summary refs log tree commit diff stats
path: root/compiler/trees.nim
blob: c5c1a0d75f0b5fd746b5229552a121b5608fcc20 (plain) (blame)
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
#
#
#           The Nim Compiler
#        (c) Copyright 2012 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

# tree helper routines

import
  ast, wordrecg, idents

proc cyclicTreeAux(n: PNode, visited: var seq[PNode]): bool =
  if n == nil: return
  for v in visited:
    if v == n: return true
  if not (n.kind in {nkEmpty..nkNilLit}):
    visited.add(n)
    for nSon in n.sons:
      if cyclicTreeAux(nSon, visited): return true
    discard visited.pop()

proc cyclicTree*(n: PNode): bool =
  var visited: seq[PNode] = @[]
  cyclicTreeAux(n, visited)

proc sameFloatIgnoreNan(a, b: BiggestFloat): bool {.inline.} =
  ## ignores NaN semantics, but ensures 0.0 == -0.0, see #13730
  cast[uint64](a) == cast[uint64](b) or a == b

proc exprStructuralEquivalent*(a, b: PNode; strictSymEquality=false): bool =
  if a == b:
    result = true
  elif (a != nil) and (b != nil) and (a.kind == b.kind):
    case a.kind
    of nkSym:
      if strictSymEquality:
        result = a.sym == b.sym
      else:
        # don't go nuts here: same symbol as string is enough:
        result = a.sym.name.id == b.sym.name.id
    of nkIdent: result = a.ident.id == b.ident.id
    of nkCharLit..nkUInt64Lit: result = a.intVal == b.intVal
    of nkFloatLit..nkFloat64Lit: result = sameFloatIgnoreNan(a.floatVal, b.floatVal)
    of nkStrLit..nkTripleStrLit: result = a.strVal == b.strVal
    of nkCommentStmt: result = a.comment == b.comment
    of nkEmpty, nkNilLit, nkType: result = true
    else:
      if a.len == b.len:
        for i in 0..<a.len:
          if not exprStructuralEquivalent(a[i], b[i],
                                          strictSymEquality): return
        result = true

proc sameTree*(a, b: PNode): bool =
  if a == b:
    result = true
  elif a != nil and b != nil and a.kind == b.kind:
    if a.flags != b.flags: return
    if a.info.line != b.info.line: return
    if a.info.col != b.info.col:
      return                  #if a.info.fileIndex <> b.info.fileIndex then exit;
    case a.kind
    of nkSym:
      # don't go nuts here: same symbol as string is enough:
      result = a.sym.name.id == b.sym.name.id
    of nkIdent: result = a.ident.id == b.ident.id
    of nkCharLit..nkUInt64Lit: result = a.intVal == b.intVal
    of nkFloatLit..nkFloat64Lit: result = sameFloatIgnoreNan(a.floatVal, b.floatVal)
    of nkStrLit..nkTripleStrLit: result = a.strVal == b.strVal
    of nkEmpty, nkNilLit, nkType: result = true
    else:
      if a.len == b.len:
        for i in 0..<a.len:
          if not sameTree(a[i], b[i]): return
        result = true

proc getMagic*(op: PNode): TMagic =
  if op == nil: return mNone
  case op.kind
  of nkCallKinds:
    case op[0].kind
    of nkSym: result = op[0].sym.magic
    else: result = mNone
  else: result = mNone

proc isConstExpr*(n: PNode): bool =
  const atomKinds = {nkCharLit..nkNilLit} # Char, Int, UInt, Str, Float and Nil literals
  n.kind in atomKinds or nfAllConst in n.flags

proc isCaseObj*(n: PNode): bool =
  if n.kind == nkRecCase: return true
  for i in 0..<n.safeLen:
    if n[i].isCaseObj: return true

proc isDeepConstExpr*(n: PNode; preventInheritance = false): bool =
  case n.kind
  of nkCharLit..nkNilLit:
    result = true
  of nkExprEqExpr, nkExprColonExpr, nkHiddenStdConv, nkHiddenSubConv:
    result = isDeepConstExpr(n[1], preventInheritance)
  of nkCurly, nkBracket, nkPar, nkTupleConstr, nkObjConstr, nkClosure, nkRange:
    for i in ord(n.kind == nkObjConstr)..<n.len:
      if not isDeepConstExpr(n[i], preventInheritance): return false
    if n.typ.isNil: result = true
    else:
      let t = n.typ.skipTypes({tyGenericInst, tyDistinct, tyAlias, tySink, tyOwned})
      if t.kind in {tyRef, tyPtr} or tfUnion in t.flags: return false
      if t.kind == tyObject:
        if preventInheritance and t[0] != nil:
          result = false
        elif isCaseObj(t.n):
          result = false
        else:
          result = true
      else:
        result = true
  else: discard

proc isRange*(n: PNode): bool {.inline.} =
  if n.kind in nkCallKinds:
    let callee = n[0]
    if (callee.kind == nkIdent and callee.ident.id == ord(wDotDot)) or
       (callee.kind == nkSym and callee.sym.name.id == ord(wDotDot)) or
       (callee.kind in {nkClosedSymChoice, nkOpenSymChoice} and
        callee[1].sym.name.id == ord(wDotDot)):
      result = true

proc whichPragma*(n: PNode): TSpecialWord =
  let key = if n.kind in nkPragmaCallKinds and n.len > 0: n[0] else: n
  if key.kind == nkIdent: result = whichKeyword(key.ident)

proc findPragma*(n: PNode, which: TSpecialWord): PNode =
  if n.kind == nkPragma:
    for son in n:
      if whichPragma(son) == which:
        return son

proc effectSpec*(n: PNode, effectType: TSpecialWord): PNode =
  for i in 0..<n.len:
    var it = n[i]
    if it.kind == nkExprColonExpr and whichPragma(it) == effectType:
      result = it[1]
      if result.kind notin {nkCurly, nkBracket}:
        result = newNodeI(nkCurly, result.info)
        result.add(it[1])
      return

proc propSpec*(n: PNode, effectType: TSpecialWord): PNode =
  for i in 0..<n.len:
    var it = n[i]
    if it.kind == nkExprColonExpr and whichPragma(it) == effectType:
      return it[1]

proc unnestStmts(n, result: PNode) =
  if n.kind == nkStmtList:
    for x in items(n): unnestStmts(x, result)
  elif n.kind notin {nkCommentStmt, nkNilLit}:
    result.add(n)

proc flattenStmts*(n: PNode): PNode =
  result = newNodeI(nkStmtList, n.info)
  unnestStmts(n, result)
  if result.len == 1:
    result = result[0]

proc extractRange*(k: TNodeKind, n: PNode, a, b: int): PNode =
  result = newNodeI(k, n.info, b-a+1)
  for i in 0..b-a: result[i] = n[i+a]

proc isTrue*(n: PNode): bool =
  n.kind == nkSym and n.sym.kind == skEnumField and n.sym.position != 0 or
    n.kind == nkIntLit and n.intVal != 0

proc getRoot*(n: PNode): PSym =
  ## ``getRoot`` takes a *path* ``n``. A path is an lvalue expression
  ## like ``obj.x[i].y``. The *root* of a path is the symbol that can be
  ## determined as the owner; ``obj`` in the example.
  case n.kind
  of nkSym:
    if n.sym.kind in {skVar, skResult, skTemp, skLet, skForVar, skParam}:
      result = n.sym
  of nkDotExpr, nkBracketExpr, nkHiddenDeref, nkDerefExpr,
      nkObjUpConv, nkObjDownConv, nkCheckedFieldExpr, nkHiddenAddr, nkAddr:
    result = getRoot(n[0])
  of nkHiddenStdConv, nkHiddenSubConv, nkConv:
    result = getRoot(n[1])
  of nkCallKinds:
    if getMagic(n) == mSlice: result = getRoot(n[1])
  else: discard