1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
#
#
# The Nimrod Compiler
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## This module implements code generation for multi methods.
import
intsets, options, ast, astalgo, msgs, idents, renderer, types, magicsys
proc genConv(n: PNode, d: PType, downcast: bool): PNode =
var dest = skipTypes(d, abstractPtrs)
var source = skipTypes(n.typ, abstractPtrs)
if (source.kind == tyObject) and (dest.kind == tyObject):
var diff = inheritanceDiff(dest, source)
if diff == high(int): InternalError(n.info, "cgmeth.genConv")
if diff < 0:
result = newNodeIT(nkObjUpConv, n.info, d)
addSon(result, n)
if downCast: InternalError(n.info, "cgmeth.genConv: no upcast allowed")
elif diff > 0:
result = newNodeIT(nkObjDownConv, n.info, d)
addSon(result, n)
if not downCast:
InternalError(n.info, "cgmeth.genConv: no downcast allowed")
else:
result = n
else:
result = n
proc methodCall*(n: PNode): PNode =
result = n
# replace ordinary method by dispatcher method:
var disp = lastSon(result.sons[0].sym.ast).sym
assert sfDispatcher in disp.flags
result.sons[0].sym = disp
# change the arguments to up/downcasts to fit the dispatcher's parameters:
for i in countup(1, sonsLen(result)-1):
result.sons[i] = genConv(result.sons[i], disp.typ.sons[i], true)
# save for incremental compilation:
var gMethods: seq[TSymSeq] = @[]
proc sameMethodBucket(a, b: PSym): bool =
result = false
if a.name.id != b.name.id: return
if sonsLen(a.typ) != sonsLen(b.typ):
return # check for return type:
if not sameTypeOrNil(a.typ.sons[0], b.typ.sons[0]): return
for i in countup(1, sonsLen(a.typ) - 1):
var aa = a.typ.sons[i]
var bb = b.typ.sons[i]
while true:
aa = skipTypes(aa, {tyGenericInst})
bb = skipTypes(bb, {tyGenericInst})
if (aa.kind == bb.kind) and (aa.kind in {tyVar, tyPtr, tyRef}):
aa = aa.sons[0]
bb = bb.sons[0]
else:
break
if sameType(aa, bb) or
(aa.kind == tyObject) and (bb.kind == tyObject) and
(inheritanceDiff(bb, aa) < 0):
nil
else:
return
result = true
proc attachDispatcher(s: PSym, dispatcher: PNode) =
var L = s.ast.len-1
var x = s.ast.sons[L]
if x.kind == nkSym and sfDispatcher in x.sym.flags:
# we've added a dispatcher already, so overwrite it
s.ast.sons[L] = dispatcher
else:
s.ast.add(dispatcher)
proc methodDef*(s: PSym, fromCache: bool) =
var L = len(gMethods)
for i in countup(0, L - 1):
if sameMethodBucket(gMethods[i][0], s):
add(gMethods[i], s)
attachDispatcher(s, lastSon(gMethods[i][0].ast))
return
add(gMethods, @[s])
# create a new dispatcher:
if not fromCache:
var disp = copySym(s)
incl(disp.flags, sfDispatcher)
excl(disp.flags, sfExported)
disp.typ = copyType(disp.typ, disp.typ.owner, false)
# we can't inline the dispatcher itself (for now):
if disp.typ.callConv == ccInline: disp.typ.callConv = ccDefault
disp.ast = copyTree(s.ast)
disp.ast.sons[bodyPos] = ast.emptyNode
if s.typ.sons[0] != nil:
disp.ast.sons[resultPos].sym = copySym(s.ast.sons[resultPos].sym)
attachDispatcher(s, newSymNode(disp))
# attach to itself to prevent bugs:
attachDispatcher(disp, newSymNode(disp))
proc relevantCol(methods: TSymSeq, col: int): bool =
# returns true iff the position is relevant
var t = methods[0].typ.sons[col]
result = false
if skipTypes(t, skipPtrs).kind == tyObject:
for i in countup(1, high(methods)):
if not SameType(methods[i].typ.sons[col], t):
return true
proc cmpSignatures(a, b: PSym, relevantCols: TIntSet): int =
result = 0
for col in countup(1, sonsLen(a.typ) - 1):
if Contains(relevantCols, col):
var aa = skipTypes(a.typ.sons[col], skipPtrs)
var bb = skipTypes(b.typ.sons[col], skipPtrs)
var d = inheritanceDiff(aa, bb)
if (d != high(int)):
return d
proc sortBucket(a: var TSymSeq, relevantCols: TIntSet) =
# we use shellsort here; fast and simple
var N = len(a)
var h = 1
while true:
h = 3 * h + 1
if h > N: break
while true:
h = h div 3
for i in countup(h, N - 1):
var v = a[i]
var j = i
while cmpSignatures(a[j - h], v, relevantCols) >= 0:
a[j] = a[j - h]
j = j - h
if j < h: break
a[j] = v
if h == 1: break
proc genDispatcher(methods: TSymSeq, relevantCols: TIntSet): PSym =
var base = lastSon(methods[0].ast).sym
result = base
var paramLen = sonsLen(base.typ)
var disp = newNodeI(nkIfStmt, base.info)
var ands = getSysSym("and")
var iss = getSysSym("of")
for meth in countup(0, high(methods)):
var curr = methods[meth] # generate condition:
var cond: PNode = nil
for col in countup(1, paramLen - 1):
if Contains(relevantCols, col):
var isn = newNodeIT(nkCall, base.info, getSysType(tyBool))
addSon(isn, newSymNode(iss))
addSon(isn, newSymNode(base.typ.n.sons[col].sym))
addSon(isn, newNodeIT(nkType, base.info, curr.typ.sons[col]))
if cond != nil:
var a = newNodeIT(nkCall, base.info, getSysType(tyBool))
addSon(a, newSymNode(ands))
addSon(a, cond)
addSon(a, isn)
cond = a
else:
cond = isn
var call = newNodeI(nkCall, base.info)
addSon(call, newSymNode(curr))
for col in countup(1, paramLen - 1):
addSon(call, genConv(newSymNode(base.typ.n.sons[col].sym),
curr.typ.sons[col], false))
var ret: PNode
if base.typ.sons[0] != nil:
var a = newNodeI(nkAsgn, base.info)
addSon(a, newSymNode(base.ast.sons[resultPos].sym))
addSon(a, call)
ret = newNodeI(nkReturnStmt, base.info)
addSon(ret, a)
else:
ret = call
if cond != nil:
var a = newNodeI(nkElifBranch, base.info)
addSon(a, cond)
addSon(a, ret)
addSon(disp, a)
else:
disp = ret
result.ast.sons[bodyPos] = disp
proc generateMethodDispatchers*(): PNode =
result = newNode(nkStmtList)
for bucket in countup(0, len(gMethods) - 1):
var relevantCols = initIntSet()
for col in countup(1, sonsLen(gMethods[bucket][0].typ) - 1):
if relevantCol(gMethods[bucket], col): Incl(relevantCols, col)
sortBucket(gMethods[bucket], relevantCols)
addSon(result, newSymNode(genDispatcher(gMethods[bucket], relevantCols)))
|