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forward type alignment information to seqs (#12430)

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Arne Döring 2020-04-19 07:52:01 +02:00 • committed by GitHub
commit 4005f0d0e4
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25 changed files with 152 additions and 114 deletions
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16
lib/system/seqs_v2.nim
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@ -31,27 +31,27 @@ const nimSeqVersion {.core.} = 2
# XXX make code memory safe for overflows in '*'
proc newSeqPayload(cap, elemSize: int): pointer {.compilerRtl, raises: [].} =
proc newSeqPayload(cap, elemSize, elemAlign: int): pointer {.compilerRtl, raises: [].} =
# we have to use type erasure here as Nim does not support generic
# compilerProcs. Oh well, this will all be inlined anyway.
if cap > 0:
var p = cast[ptr NimSeqPayloadBase](allocShared0(cap * elemSize + sizeof(NimSeqPayloadBase)))
var p = cast[ptr NimSeqPayloadBase](allocShared0(align(sizeof(NimSeqPayloadBase), elemAlign) + cap * elemSize))
p.cap = cap
result = p
else:
result = nil
proc prepareSeqAdd(len: int; p: pointer; addlen, elemSize: int): pointer {.
proc prepareSeqAdd(len: int; p: pointer; addlen, elemSize, elemAlign: int): pointer {.
noSideEffect, raises: [].} =
{.noSideEffect.}:
template `+!`(p: pointer, s: int): pointer =
cast[pointer](cast[int](p) +% s)
const headerSize = sizeof(NimSeqPayloadBase)
let headerSize = align(sizeof(NimSeqPayloadBase), elemAlign)
if addlen <= 0:
result = p
elif p == nil:
result = newSeqPayload(len+addlen, elemSize)
result = newSeqPayload(len+addlen, elemSize, elemAlign)
else:
# Note: this means we cannot support things that have internal pointers as
# they get reallocated here. This needs to be documented clearly.
@ -87,7 +87,7 @@ proc grow*[T](x: var seq[T]; newLen: Natural; value: T) =
if newLen <= oldLen: return
var xu = cast[ptr NimSeqV2[T]](addr x)
if xu.p == nil or xu.p.cap < newLen:
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newLen - oldLen, sizeof(T)))
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newLen - oldLen, sizeof(T), alignof(T)))
xu.len = newLen
for i in oldLen .. newLen-1:
xu.p.data[i] = value
@ -102,7 +102,7 @@ proc add*[T](x: var seq[T]; value: sink T) {.magic: "AppendSeqElem", noSideEffec
let oldLen = x.len
var xu = cast[ptr NimSeqV2[T]](addr x)
if xu.p == nil or xu.p.cap < oldLen+1:
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, 1, sizeof(T)))
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, 1, sizeof(T), alignof(T)))
xu.len = oldLen+1
# .nodestroy means `xu.p.data[oldLen] = value` is compiled into a
# copyMem(). This is fine as know by construction that
@ -119,5 +119,5 @@ proc setLen[T](s: var seq[T], newlen: Natural) =
if newlen <= oldLen: return
var xu = cast[ptr NimSeqV2[T]](addr s)
if xu.p == nil or xu.p.cap < newlen:
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newlen - oldLen, sizeof(T)))
xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newlen - oldLen, sizeof(T), alignof(T)))
xu.len = newlen