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new feature: --staticBoundChecks:on to enforce static array index checking (#10965)

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Andreas Rumpf 2020-03-18 14:25:10 +01:00 • committed by GitHub
commit 3f29911a94
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16 changed files with 152 additions and 50 deletions
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47
compiler/guards.nim
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@ -250,7 +250,6 @@ proc pred(n: PNode): PNode =
result = n
proc canon*(n: PNode; o: Operators): PNode =
# XXX for now only the new code in 'semparallel' uses this
if n.safeLen >= 1:
result = shallowCopy(n)
for i in 0..<n.len:
@ -275,7 +274,7 @@ proc canon*(n: PNode; o: Operators): PNode =
result = negate(result[1], result[2], result, o)
of someLen:
result[0] = o.opLen.newSymNode
of someLt:
of someLt - {mLtF64}:
# x < y same as x <= y-1:
let y = n[2].canon(o)
let p = pred(y)
@ -315,12 +314,12 @@ proc canon*(n: PNode; o: Operators): PNode =
if plus != nil and not isLetLocation(x, true):
result = buildCall(result[0].sym, plus, y[1])
else: discard
elif x.isValue and y.getMagic in someAdd and y[2].isValue:
elif x.isValue and y.getMagic in someAdd and y[2].kind == x.kind:
# 0 <= a.len + 3
# -3 <= a.len
result[1] = x |-| y[2]
result[2] = y[1]
elif x.isValue and y.getMagic in someSub and y[2].isValue:
elif x.isValue and y.getMagic in someSub and y[2].kind == x.kind:
# 0 <= a.len - 3
# 3 <= a.len
result[1] = x |+| y[2]
@ -340,6 +339,8 @@ proc usefulFact(n: PNode; o: Operators): PNode =
if isLetLocation(n[1], true) or isLetLocation(n[2], true):
# XXX algebraic simplifications! 'i-1 < a.len' --> 'i < a.len+1'
result = n
elif n[1].getMagic in someLen or n[2].getMagic in someLen:
result = n
of someLe+someLt:
if isLetLocation(n[1], true) or isLetLocation(n[2], true):
# XXX algebraic simplifications! 'i-1 < a.len' --> 'i < a.len+1'
@ -401,10 +402,20 @@ type
TModel* = object
s*: seq[PNode] # the "knowledge base"
o*: Operators
beSmart*: bool
proc addFact*(m: var TModel, nn: PNode) =
let n = usefulFact(nn, m.o)
if n != nil: m.s.add n
if n != nil:
if not m.beSmart:
m.s.add n
else:
let c = canon(n, m.o)
if c.getMagic == mAnd:
addFact(m, c[1])
addFact(m, c[2])
else:
m.s.add c
proc addFactNeg*(m: var TModel, n: PNode) =
let n = n.neg(m.o)
@ -614,6 +625,9 @@ proc impliesGe(fact, x, c: PNode): TImplication =
proc impliesLe(fact, x, c: PNode): TImplication =
if not isLocation(x):
if c.isValue:
if leValue(x, x): return impYes
else: return impNo
return impliesGe(fact, c, x)
case fact[0].sym.magic
of someEq:
@ -799,7 +813,7 @@ proc ple(m: TModel; a, b: PNode): TImplication =
if lastOrd(nil, a.typ) <= b.intVal: return impYes
# 3 <= x iff low(x) <= 3
if a.isValue and b.typ != nil and b.typ.isOrdinalType:
if firstOrd(nil, b.typ) <= a.intVal: return impYes
if a.intVal <= firstOrd(nil, b.typ): return impYes
# x <= x
if sameTree(a, b): return impYes
@ -810,7 +824,11 @@ proc ple(m: TModel; a, b: PNode): TImplication =
# x <= y+c if 0 <= c and x <= y
# x <= y+(-c) if c <= 0 and y >= x
if b.getMagic in someAdd and zero() <=? b[2] and a <=? b[1]: return impYes
if b.getMagic in someAdd:
if zero() <=? b[2] and a <=? b[1]: return impYes
# x <= y-c if x+c <= y
if b[2] <=? zero() and (canon(m.o.opSub.buildCall(a, b[2]), m.o) <=? b[1]):
return impYes
# x+c <= y if c <= 0 and x <= y
if a.getMagic in someAdd and a[2] <=? zero() and a[1] <=? b: return impYes
@ -899,10 +917,13 @@ proc pleViaModelRec(m: var TModel; a, b: PNode): TImplication =
# --> true if (len-100) <= (len-1)
let x = fact[1]
let y = fact[2]
if sameTree(x, a) and y.getMagic in someAdd and b.getMagic in someAdd and
sameTree(y[1], b[1]):
if ple(m, b[2], y[2]) == impYes:
return impYes
# x <= y.
# Question: x <= b? True iff y <= b.
if sameTree(x, a):
if ple(m, y, b) == impYes: return impYes
if y.getMagic in someAdd and b.getMagic in someAdd and sameTree(y[1], b[1]):
if ple(m, b[2], y[2]) == impYes:
return impYes
# x <= y implies a <= b if a <= x and y <= b
if ple(m, a, x) == impYes:
@ -961,6 +982,10 @@ proc proveLe*(m: TModel; a, b: PNode): TImplication =
proc addFactLe*(m: var TModel; a, b: PNode) =
m.s.add canon(m.o.opLe.buildCall(a, b), m.o)
proc addFactLt*(m: var TModel; a, b: PNode) =
let bb = m.o.opAdd.buildCall(b, minusOne())
addFactLe(m, a, bb)
proc settype(n: PNode): PType =
result = newType(tySet, n.typ.owner)
addSonSkipIntLit(result, n.typ)