vmdef

This module contains the type definitions for the new evaluation engine. An instruction is 1-3 int32s in memory, it is a register based VM.

Imports

ast, idents, options, modulegraphs, lineinfos

Types

TInstrType = uint64

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TRegister = range[0 .. 65535'u64.int]

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TDest = range[-1 .. 65535'u64.int]

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TInstr = distinct TInstrType

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TOpcode = enum
  opcEof, opcRet, opcYldYoid, opcYldVal, opcAsgnInt, opcAsgnFloat, opcAsgnRef,
  opcAsgnComplex, opcCastIntToFloat32, opcCastIntToFloat64, opcCastFloatToInt32,
  opcCastFloatToInt64, opcCastPtrToInt, opcCastIntToPtr, opcFastAsgnComplex,
  opcNodeToReg, opcLdArr, opcLdArrAddr, opcWrArr, opcLdObj, opcLdObjAddr,
  opcWrObj, opcAddrReg, opcAddrNode, opcLdDeref, opcWrDeref, opcWrStrIdx,
  opcLdStrIdx, opcAddInt, opcAddImmInt, opcSubInt, opcSubImmInt, opcLenSeq,
  opcLenStr, opcIncl, opcInclRange, opcExcl, opcCard, opcMulInt, opcDivInt,
  opcModInt, opcAddFloat, opcSubFloat, opcMulFloat, opcDivFloat, opcShrInt,
  opcShlInt, opcAshrInt, opcBitandInt, opcBitorInt, opcBitxorInt, opcAddu,
  opcSubu, opcMulu, opcDivu, opcModu, opcEqInt, opcLeInt, opcLtInt, opcEqFloat,
  opcLeFloat, opcLtFloat, opcLeu, opcLtu, opcEqRef, opcEqNimNode,
  opcSameNodeType, opcXor, opcNot, opcUnaryMinusInt, opcUnaryMinusFloat,
  opcBitnotInt, opcEqStr, opcLeStr, opcLtStr, opcEqSet, opcLeSet, opcLtSet,
  opcMulSet, opcPlusSet, opcMinusSet, opcConcatStr, opcContainsSet, opcRepr,
  opcSetLenStr, opcSetLenSeq, opcIsNil, opcOf, opcIs, opcSubStr, opcParseFloat,
  opcConv, opcCast, opcQuit, opcInvalidField, opcNarrowS, opcNarrowU,
  opcSignExtend, opcAddStrCh, opcAddStrStr, opcAddSeqElem, opcRangeChck,
  opcNAdd, opcNAddMultiple, opcNKind, opcNSymKind, opcNIntVal, opcNFloatVal,
  opcNSymbol, opcNIdent, opcNGetType, opcNStrVal, opcNSigHash, opcNGetSize,
  opcNSetIntVal, opcNSetFloatVal, opcNSetSymbol, opcNSetIdent, opcNSetType,
  opcNSetStrVal, opcNNewNimNode, opcNCopyNimNode, opcNCopyNimTree, opcNDel,
  opcGenSym, opcNccValue, opcNccInc, opcNcsAdd, opcNcsIncl, opcNcsLen, opcNcsAt,
  opcNctPut, opcNctLen, opcNctGet, opcNctHasNext, opcNctNext, opcNodeId,
  opcSlurp, opcGorge, opcParseExprToAst, opcParseStmtToAst, opcQueryErrorFlag,
  opcNError, opcNWarning, opcNHint, opcNGetLineInfo, opcNSetLineInfo,
  opcEqIdent, opcStrToIdent, opcGetImpl, opcGetImplTransf, opcEcho, opcIndCall,
  opcIndCallAsgn, opcRaise, opcNChild, opcNSetChild, opcCallSite, opcNewStr,
  opcTJmp, opcFJmp, opcJmp, opcJmpBack, opcBranch, opcTry, opcExcept,
  opcFinally, opcFinallyEnd, opcNew, opcNewSeq, opcLdNull, opcLdNullReg,
  opcLdConst, opcAsgnConst, opcLdGlobal, opcLdGlobalAddr, opcLdGlobalDerefFFI,
  opcLdGlobalAddrDerefFFI, opcLdImmInt, opcNBindSym, opcNDynBindSym, opcSetType,
  opcTypeTrait, opcMarshalLoad, opcMarshalStore, opcSymOwner,
  opcSymIsInstantiationOf

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TBlock = object
  label*: PSym
  fixups*: seq[TPosition]

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TEvalMode = enum
  emRepl,                   ## evaluate because in REPL mode
  emConst,                  ## evaluate for 'const' according to spec
  emOptimize,               ## evaluate for optimization purposes (same as
                             ## emConst?)
  emStaticExpr,             ## evaluate for enforced compile time eval
                             ## ('static' context)
  emStaticStmt               ## 'static' as an expression

reason for evaluation Source Edit

TSandboxFlag = enum
  allowCast,                ## allow unsafe language feature: 'cast'
  allowInfiniteLoops         ## allow endless loops

what the evaluation engine should allow Source Edit

TSandboxFlags = set[TSandboxFlag]

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TSlotKind = enum
  slotEmpty, slotFixedVar, slotFixedLet, slotTempUnknown, slotTempInt,
  slotTempFloat, slotTempStr, slotTempComplex, slotTempPerm

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TRegisterKind = enum
  rkNone, rkNode, rkInt, rkFloat, rkRegisterAddr, rkNodeAddr

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TFullReg = object
  case kind*: TRegisterKind
  of rkNone:
    nil
  of rkInt:
    intVal*: BiggestInt
  of rkFloat:
    floatVal*: BiggestFloat
  of rkNode:
    node*: PNode
  of rkRegisterAddr:
    regAddr*: ptr TFullReg
  of rkNodeAddr:
    nodeAddr*: ptr PNode

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PProc = ref object
  blocks*: seq[TBlock]
  sym*: PSym
  slots*: array[TRegister, tuple[inUse: bool, kind: TSlotKind]]
  maxSlots*: int

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VmArgs = object
  ra*, rb*, rc*: Natural
  slots*: ptr UncheckedArray[TFullReg]
  currentException*: PNode
  currentLineInfo*: TLineInfo

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VmCallback = proc (args: VmArgs) {...}{.closure.}

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PCtx = ref TCtx

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TCtx = object of TPassContext
  code*: seq[TInstr]
  debug*: seq[TLineInfo]
  globals*: PNode
  constants*: PNode
  types*: seq[PType]
  currentExceptionA*, currentExceptionB*: PNode
  exceptionInstr*: int
  prc*: PProc
  module*: PSym
  callsite*: PNode
  mode*: TEvalMode
  features*: TSandboxFlags
  traceActive*: bool
  loopIterations*: int
  comesFromHeuristic*: TLineInfo
  callbacks*: seq[tuple[key: string, value: VmCallback]]
  errorFlag*: string
  cache*: IdentCache
  config*: ConfigRef
  graph*: ModuleGraph
  oldErrorCount*: int
  profiler*: Profiler
  templInstCounter*: ref int

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PStackFrame = ref TStackFrame

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TStackFrame {...}{.acyclic.} = object
  prc*: PSym
  slots*: seq[TFullReg]
  next*: PStackFrame
  comesFrom*: int
  safePoints*: seq[int]

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Profiler = object
  tEnter*: float
  tos*: PStackFrame

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TPosition = distinct int

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PEvalContext = PCtx

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Consts

byteExcess = 128

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regOShift = 0'u

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regAShift = 8'u64

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regBShift = 24'u64

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regCShift = 40'u64

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regBxShift = 24'u64

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regOMask = 255'u64

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regAMask = 65535'u64

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regBMask = 65535'u64

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regCMask = 65535'u64

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regBxMask = 16777215'u64

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wordExcess = 8388608

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regBxMin = -8388607

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regBxMax = 8388607

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firstABxInstr = opcTJmp

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largeInstrs = {opcSubStr, opcConv, opcCast, opcNewSeq, opcOf, opcMarshalLoad,
               opcMarshalStore}

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slotSomeTemp = slotTempUnknown

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relativeJumps = {opcTJmp, opcFJmp, opcJmp, opcJmpBack}

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nimNodeFlag = 16

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Procs

proc newCtx(module: PSym; cache: IdentCache; g: ModuleGraph): PCtx {...}{.raises: [],
    tags: [].}

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proc refresh(c: PCtx; module: PSym) {...}{.raises: [], tags: [].}

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proc registerCallback(c: PCtx; name: string; callback: VmCallback): int {...}{.
    discardable, raises: [], tags: [].}

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Templates

template opcode(x: TInstr): TOpcode

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template regA(x: TInstr): TRegister

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template regB(x: TInstr): TRegister

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template regC(x: TInstr): TRegister

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template regBx(x: TInstr): int

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template jmpDiff(x: TInstr): int

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