#
#
# The Nimrod Compiler
# (c) Copyright 2012 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
# This include implements the high level optimization pass.
proc hlo(c: PContext, n: PNode): PNode
proc evalPattern(c: PContext, n, orig: PNode): PNode =
InternalAssert n.kind == nkCall and n.sons[0].kind == nkSym
# we need to ensure that the resulting AST is semchecked. However, it's
# aweful to semcheck before macro invocation, so we don't and treat
# templates and macros as immediate in this context.
var rule: string
if optHints in gOptions and hintPattern in gNotes:
rule = renderTree(n, {renderNoComments})
let s = n.sons[0].sym
case s.kind
of skMacro:
result = semMacroExpr(c, n, orig, s)
of skTemplate:
result = semTemplateExpr(c, n, s)
else:
result = semDirectOp(c, n, {})
if optHints in gOptions and hintPattern in gNotes:
Message(orig.info, hintPattern, rule & " --> '" &
renderTree(result, {renderNoComments}) & "'")
# check the resulting AST for optimization rules again:
result = hlo(c, result)
proc applyPatterns(c: PContext, n: PNode): PNode =
result = n
# we apply the last pattern first, so that pattern overriding is possible;
# however the resulting AST would better not trigger the old rule then
# anymore ;-)
for i in countdown(<c.patterns.len, 0):
let pattern = c.patterns[i]
if not isNil(pattern):
let x = applyRule(c, pattern, result)
if not isNil(x):
assert x.kind in {nkStmtList, nkCall}
inc(evalTemplateCounter)
if evalTemplateCounter > 100:
GlobalError(n.info, errTemplateInstantiationTooNested)
# deactivate this pattern:
c.patterns[i] = nil
if x.kind == nkStmtList:
assert x.len == 3
x.sons[1] = evalPattern(c, x.sons[1], result)
result = flattenStmts(x)
else:
result = evalPattern(c, x, result)
dec(evalTemplateCounter)
# activate this pattern again:
c.patterns[i] = pattern
proc hlo(c: PContext, n: PNode): PNode =
case n.kind
of nkMacroDef, nkTemplateDef, procDefs:
# already processed (special cases in semstmts.nim)
result = n
else:
result = applyPatterns(c, n)
if result == n:
# no optimization applied, try subtrees:
for i in 0 .. < safeLen(result):
let a = result.sons[i]
let h = hlo(c, a)
if h != a: result.sons[i] = h
else:
# perform type checking, so that the replacement still fits:
if n.typ == nil and (result.typ == nil or
result.typ.kind in {tyStmt, tyEmpty}):
nil
else:
result = fitNode(c, n.typ, result)
proc hloBody(c: PContext, n: PNode): PNode =
# fast exit:
if c.patterns.len == 0 or optPatterns notin gOptions: return n
result = hlo(c, n)
proc hloStmt(c: PContext, n: PNode): PNode =
# fast exit:
if c.patterns.len == 0 or optPatterns notin gOptions: return n
result = hlo(c, n)