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#
#
# The Nim Compiler
# (c) Copyright 2016 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## Computes hash values for routine (proc, method etc) signatures.
import ast, md5
from hashes import Hash
from astalgo import debug
from types import typeToString
from strutils import startsWith
when false:
type
SigHash* = uint32 ## a hash good enough for a filename or a proc signature
proc sdbmHash(hash: SigHash, c: char): SigHash {.inline.} =
return SigHash(c) + (hash shl 6) + (hash shl 16) - hash
template `&=`*(x: var SigHash, c: char) = x = sdbmHash(x, c)
template `&=`*(x: var SigHash, s: string) =
for c in s: x = sdbmHash(x, c)
else:
type
SigHash* = distinct Md5Digest
const
cb64 = [
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N",
"O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z",
"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n",
"o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",
"0", "1", "2", "3", "4", "5", "6", "7", "8", "9a",
"9b", "9c"]
proc toBase64a(s: cstring, len: int): string =
## encodes `s` into base64 representation.
result = newStringOfCap(((len + 2) div 3) * 4)
result.add '_'
var i = 0
while i < len - 2:
let a = ord(s[i])
let b = ord(s[i+1])
let c = ord(s[i+2])
result.add cb64[a shr 2]
result.add cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
result.add cb64[((b and 0x0F) shl 2) or ((c and 0xC0) shr 6)]
result.add cb64[c and 0x3F]
inc(i, 3)
if i < len-1:
let a = ord(s[i])
let b = ord(s[i+1])
result.add cb64[a shr 2]
result.add cb64[((a and 3) shl 4) or ((b and 0xF0) shr 4)]
result.add cb64[((b and 0x0F) shl 2)]
elif i < len:
let a = ord(s[i])
result.add cb64[a shr 2]
result.add cb64[(a and 3) shl 4]
proc `$`*(u: SigHash): string =
toBase64a(cast[cstring](unsafeAddr u), sizeof(u))
proc `&=`(c: var MD5Context, s: string) = md5Update(c, s, s.len)
proc `&=`(c: var MD5Context, ch: char) = md5Update(c, unsafeAddr ch, 1)
template lowlevel(v) =
md5Update(c, cast[cstring](unsafeAddr(v)), sizeof(v))
proc `==`*(a, b: SigHash): bool =
# {.borrow.}
result = equalMem(unsafeAddr a, unsafeAddr b, sizeof(a))
proc hash*(u: SigHash): Hash =
result = 0
for x in 0..3:
result = (result shl 8) or u.MD5Digest[x].int
proc hashSym(c: var MD5Context, s: PSym) =
if sfAnon in s.flags or s.kind == skGenericParam:
c &= ":anon"
else:
var it = s
while it != nil:
c &= it.name.s
c &= "."
it = it.owner
proc hashTree(c: var MD5Context, n: PNode) =
if n == nil:
c &= "\255"
return
let k = n.kind
c &= char(k)
# we really must not hash line information. 'n.typ' is debatable but
# shouldn't be necessary for now and avoids potential infinite recursions.
case n.kind
of nkEmpty, nkNilLit, nkType: discard
of nkIdent:
c &= n.ident.s
of nkSym:
hashSym(c, n.sym)
of nkCharLit..nkUInt64Lit:
let v = n.intVal
lowlevel v
of nkFloatLit..nkFloat64Lit:
let v = n.floatVal
lowlevel v
of nkStrLit..nkTripleStrLit:
c &= n.strVal
else:
for i in 0.. <n.len: hashTree(c, n.sons[i])
type
ConsiderFlag* = enum
CoProc
CoType
proc hashType(c: var MD5Context, t: PType; flags: set[ConsiderFlag]) =
if t == nil:
c &= "\254"
return
c &= char(t.kind)
case t.kind
of tyGenericInst:
var x = t.lastSon
if x.kind == tyGenericBody: x = x.lastSon
if x.kind == tyTuple:
c.hashType x, flags
return
for i in countup(0, sonsLen(t) - 2):
c.hashType t.sons[i], flags
return
of tyGenericInvocation:
for i in countup(0, sonsLen(t) - 1):
c.hashType t.sons[i], flags
return
of tyDistinct:
if CoType in flags:
c.hashType t.lastSon, flags
else:
c.hashSym(t.sym)
return
else:
discard
case t.kind
of tyObject, tyEnum:
# Every cyclic type in Nim need to be constructed via some 't.sym', so this
# is actually safe without an infinite recursion check:
if t.sym != nil:
c.hashSym(t.sym)
else:
lowlevel(t.id)
of tyRef, tyPtr, tyGenericBody, tyAlias:
c.hashType t.lastSon, flags
of tyUserTypeClass:
if t.sym != nil and t.sym.owner != nil:
c &= t.sym.owner.name.s
else:
c &= "unknown typeclass"
of tyUserTypeClassInst:
let body = t.sons[0]
c.hashSym body.sym
for i in countup(1, sonsLen(t) - 2):
c.hashType t.sons[i], flags
of tyFromExpr, tyFieldAccessor:
c.hashTree(t.n)
of tyTuple:
if t.n != nil and CoType notin flags:
assert(sonsLen(t.n) == sonsLen(t))
for i in countup(0, sonsLen(t.n) - 1):
assert(t.n.sons[i].kind == nkSym)
c &= t.n.sons[i].sym.name.s
c &= ':'
c.hashType(t.sons[i], flags)
c &= ','
else:
for i in countup(0, sonsLen(t) - 1): c.hashType t.sons[i], flags
of tyRange:
#if CoType notin flags:
c.hashTree(t.n)
c.hashType(t.sons[0], flags)
of tyProc:
c &= (if tfIterator in t.flags: "iterator " else: "proc ")
if CoProc in flags and t.n != nil:
let params = t.n
for i in 1..<params.len:
let param = params[i].sym
c &= param.name.s
c &= ':'
c.hashType(param.typ, flags)
c &= ','
c.hashType(t.sons[0], flags)
else:
for i in 0.. <t.len: c.hashType(t.sons[i], flags)
c &= char(t.callConv)
if CoType notin flags:
if tfNoSideEffect in t.flags: c &= ".noSideEffect"
if tfThread in t.flags: c &= ".thread"
else:
for i in 0.. <t.len: c.hashType(t.sons[i], flags)
if tfNotNil in t.flags and CoType notin flags: c &= "not nil"
when defined(debugSigHashes):
import db_sqlite
let db = open(connection="sighashes.db", user="araq", password="",
database="sighashes")
proc hashType*(t: PType; flags: set[ConsiderFlag] = {CoType}): SigHash =
var c: MD5Context
md5Init c
hashType c, t, flags
md5Final c, result.Md5Digest
when defined(debugSigHashes):
db.exec(sql"INSERT OR IGNORE INTO sighashes(type, hash) VALUES (?, ?)",
typeToString(t), $result)
proc hashProc*(s: PSym): SigHash =
var c: MD5Context
md5Init c
hashType c, s.typ, {CoProc}
var m = s
while m.kind != skModule: m = m.owner
let p = m.owner
assert p.kind == skPackage
c &= p.name.s
c &= "."
c &= m.name.s
md5Final c, result.Md5Digest
proc hashOwner*(s: PSym): SigHash =
var c: MD5Context
md5Init c
var m = s
while m.kind != skModule: m = m.owner
let p = m.owner
assert p.kind == skPackage
c &= p.name.s
c &= "."
c &= m.name.s
md5Final c, result.Md5Digest
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