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Diffstat (limited to 'compiler/trees.nim')
-rw-r--r-- | compiler/trees.nim | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/compiler/trees.nim b/compiler/trees.nim new file mode 100644 index 000000000..41b54eb09 --- /dev/null +++ b/compiler/trees.nim @@ -0,0 +1,238 @@ +# +# +# 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 = + result = false + 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 + else: + result = false + else: + result = false + +proc sameTree*(a, b: PNode): bool = + result = false + 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 = + result = false + 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.baseClass != nil: + result = false + elif isCaseObj(t.n): + result = false + else: + result = true + else: + result = true + else: result = false + +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 + else: + result = false + else: + result = false + +proc whichPragma*(n: PNode): TSpecialWord = + let key = if n.kind in nkPragmaCallKinds and n.len > 0: n[0] else: n + case key.kind + of nkIdent: result = whichKeyword(key.ident) + of nkSym: result = whichKeyword(key.sym.name) + of nkCast: return wCast + of nkClosedSymChoice, nkOpenSymChoice: + return whichPragma(key[0]) + else: return wInvalid + if result in nonPragmaWordsLow..nonPragmaWordsHigh: + result = wInvalid + +proc isNoSideEffectPragma*(n: PNode): bool = + var k = whichPragma(n) + if k == wCast: + k = whichPragma(n[1]) + result = k == wNoSideEffect + +proc findPragma*(n: PNode, which: TSpecialWord): PNode = + result = nil + if n.kind == nkPragma: + for son in n: + if whichPragma(son) == which: + return son + +proc effectSpec*(n: PNode, effectType: TSpecialWord): PNode = + result = nil + 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 = + result = nil + 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 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 + else: + result = nil + 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: result = nil + else: result = nil + +proc stupidStmtListExpr*(n: PNode): bool = + for i in 0..<n.len-1: + if n[i].kind notin {nkEmpty, nkCommentStmt}: return false + result = true + +proc dontInlineConstant*(orig, cnst: PNode): bool {.inline.} = + # symbols that expand to a complex constant (array, etc.) should not be + # inlined, unless it's the empty array: + result = cnst.kind in {nkCurly, nkPar, nkTupleConstr, nkBracket, nkObjConstr} and + cnst.len > ord(cnst.kind == nkObjConstr) + +proc isRunnableExamples*(n: PNode): bool = + # Templates and generics don't perform symbol lookups. + result = n.kind == nkSym and n.sym.magic == mRunnableExamples or + n.kind == nkIdent and n.ident.id == ord(wRunnableExamples) + +proc skipAddr*(n: PNode): PNode {.inline.} = + result = if n.kind in {nkAddr, nkHiddenAddr}: n[0] else: n |