Closed
Description
The following code segfaults with newruntime enabled. Two workarounds are specified in the source code, which seem to trigger different a compiler output.
EDIT: sorry, I left out some code necessary for reproduction. It's now there.
EDIT 2: to make matters even more complex, compiling the code with -d:danger, fixes the crash as well.
Example
type
MemState* = enum
memPrivate
MemPermisison* = enum
memperm_Read
MemInfo* = ref object
base*, size*: uint32
state*: MemState
perm*: set[MemPermisison]
MemBlock = ref object
info: MemInfo
data: seq[byte]
UserProcessMemory* = ref object
pageAccess: array[0x40000, ptr UncheckedArray[byte]]
pages: array[0x40000, MemInfo]
blocks: seq[owned MemBlock]
proc allocMemory*(mem: UserProcessMemory, base, size: uint32) =
let
roundedBase = base and not(0xFFF'u32)
roundedSize = (size + 0xFFF) and not(0xFFF'u32)
echo "allocating ", base, " ", size
for i in (roundedBase shr 12)..<((roundedBase + roundedSize) shr 12):
#echo "span ", i
doAssert mem.pages[i] == nil
# TODO: beserer fehler
let memBlock = MemBlock(
info: MemInfo(
base: roundedBase,
size: roundedSize,
state: memPrivate,
perm: {memperm_Read}
),
data: newSeq[byte](roundedSize))
for i in 0..<(roundedSize shr 12):
mem.pages[i + (roundedBase shr 12)] = memBlock.info
#echo cast[uint64](addr mem.pageAccess[i + (roundedBase shr 12)])
mem.pageAccess[i + (roundedBase shr 12)] = cast[ptr UncheckedArray[byte]](addr memBlock.data[i * 0x1000])
mem.blocks.add memBlock
#for i in (roundedBase shr 12)..<((roundedBase + roundedSize) shr 12):
# assert mem.pageAccess[i] != nil
proc fillPages*(mem: UserProcessMemory, start: uint32, data: seq[byte]) =
echo "filling page from ", start, " len ", data.len
assert (start and not(0xFFF'u32)) == start
assert (uint32(data.len) and not(0xFFF'u32)) == uint32(data.len)
for i in (start shr 12)..<((start + uint32(data.len)) shr 12):
#echo cast[uint64](addr mem.pageAccess[i])
let page = mem.pageAccess[i]
assert page != nil
#copyMem(page, unsafeAddr data[i * 0x1000 - start], 0x1000)
const base = 0x00100000
proc a(): owned UserProcessMemory =
result = UserProcessMemory()
result.allocMemory(base, 0x1000 * 16)
result.fillPages(base, newSeq[byte](0x1000 * 16))
discard a()Current Output
allocating 1048576 65536
filling page from 1048576 len 65536
c:\Users\Kemal\Desktop\workframe\importer.nim(67) importer
c:\Users\Kemal\Desktop\workframe\importer.nim(65) a
c:\Users\Kemal\Desktop\workframe\importer.nim(57) fillPages
C:\Nim\lib\system\assertions.nim(27) failedAssertImpl
C:\Nim\lib\system\assertions.nim(20) raiseAssert
C:\Nim\lib\system\fatal.nim(39) sysFatal
Error: unhandled exception: c:\Users\Kemal\Desktop\workframe\importer.nim(57, 16) `page != nil` [AssertionError]Expected Output
allocating 1048576 65536
filling page from 1048576 len 65536
Nim Compiler Version 1.1.1 [Windows: amd64]
Compiled at 2019-11-15
Copyright (c) 2006-2019 by Andreas Rumpf
git hash: 83b7656c0e723a2e68459733e7706f3611a1ddc8
active boot switches: -d:release