
scope = initScope(p.s(cpsStmts))
proc endSimpleBlock(p: BProc, scope: var ScopeBuilder) {.inline.} =
endBlockWith(p):
finishScope(p.s(cpsStmts), scope)
proc genSimpleBlock(p: BProc, stmts: PNode) {.inline.} =
var scope: ScopeBuilder
startSimpleBlock(p, scope)
genStmts(p, stmts)
endSimpleBlock(p, scope)
proc exprBlock(p: BProc, n: PNode, d: var TLoc) =
var scope: ScopeBuilder
startSimpleBlock(p, scope)
expr(p, n, d)
endSimpleBlock(p, scope)
template preserveBreakIdx(body: untyped): untyped =
var oldBreakIdx = p.breakIdx
body
p.breakIdx = oldBreakIdx
proc genState(p: BProc, n: PNode) =
internalAssert p.config, n.len == 1
let n0 = n[0]
if n0.kind == nkIntLit:
let idx = n[0].intVal
p.s(cpsStmts).addLabel("STATE" & $idx)
elif n0.kind == nkStrLit:
p.s(cpsStmts).addLabel(n0.strVal)
proc blockLeaveActions(p: BProc, howManyTrys, howManyExcepts: int) =
# Called by return and break stmts.
# Deals with issues faced when jumping out of try/except/finally stmts.
var stack = newSeq[tuple[fin: PNode, inExcept: bool, label: Natural]](0)
inc p.withinBlockLeaveActions
for i in 1..howManyTrys:
let tryStmt = p.nestedTryStmts.pop
if p.config.exc == excSetjmp:
# Pop safe points generated by try
if not tryStmt.inExcept:
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "popSafePoint"))
# Pop this try-stmt of the list of nested trys
# so we don't infinite recurse on it in the next step.
stack.add(tryStmt)
# Find finally-stmt for this try-stmt
# and generate a copy of its sons
var finallyStmt = tryStmt.fin
if finallyStmt != nil:
genStmts(p, finallyStmt[0])
dec p.withinBlockLeaveActions
# push old elements again:
for i in countdown(howManyTrys-1, 0):
p.nestedTryStmts.add(stack[i])
# Pop exceptions that was handled by the
# except-blocks we are in
if noSafePoints notin p.flags:
for i in countdown(howManyExcepts-1, 0):
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "popCurrentException"))
proc genGotoState(p: BProc, n: PNode) =
# we resist the temptation to translate it into duff's device as it later
# will be translated into computed gotos anyway for GCC at least:
# switch (x.state) {
# case 0: goto STATE0;
# ...
var a: TLoc = initLocExpr(p, n[0])
let ra = rdLoc(a)
p.s(cpsStmts).addSwitchStmt(ra):
p.flags.incl beforeRetNeeded
p.s(cpsStmts).addSingleSwitchCase(cIntValue(-1)):
blockLeaveActions(p,
howManyTrys = p.nestedTryStmts.len,
howManyExcepts = p.inExceptBlockLen)
p.s(cpsStmts).addGoto("BeforeRet_")
var statesCounter = lastOrd(p.config, n[0].typ)
if n.len >= 2 and n[1].kind == nkIntLit:
statesCounter = getInt(n[1])
let prefix = if n.len == 3 and n[2].kind == nkStrLit: n[2].strVal.rope
else: rope"STATE"
for i in 0i64..toInt64(statesCounter):
p.s(cpsStmts).addSingleSwitchCase(cIntValue(i)):
p.s(cpsStmts).addGoto(prefix & $i)
proc genBreakState(p: BProc, n: PNode, d: var TLoc) =
var a: TLoc
d = initLoc(locExpr, n, OnUnknown)
if n[0].kind == nkClosure:
a = initLocExpr(p, n[0][1])
let ra = a.rdLoc
d.snippet = cOp(LessThan,
subscript(
cCast(ptrType(NimInt), ra),
cIntValue(1)),
cIntValue(0))
else:
a = initLocExpr(p, n[0])
let ra = a.rdLoc
# the environment is guaranteed to contain the 'state' field at offset 1:
d.snippet = cOp(LessThan,
subscript(
cCast(ptrType(NimInt), dotField(ra, "ClE_0")),
cIntValue(1)),
cIntValue(0))
proc genGotoVar(p: BProc; value: PNode) =
if value.kind notin {nkCharLit..nkUInt64Lit}:
localError(p.config, value.info, "'goto' target must be a literal value")
else:
p.s(cpsStmts).addGoto("NIMSTATE_" & $value.intVal)
proc genBracedInit(p: BProc, n: PNode; isConst: bool; optionalType: PType; result: var Builder)
proc potentialValueInit(p: BProc; v: PSym; value: PNode; result: var Builder) =
if lfDynamicLib in v.loc.flags or sfThread in v.flags or p.hcrOn:
discard "nothing to do"
elif sfGlobal in v.flags and value != nil and isDeepConstExpr(value, p.module.compileToCpp) and
p.withinLoop == 0 and not containsGarbageCollectedRef(v.typ):
#echo "New code produced for ", v.name.s, " ", p.config $ value.info
genBracedInit(p, value, isConst = false, v.typ, result)
proc genCppParamsForCtor(p: BProc; call: PNode; didGenTemp: var bool): Snippet =
var res = newBuilder("")
var argBuilder = default(CallBuilder) # not init, only building params
let typ = skipTypes(call[0].typ, abstractInst)
assert(typ.kind == tyProc)
for i in 1..<call.len:
#if it's a type we can just generate here another initializer as we are in an initializer context
if call[i].kind == nkCall and call[i][0].kind == nkSym and call[i][0].sym.kind == skType:
res.addArgument(argBuilder):
res.add genCppInitializer(p.module, p, call[i][0].sym.typ, didGenTemp)
else:
#We need to test for temp in globals, see: #23657
let param =
if typ[i].kind in {tyVar} and call[i].kind == nkHiddenAddr:
call[i][0]
else:
call[i]
if param.kind != nkBracketExpr or param.typ.kind in
{tyRef, tyPtr, tyUncheckedArray, tyArray, tyOpenArray,
tyVarargs, tySequence, tyString, tyCstring, tyTuple}:
let tempLoc = initLocExprSingleUse(p, param)
didGenTemp = didGenTemp or tempLoc.k == locTemp
genOtherArg(p, call, i, typ, res, argBuilder)
result = extract(res)
proc genSingleVar(p: BProc, v: PSym; vn, value: PNode) =
if sfGoto in v.flags:
# translate 'var state {.goto.} = X' into 'goto LX':
genGotoVar(p, value)
return
let imm = isAssignedImmediately(p.config, value)
let isCppCtorCall = p.module.compileToCpp and imm and
value.kind in nkCallKinds and value[0].kind == nkSym and
v.typ.kind != tyPtr and sfConstructor in value[0].sym.flags
var targetProc = p
var valueBuilder = newBuilder("")
potentialValueInit(p, v, value, valueBuilder)
let valueAsRope = extract(valueBuilder)
if sfGlobal in v.flags:
if v.flags * {sfImportc, sfExportc} == {sfImportc} and
value.kind == nkEmpty and
v.loc.flags * {lfHeader, lfNoDecl} != {}:
return
if sfPure in v.flags:
# v.owner.kind != skModule:
targetProc = p.module.preInitProc
if isCppCtorCall and not containsHiddenPointer(v.typ):
var didGenTemp = false
callGlobalVarCppCtor(targetProc, v, vn, value, didGenTemp)
if didGenTemp:
message(p.config, vn.info, warnGlobalVarConstructorTemporary, vn.sym.name.s)
#We fail to call the constructor in the global scope so we do the call inside the main proc
assignGlobalVar(targetProc, vn, valueAsRope)
var loc = initLocExprSingleUse(targetProc, value)
genAssignment(targetProc, v.loc, loc, {})
else:
assignGlobalVar(targetProc, vn, valueAsRope)
# XXX: be careful here.
# Global variables should not be zeromem-ed within loops
# (see bug #20).
# That's why we are doing the construction inside the preInitProc.
# genObjectInit relies on the C runtime's guarantees that
# global variables will be initialized to zero.
if valueAsRope.len == 0:
var loc = v.loc
# When the native TLS is unavailable, a global thread-local variable needs
# one more layer of indirection in order to access the TLS block.
# Only do this for complex types that may need a call to `objectInit`
if sfThread in v.flags and emulatedThreadVars(p.config) and
isComplexValueType(v.typ):
loc = initLocExprSingleUse(p.module.preInitProc, vn)
genObjectInit(p.module.preInitProc, cpsInit, v.typ, loc, constructObj)
# Alternative construction using default constructor (which may zeromem):
# if sfImportc notin v.flags: constructLoc(p.module.preInitProc, v.loc)
if sfExportc in v.flags and p.module.g.generatedHeader != nil:
genVarPrototype(p.module.g.generatedHeader, vn)
registerTraverseProc(p, v)
else:
if imm and p.module.compileToCpp and p.splitDecls == 0 and
not containsHiddenPointer(v.typ) and
nimErrorFlagAccessed notin p.flags:
# C++ really doesn't like things like 'Foo f; f = x' as that invokes a
# parameterless constructor followed by an assignment operator. So we
# generate better code here: 'Foo f = x;'
genLineDir(p, vn)
var initializer: Snippet = ""
var initializerKind: VarInitializerKind = Assignment
if isCppCtorCall:
var didGenTemp = false
initializer = genCppParamsForCtor(p, value, didGenTemp)
if initializer.len != 0:
initializer = "(" & initializer & ")"
initializerKind = CppConstructor
else:
var tmp = initLocExprSingleUse(p, value)
if value.kind != nkEmpty:
initializer = tmp.rdLoc
localVarDecl(p.s(cpsStmts), p, vn, initializer, initializerKind)
return
assignLocalVar(p, vn)
initLocalVar(p, v, imm)
let traverseProc = CNil
# If the var is in a block (control flow like if/while or a block) in global scope just
# register the so called "global" so it can be used later on. There is no need to close
# and reopen of if (nim_hcr_do_init_) blocks because we are in one already anyway.
var forHcr = treatGlobalDifferentlyForHCR(p.module, v)
if forHcr and targetProc.blocks.len > 3 and v.owner.kind == skModule:
# put it in the locals section - mainly because of loops which
# use the var in a call to resetLoc() in the statements section
let rv = rdLoc(v.loc)
p.s(cpsLocals).addCallStmt("hcrRegisterGlobal",
getModuleDllPath(p.module, v),
'"' & v.loc.snippet & '"',
cSizeof(rv),
traverseProc,
cCast(ptrType(CPointer), cAddr(v.loc.snippet)))
# nothing special left to do later on - let's avoid closing and reopening blocks
forHcr = false
# we close and reopen the global if (nim_hcr_do_init_) blocks in the main Init function
# for the module so we can have globals and top-level code be interleaved and still
# be able to re-run it but without the top level code - just the init of globals
var hcrInit = default(IfBuilder)
if forHcr:
startBlockWith(targetProc):
hcrInit = initIfStmt(p.s(cpsStmts))
initElifBranch(p.s(cpsStmts), hcrInit, cCall("hcrRegisterGlobal",
getModuleDllPath(p.module, v),
'"' & v.loc.snippet & '"',
cSizeof(rdLoc(v.loc)),
traverseProc,
cCast(ptrType(CPointer), cAddr(v.loc.snippet))))
if value.kind != nkEmpty and valueAsRope.len == 0:
genLineDir(targetProc, vn)
if not isCppCtorCall:
loadInto(targetProc, vn, value, v.loc)
if forHcr:
endBlockWith(targetProc):
finishBranch(p.s(cpsStmts), hcrInit)
finishIfStmt(p.s(cpsStmts), hcrInit)
proc genSingleVar(p: BProc, a: PNode) =
let v = a[0].sym
if sfCompileTime in v.flags:
# fix issue #12640
# {.global, compileTime.} pragma in proc
if sfGlobal in v.flags and p.prc != nil and p.prc.kind == skProc:
discard
else:
return
genSingleVar(p, v, a[0], a[2])
proc genClosureVar(p: BProc, a: PNode) =
var immediateAsgn = a[2].kind != nkEmpty
var v: TLoc = initLocExpr(p, a[0])
genLineDir(p, a)
if immediateAsgn:
loadInto(p, a[0], a[2], v)
elif sfNoInit notin a[0][1].sym.flags:
constructLoc(p, v)
proc genVarStmt(p: BProc, n: PNode) =
for it in n.sons:
if it.kind == nkCommentStmt: continue
if it.kind == nkIdentDefs:
# can be a lifted var nowadays ...
if it[0].kind == nkSym:
genSingleVar(p, it)
else:
genClosureVar(p, it)
else:
genVarTuple(p, it)
proc genIf(p: BProc, n: PNode, d: var TLoc) =
#
# { if (!expr1) goto L1;
# thenPart }
# goto LEnd
# L1:
# { if (!expr2) goto L2;
# thenPart2 }
# goto LEnd
# L2:
# { elsePart }
# Lend:
var
a: TLoc
lelse: TLabel
if not isEmptyType(n.typ) and d.k == locNone:
d = getTemp(p, n.typ)
genLineDir(p, n)
let lend = getLabel(p)
for it in n.sons:
# bug #4230: avoid false sharing between branches:
if d.k == locTemp and isEmptyType(n.typ): d.k = locNone
if it.len == 2:
var scope: ScopeBuilder
startSimpleBlock(p, scope)
a = initLocExprSingleUse(p, it[0])
lelse = getLabel(p)
inc(p.labels)
let ra = rdLoc(a)
p.s(cpsStmts).addSingleIfStmt(cOp(Not, ra)):
p.s(cpsStmts).addGoto(lelse)
if p.module.compileToCpp:
# avoid "jump to label crosses initialization" error:
p.s(cpsStmts).addScope():
expr(p, it[1], d)
else:
expr(p, it[1], d)
endSimpleBlock(p, scope)
if n.len > 1:
p.s(cpsStmts).addGoto(lend)
fixLabel(p, lelse)
elif it.len == 1:
var scope: ScopeBuilder
startSimpleBlock(p, scope)
expr(p, it[0], d)
endSimpleBlock(p, scope)
else: internalError(p.config, n.info, "genIf()")
if n.len > 1: fixLabel(p, lend)
proc genReturnStmt(p: BProc, t: PNode) =
if nfPreventCg in t.flags: return
p.flags.incl beforeRetNeeded
genLineDir(p, t)
if (t[0].kind != nkEmpty): genStmts(p, t[0])
blockLeaveActions(p,
howManyTrys = p.nestedTryStmts.len,
howManyExcepts = p.inExceptBlockLen)
if (p.finallySafePoints.len > 0) and noSafePoints notin p.flags:
# If we're in a finally block, and we came here by exception
# consume it before we return.
var safePoint = p.finallySafePoints[^1]
p.s(cpsStmts).addSingleIfStmt(
cOp(NotEqual,
dotField(safePoint, "status"),
cIntValue(0))):
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "popCurrentException"))
p.s(cpsStmts).addGoto("BeforeRet_")
proc genGotoForCase(p: BProc; caseStmt: PNode) =
for i in 1..<caseStmt.len:
var scope: ScopeBuilder
startSimpleBlock(p, scope)
let it = caseStmt[i]
for j in 0..<it.len-1:
if it[j].kind == nkRange:
localError(p.config, it.info, "range notation not available for computed goto")
return
let val = getOrdValue(it[j])
p.s(cpsStmts).addLabel("NIMSTATE_" & $val)
genStmts(p, it.lastSon)
endSimpleBlock(p, scope)
iterator fieldValuePairs(n: PNode): tuple[memberSym, valueSym: PNode] =
assert(n.kind in {nkLetSection, nkVarSection})
for identDefs in n:
if identDefs.kind == nkIdentDefs:
let valueSym = identDefs[^1]
for i in 0..<identDefs.len-2:
let memberSym = identDefs[i]
yield((memberSym: memberSym, valueSym: valueSym))
proc genComputedGoto(p: BProc; n: PNode) =
# first pass: Generate array of computed labels:
# flatten the loop body because otherwise let and var sections
# wrapped inside stmt lists by inject destructors won't be recognised
let n = n.flattenStmts()
var casePos = -1
var arraySize: int = 0
for i in 0..<n.len:
let it = n[i]
if it.kind == nkCaseStmt:
if lastSon(it).kind != nkOfBranch:
localError(p.config, it.info,
"case statement must be exhaustive for computed goto"); return
casePos = i
if enumHasHoles(it[0].typ):
localError(p.config, it.info,
"case statement cannot work on enums with holes for computed goto"); return
let aSize = lengthOrd(p.config, it[0].typ)
if aSize > 10_000:
localError(p.config, it.info,
"case statement has too many cases for computed goto"); return
arraySize = toInt(aSize)
if firstOrd(p.config, it[0].typ) != 0:
localError(p.config, it.info,
"case statement has to start at 0 for computed goto"); return
if casePos < 0:
localError(p.config, n.info, "no case statement found for computed goto"); return
var id = p.labels+1
inc p.labels, arraySize+1
let tmp = "TMP$1_" % [id.rope]
p.s(cpsStmts).addArrayVarWithInitializer(kind = Global,
name = tmp,
elementType = CPointer,
len = arraySize):
var labelsInit: StructInitializer
p.s(cpsStmts).addStructInitializer(labelsInit, kind = siArray):
for i in 1..arraySize:
p.s(cpsStmts).addField(labelsInit, ""):
p.s(cpsStmts).add(cLabelAddr("TMP" & $(id+i) & "_"))
for j in 0..<casePos:
genStmts(p, n[j])
let caseStmt = n[casePos]
var a: TLoc = initLocExpr(p, caseStmt[0])
let ra = a.rdLoc
# first goto:
p.s(cpsStmts).addComputedGoto(subscript(tmp, ra))
for i in 1..<caseStmt.len:
var scope: ScopeBuilder
startSimpleBlock(p, scope)
let it = caseStmt[i]
for j in 0..<it.len-1:
if it[j].kind == nkRange:
localError(p.config, it.info, "range notation not available for computed goto")
return
let val = getOrdValue(it[j])
let lit = cIntLiteral(toInt64(val)+id+1)
p.s(cpsStmts).addLabel("TMP" & lit & "_")
genStmts(p, it.lastSon)
for j in casePos+1..<n.len:
genStmts(p, n[j])
for j in 0..<casePos:
# prevent new local declarations
# compile declarations as assignments
let it = n[j]
if it.kind in {nkLetSection, nkVarSection}:
let asgn = copyNode(it)
asgn.transitionSonsKind(nkAsgn)
asgn.sons.setLen 2
for sym, value in it.fieldValuePairs:
if value.kind != nkEmpty:
asgn[0] = sym
asgn[1] = value
genStmts(p, asgn)
else:
genStmts(p, it)
var a: TLoc = initLocExpr(p, caseStmt[0])
let ra = a.rdLoc
p.s(cpsStmts).addComputedGoto(subscript(tmp, ra))
endSimpleBlock(p, scope)
for j in casePos+1..<n.len:
genStmts(p, n[j])
proc genWhileStmt(p: BProc, t: PNode) =
# we don't generate labels here as for example GCC would produce
# significantly worse code
var
a: TLoc
assert(t.len == 2)
inc(p.withinLoop)
genLineDir(p, t)
preserveBreakIdx:
var loopBody = t[1]
if loopBody.stmtsContainPragma(wComputedGoto) and
hasComputedGoto in CC[p.config.cCompiler].props:
# for closure support weird loop bodies are generated:
if loopBody.len == 2 and loopBody[0].kind == nkEmpty:
loopBody = loopBody[1]
genComputedGoto(p, loopBody)
else:
var stmt: WhileBuilder
p.breakIdx = startBlockWith(p):
stmt = initWhileStmt(p.s(cpsStmts), cIntValue(1))
p.blocks[p.breakIdx].isLoop = true
a = initLocExpr(p, t[0])
if (t[0].kind != nkIntLit) or (t[0].intVal == 0):
let ra = a.rdLoc
var label: TLabel = ""
assignLabel(p.blocks[p.breakIdx], label)
p.s(cpsStmts).addSingleIfStmt(cOp(Not, ra)):
p.s(cpsStmts).addGoto(label)
genStmts(p, loopBody)
if optProfiler in p.options:
# invoke at loop body exit:
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "nimProfile"))
endBlockWith(p):
finishWhileStmt(p.s(cpsStmts), stmt)
dec(p.withinLoop)
proc genBlock(p: BProc, n: PNode, d: var TLoc) =
if not isEmptyType(n.typ):
# bug #4505: allocate the temp in the outer scope
# so that it can escape the generated {}:
if d.k == locNone:
d = getTemp(p, n.typ)
d.flags.incl(lfEnforceDeref)
preserveBreakIdx:
var scope: ScopeBuilder
p.breakIdx = startSimpleBlock(p, scope)
if n[0].kind != nkEmpty:
# named block?
assert(n[0].kind == nkSym)
var sym = n[0].sym
sym.loc.k = locOther
sym.position = p.breakIdx+1
expr(p, n[1], d)
endSimpleBlock(p, scope)
proc genParForStmt(p: BProc, t: PNode) =
assert(t.len == 3)
inc(p.withinLoop)
genLineDir(p, t)
preserveBreakIdx:
let forLoopVar = t[0].sym
assignLocalVar(p, t[0])
#initLoc(forLoopVar.loc, locLocalVar, forLoopVar.typ, onStack)
#discard mangleName(forLoopVar)
let call = t[1]
assert(call.len == 4 or call.len == 5)
var rangeA = initLocExpr(p, call[1])
var rangeB = initLocExpr(p, call[2])
var stepNode: PNode = nil
# $n at the beginning because of #9710
if call.len == 4: # procName(a, b, annotation)
if call[0].sym.name.s == "||": # `||`(a, b, annotation)
p.s(cpsStmts).addCPragma("omp " & call[3].getStr)
else:
p.s(cpsStmts).addCPragma(call[3].getStr)
else: # `||`(a, b, step, annotation)
stepNode = call[3]
p.s(cpsStmts).addCPragma("omp " & call[4].getStr)
p.breakIdx = startBlockWith(p):
if stepNode == nil:
initForRange(p.s(cpsStmts), forLoopVar.loc.rdLoc, rangeA.rdLoc, rangeB.rdLoc, true)
else:
var step: TLoc = initLocExpr(p, stepNode)
initForStep(p.s(cpsStmts), forLoopVar.loc.rdLoc, rangeA.rdLoc, rangeB.rdLoc, step.rdLoc, true)
p.blocks[p.breakIdx].isLoop = true
genStmts(p, t[2])
endBlockWith(p):
finishFor(p.s(cpsStmts))
dec(p.withinLoop)
proc genBreakStmt(p: BProc, t: PNode) =
var idx = p.breakIdx
if t[0].kind != nkEmpty:
# named break?
assert(t[0].kind == nkSym)
var sym = t[0].sym
doAssert(sym.loc.k == locOther)
idx = sym.position-1
else:
# an unnamed 'break' can only break a loop after 'transf' pass:
while idx >= 0 and not p.blocks[idx].isLoop: dec idx
if idx < 0 or not p.blocks[idx].isLoop:
internalError(p.config, t.info, "no loop to break")
p.blocks[idx].label = "LA" & p.blocks[idx].id.rope
blockLeaveActions(p,
p.nestedTryStmts.len - p.blocks[idx].nestedTryStmts,
p.inExceptBlockLen - p.blocks[idx].nestedExceptStmts)
genLineDir(p, t)
p.s(cpsStmts).addGoto(p.blocks[idx].label)
proc raiseExit(p: BProc) =
assert p.config.exc == excGoto
if nimErrorFlagDisabled notin p.flags:
p.flags.incl nimErrorFlagAccessed
p.s(cpsStmts).addSingleIfStmt(cUnlikely(cDeref("nimErr_"))):
if p.nestedTryStmts.len == 0:
p.flags.incl beforeRetNeeded
# easy case, simply goto 'ret':
p.s(cpsStmts).addGoto("BeforeRet_")
else:
p.s(cpsStmts).addGoto("LA" & $p.nestedTryStmts[^1].label & "_")
proc raiseExitCleanup(p: BProc, destroy: string) =
assert p.config.exc == excGoto
if nimErrorFlagDisabled notin p.flags:
p.flags.incl nimErrorFlagAccessed
p.s(cpsStmts).addSingleIfStmt(cUnlikely(cDeref("nimErr_"))):
p.s(cpsStmts).addStmt():
p.s(cpsStmts).add(destroy)
if p.nestedTryStmts.len == 0:
p.flags.incl beforeRetNeeded
# easy case, simply goto 'ret':
p.s(cpsStmts).addGoto("BeforeRet_")
else:
p.s(cpsStmts).addGoto("LA" & $p.nestedTryStmts[^1].label & "_")
proc finallyActions(p: BProc) =
if p.config.exc != excGoto and p.nestedTryStmts.len > 0 and p.nestedTryStmts[^1].inExcept:
# if the current try stmt have a finally block,
# we must execute it before reraising
let finallyBlock = p.nestedTryStmts[^1].fin
if finallyBlock != nil:
genSimpleBlock(p, finallyBlock[0])
proc raiseInstr(p: BProc; result: var Builder) =
if p.config.exc == excGoto:
let L = p.nestedTryStmts.len
if L == 0:
p.flags.incl beforeRetNeeded
# easy case, simply goto 'ret':
result.addGoto("BeforeRet_")
else:
# raise inside an 'except' must go to the finally block,
# raise outside an 'except' block must go to the 'except' list.
result.addGoto("LA" & $p.nestedTryStmts[L-1].label & "_")
# + ord(p.nestedTryStmts[L-1].inExcept)])
proc genRaiseStmt(p: BProc, t: PNode) =
if t[0].kind != nkEmpty:
var a: TLoc = initLocExprSingleUse(p, t[0])
finallyActions(p)
var e = rdLoc(a)
discard getTypeDesc(p.module, t[0].typ)
var typ = skipTypes(t[0].typ, abstractPtrs)
case p.config.exc
of excCpp:
blockLeaveActions(p, howManyTrys = 0, howManyExcepts = p.inExceptBlockLen)
of excGoto:
blockLeaveActions(p, howManyTrys = 0,
howManyExcepts = (if p.nestedTryStmts.len > 0 and p.nestedTryStmts[^1].inExcept: 1 else: 0))
else:
discard
genLineDir(p, t)
if isImportedException(typ, p.config):
lineF(p, cpsStmts, "throw $1;$n", [e])
else:
let eName = makeCString(typ.sym.name.s)
let pName = makeCString(if p.prc != nil: p.prc.name.s else: p.module.module.name.s)
let fName = quotedFilename(p.config, t.info)
let ln = toLinenumber(t.info)
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "raiseExceptionEx"),
cCast(ptrType(cgsymValue(p.module, "Exception")), e),
eName,
pName,
fName,
cIntValue(ln))
if optOwnedRefs in p.config.globalOptions:
p.s(cpsStmts).addAssignment(e, NimNil)
else:
finallyActions(p)
genLineDir(p, t)
p.s(cpsStmts).addCallStmt(cgsymValue(p.module, "reraiseException"))
raiseInstr(p, p.s(cpsStmts))
template genCaseGenericBranch(p: BProc, b: PNode, e: TLoc, labl: TLabel,
rangeFormat, eqFormat: untyped) =
var x, y: TLoc
for i in 0..<b.len - 1:
let rlabel {.inject.} = labl
if b[i].kind == nkRange:
x = initLocExpr(p, b[i][0])
y = initLocExpr(p, b[i][1])
let ra {.inject.} = rdCharLoc(e)
let rb {.inject.} = rdCharLoc(x)
let rc {.inject.} = rdCharLoc(y)
rangeFormat
else:
x = initLocExpr(p, b[i])
let ra {.inject.} = rdCharLoc(e)
let rb {.inject.} = rdCharLoc(x)
eqFormat
proc genCaseSecondPass(p: BProc, t: PNode, d: var TLoc,
labId, until: int): TLabel =
var lend = getLabel(p)
for i in 1..until:
# bug #4230: avoid false sharing between branches:
if d.k == locTemp and isEmptyType(t.typ): d.k = locNone
p.s(cpsStmts).addLabel("LA" & $(labId + i) & "_")
if t[i].kind == nkOfBranch:
exprBlock(p, t[i][^1], d)
p.s(cpsStmts).addGoto(lend)
else:
exprBlock(p, t[i][0], d)
result = lend
template genIfForCaseUntil(p: BProc, t: PNode, d: var TLoc,
until: int, a: TLoc,
rangeFormat, eqFormat: untyped): TLabel =
# generate a C-if statement for a Nim case statement
var res: TLabel
var labId = p.labels
for i in 1..until:
inc(p.labels)
let lab = "LA" & $p.labels & "_"
if t[i].kind == nkOfBranch: # else statement
genCaseGenericBranch(p, t[i], a, lab, rangeFormat, eqFormat)
else:
p.s(cpsStmts).addGoto(lab)
if until < t.len-1:
inc(p.labels)
var gotoTarget = "LA" & $p.labels & "_"
p.s(cpsStmts).addGoto(gotoTarget)
res = genCaseSecondPass(p, t, d, labId, until)
p.s(cpsStmts).addLabel(gotoTarget)
else:
res = genCaseSecondPass(p, t, d, labId, until)
res
template genCaseGeneric(p: BProc, t: PNode, d: var TLoc,
rangeFormat, eqFormat: untyped) =
var a: TLoc = initLocExpr(p, t[0])
var lend = genIfForCaseUntil(p, t, d, t.len-1, a, rangeFormat, eqFormat)
fixLabel(p, lend)
proc genCaseStringBranch(p: BProc, b: PNode, e: TLoc, labl: TLabel,
stringKind: TTypeKind,
branches: var openArray[Builder]) =
var x: TLoc
for i in 0..<b.len - 1:
assert(b[i].kind != nkRange)
x = initLocExpr(p, b[i])
var j: int = 0
case b[i].kind
of nkStrLit..nkTripleStrLit:
j = int(hashString(p.config, b[i].strVal) and high(branches))
of nkNilLit: j = 0
else:
assert false, "invalid string case branch node kind"
let re = rdLoc(e)
let rx = rdLoc(x)
branches[j].addSingleIfStmtWithCond():
let eqName = if stringKind == tyCstring: "eqCstrings" else: "eqStrings"
branches[j].addCall(cgsymValue(p.module, eqName), re, rx)
do:
branches[j].addGoto(labl)
proc genStringCase(p: BProc, t: PNode, stringKind: TTypeKind, d: var TLoc) =
# count how many constant strings there are in the case:
var strings = 0
for i in 1..<t.len:
if t[i].kind == nkOfBranch: inc(strings, t[i].len - 1)
if strings > stringCaseThreshold:
var bitMask = math.nextPowerOfTwo(strings) - 1
var branches: seq[Builder]
newSeq(branches, bitMask + 1)
var a: TLoc = initLocExpr(p, t[0]) # first pass: generate ifs+goto:
var labId = p.labels
for i in 1..<t.len:
inc(p.labels)
if t[i].kind == nkOfBranch:
genCaseStringBranch(p, t[i], a, "LA" & rope(p.labels) & "_",
stringKind, branches)
else:
# else statement: nothing to do yet
# but we reserved a label, which we use later
discard
let fnName = if stringKind == tyCstring: "hashCstring" else: "hashString"
let ra = rdLoc(a)
p.s(cpsStmts).addSwitchStmt(
cOp(BitAnd, NimInt,
cCall(cgsymValue(p.module, fnName), ra),
cIntValue(bitMask))):
for j in 0..high(branches):
if branches[j].buf.len != 0:
let lit = cIntLiteral(j)
p.s(cpsStmts).addSingleSwitchCase(lit):
p.s(cpsStmts).add(extract(branches[j]))