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-rw-r--r--compiler/vmgen.nim174
1 files changed, 104 insertions, 70 deletions
diff --git a/compiler/vmgen.nim b/compiler/vmgen.nim
index 206cca0d7..b594c00a9 100644
--- a/compiler/vmgen.nim
+++ b/compiler/vmgen.nim
@@ -139,25 +139,12 @@ proc getTemp(c: PCtx; typ: PType): TRegister =
       if not c.slots[i].inUse:
         c.slots[i] = (inUse: true, kind: k)
         return TRegister(i)
+  if c.maxSlots >= high(TRegister):
+    internalError("cannot generate code; too many registers required")
   result = TRegister(c.maxSlots)
   c.slots[c.maxSlots] = (inUse: true, kind: k)
   inc c.maxSlots
 
-proc getGlobalSlot(c: PCtx; n: PNode; s: PSym): TRegister =
-  let p = c.prc
-  for i in 0 .. p.maxSlots-1:
-    if p.globals[i] == s.id: return TRegister(i)
-
-  result = TRegister(p.maxSlots)
-  p.slots[p.maxSlots] = (inUse: true, kind: slotFixedVar)
-  p.globals[p.maxSlots] = s.id
-  inc p.maxSlots
-  # XXX this is still not correct! We need to load the global in a proc init
-  # section, otherwise control flow could lead to a usage before it's been
-  # loaded.
-  c.gABx(n, opcGlobalAlias, result, s.position)
-  # XXX add some internal asserts here
-
 proc freeTemp(c: PCtx; r: TRegister) =
   let c = c.prc
   if c.slots[r].kind >= slotSomeTemp: c.slots[r].inUse = false
@@ -322,13 +309,7 @@ proc genAndOr(c: PCtx; n: PNode; opc: TOpcode; dest: var TDest) =
   c.patch(L1)
 
 proc nilLiteral(n: PNode): PNode =
-  if n.kind == nkNilLit and n.typ.sym != nil and
-       n.typ.sym.magic == mPNimrodNode:
-    let nilo = newNodeIT(nkNilLit, n.info, n.typ)
-    result = newNodeIT(nkMetaNode, n.info, n.typ)
-    result.add nilo
-  else:
-    result = n
+  result = n
 
 proc rawGenLiteral(c: PCtx; n: PNode): int =
   result = c.constants.len
@@ -470,21 +451,37 @@ proc genCall(c: PCtx; n: PNode; dest: var TDest) =
     c.gABC(n, opcIndCallAsgn, dest, x, n.len)
   c.freeTempRange(x, n.len)
 
+template isGlobal(s: PSym): bool = sfGlobal in s.flags and s.kind != skForVar
+
 proc needsAsgnPatch(n: PNode): bool = 
-  n.kind in {nkBracketExpr, nkDotExpr, nkCheckedFieldExpr}
+  n.kind in {nkBracketExpr, nkDotExpr, nkCheckedFieldExpr,
+             nkDerefExpr, nkHiddenDeref} or (n.kind == nkSym and n.sym.isGlobal)
 
 proc genAsgnPatch(c: PCtx; le: PNode, value: TRegister) =
   case le.kind
   of nkBracketExpr:
-    let dest = c.genx(le.sons[0])
+    let dest = c.genx(le.sons[0], {gfAddrOf})
     let idx = c.genx(le.sons[1])
-    c.gABC(le, opcWrArrRef, dest, idx, value)
+    c.gABC(le, opcWrArr, dest, idx, value)
+    c.freeTemp(dest)
+    c.freeTemp(idx)
   of nkDotExpr, nkCheckedFieldExpr:
     # XXX field checks here
     let left = if le.kind == nkDotExpr: le else: le.sons[0]
-    let dest = c.genx(left.sons[0])
+    let dest = c.genx(left.sons[0], {gfAddrOf})
     let idx = c.genx(left.sons[1])
-    c.gABC(left, opcWrObjRef, dest, idx, value)
+    c.gABC(left, opcWrObj, dest, idx, value)
+    c.freeTemp(dest)
+    c.freeTemp(idx)
+  of nkDerefExpr, nkHiddenDeref:
+    let dest = c.genx(le.sons[0], {gfAddrOf})
+    c.gABC(le, opcWrDeref, dest, value)
+    c.freeTemp(dest)
+  of nkSym:
+    if le.sym.isGlobal:
+      let dest = c.genx(le, {gfAddrOf})
+      c.gABC(le, opcWrDeref, dest, value)
+      c.freeTemp(dest)
   else:
     discard
 
@@ -594,10 +591,10 @@ proc genAddSubInt(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode) =
 
 proc genConv(c: PCtx; n, arg: PNode; dest: var TDest; opc=opcConv) =  
   let tmp = c.genx(arg)
-  c.gABx(n, opcSetType, tmp, genType(c, arg.typ))
   if dest < 0: dest = c.getTemp(n.typ)
   c.gABC(n, opc, dest, tmp)
   c.gABx(n, opc, 0, genType(c, n.typ))
+  c.gABx(n, opc, 0, genType(c, arg.typ))
   c.freeTemp(tmp)
 
 proc genCard(c: PCtx; n: PNode; dest: var TDest) =
@@ -623,6 +620,7 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest) =
     c.genAddSubInt(n, dest, opcAddInt)
   of mInc, mDec:
     unused(n, dest)
+    # XXX generates inefficient code for globals
     var d = c.genx(n.sons[1]).TDest
     c.genAddSubInt(n, d, if m == mInc: opcAddInt else: opcSubInt)
     c.genAsgnPatch(n.sons[1], d)
@@ -636,6 +634,7 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest) =
     c.genNewSeq(n)
   of mNewString:
     genUnaryABC(c, n, dest, opcNewStr)
+    # XXX buggy
   of mNewStringOfCap:
     # we ignore the 'cap' argument and translate it as 'newString(0)'.
     # eval n.sons[1] for possible side effects:
@@ -644,6 +643,7 @@ proc genMagic(c: PCtx; n: PNode; dest: var TDest) =
     if dest < 0: dest = c.getTemp(n.typ)
     c.gABC(n, opcNewStr, dest, tmp)
     c.freeTemp(tmp)
+    # XXX buggy
   of mLengthOpenArray, mLengthArray, mLengthSeq:
     genUnaryABI(c, n, dest, opcLenSeq)
   of mLengthStr:
@@ -905,6 +905,10 @@ const
     tyFloat, tyFloat32, tyFloat64, tyFloat128,
     tyUInt, tyUInt8, tyUInt16, tyUInt32, tyUInt64}
 
+proc fitsRegister*(t: PType): bool =
+  t.skipTypes(abstractInst-{tyTypeDesc}).kind in {
+    tyRange, tyEnum, tyBool, tyInt..tyUInt64}
+
 proc requiresCopy(n: PNode): bool =
   if n.typ.skipTypes(abstractInst-{tyTypeDesc}).kind in atomicTypes:
     result = false
@@ -919,7 +923,8 @@ proc unneededIndirection(n: PNode): bool =
 proc genAddrDeref(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
                   flags: TGenFlags) = 
   # a nop for certain types
-  let flags = if opc == opcAddr: flags+{gfAddrOf} else: flags
+  let isAddr = opc in {opcAddrNode, opcAddrReg}
+  let flags = if isAddr: flags+{gfAddrOf} else: flags
   # consider:
   # proc foo(f: var ref int) =
   #   f = new(int)
@@ -929,12 +934,17 @@ proc genAddrDeref(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
   #
   # The type of 'f' is 'var ref int' and of 'x' is 'ref int'. Hence for
   # nkAddr we must not use 'unneededIndirection', but for deref we use it.
-  if opc != opcAddr and unneededIndirection(n.sons[0]):
+  if not isAddr and unneededIndirection(n.sons[0]):
     gen(c, n.sons[0], dest, flags)
   else:
     let tmp = c.genx(n.sons[0], flags)
     if dest < 0: dest = c.getTemp(n.typ)
-    gABC(c, n, opc, dest, tmp)
+    if not isAddr:
+      gABC(c, n, opc, dest, tmp)
+    elif c.prc.slots[tmp].kind >= slotTempUnknown:
+      gABC(c, n, opcAddrReg, dest, tmp)
+    else:
+      gABC(c, n, opcAddrNode, dest, tmp)
     c.freeTemp(tmp)
 
 proc whichAsgnOpc(n: PNode): TOpcode =
@@ -952,8 +962,7 @@ proc whichAsgnOpc(n: PNode): TOpcode =
 
 proc isRef(t: PType): bool = t.skipTypes(abstractRange-{tyTypeDesc}).kind == tyRef
 
-proc whichAsgnOpc(n: PNode; opc: TOpcode): TOpcode =
-  if isRef(n.typ): succ(opc) else: opc
+proc whichAsgnOpc(n: PNode; opc: TOpcode): TOpcode = opc
 
 proc genAsgn(c: PCtx; dest: TDest; ri: PNode; requiresCopy: bool) =
   let tmp = c.genx(ri)
@@ -961,8 +970,6 @@ proc genAsgn(c: PCtx; dest: TDest; ri: PNode; requiresCopy: bool) =
   gABC(c, ri, whichAsgnOpc(ri), dest, tmp)
   c.freeTemp(tmp)
 
-template isGlobal(s: PSym): bool = sfGlobal in s.flags and s.kind != skForVar
-
 proc setSlot(c: PCtx; v: PSym) =
   # XXX generate type initialization here?
   if v.position == 0:
@@ -974,29 +981,36 @@ proc setSlot(c: PCtx; v: PSym) =
 proc genAsgn(c: PCtx; le, ri: PNode; requiresCopy: bool) =
   case le.kind
   of nkBracketExpr:
-    let dest = c.genx(le.sons[0])
+    let dest = c.genx(le.sons[0], {gfAddrOf})
     let idx = c.genx(le.sons[1])
     let tmp = c.genx(ri)
     if le.sons[0].typ.skipTypes(abstractVarRange-{tyTypeDesc}).kind in {
         tyString, tyCString}:
       c.gABC(le, opcWrStrIdx, dest, idx, tmp)
     else:
-      c.gABC(le, whichAsgnOpc(le, opcWrArr), dest, idx, tmp)
+      c.gABC(le, opcWrArr, dest, idx, tmp)
     c.freeTemp(tmp)
   of nkDotExpr, nkCheckedFieldExpr:
     # XXX field checks here
     let left = if le.kind == nkDotExpr: le else: le.sons[0]
-    let dest = c.genx(left.sons[0])
+    let dest = c.genx(left.sons[0], {gfAddrOf})
     let idx = c.genx(left.sons[1])
     let tmp = c.genx(ri)
-    c.gABC(left, whichAsgnOpc(left, opcWrObj), dest, idx, tmp)
+    c.gABC(left, opcWrObj, dest, idx, tmp)
+    c.freeTemp(tmp)
+  of nkDerefExpr, nkHiddenDeref:
+    let dest = c.genx(le, {gfAddrOf})
+    let tmp = c.genx(ri)
+    c.gABC(le, opcWrDeref, dest, tmp)
     c.freeTemp(tmp)
   of nkSym:
     let s = le.sym
     if s.isGlobal:
       withTemp(tmp, le.typ):
-        gen(c, ri, tmp)
-        c.gABx(le, whichAsgnOpc(le, opcWrGlobal), tmp, s.position)
+        c.gen(le, tmp, {gfAddrOf})
+        let val = c.genx(ri)
+        c.gABC(le, opcWrDeref, tmp, val)
+        c.freeTemp(val)
     else:
       if s.kind == skForVar and c.mode == emRepl: c.setSlot s
       internalAssert s.position > 0 or (s.position == 0 and
@@ -1004,7 +1018,7 @@ proc genAsgn(c: PCtx; le, ri: PNode; requiresCopy: bool) =
       var dest: TRegister = s.position + ord(s.kind == skParam)
       gen(c, ri, dest)
   else:
-    let dest = c.genx(le)
+    let dest = c.genx(le, {gfAddrOf})
     genAsgn(c, dest, ri, requiresCopy)
 
 proc genLit(c: PCtx; n: PNode; dest: var TDest) =
@@ -1034,18 +1048,22 @@ proc cannotEval(n: PNode) {.noinline.} =
   globalError(n.info, errGenerated, "cannot evaluate at compile time: " &
     n.renderTree)
 
+proc getNullValue*(typ: PType, info: TLineInfo): PNode
+
 proc genGlobalInit(c: PCtx; n: PNode; s: PSym) =
-  c.globals.add(emptyNode.copyNode)
+  c.globals.add(getNullValue(s.typ, n.info))
   s.position = c.globals.len
   # This is rather hard to support, due to the laziness of the VM code
   # generator. See tests/compile/tmacro2 for why this is necesary:
   #   var decls{.compileTime.}: seq[PNimrodNode] = @[]
-  c.gABx(n, opcGlobalOnce, 0, s.position)
+  let dest = c.getTemp(s.typ)
+  c.gABx(n, opcLdGlobal, dest, s.position)
   let tmp = c.genx(s.ast)
-  c.gABx(n, whichAsgnOpc(n, opcWrGlobal), tmp, s.position)
+  c.gABC(n, opcWrDeref, dest, tmp)
+  c.freeTemp(dest)
   c.freeTemp(tmp)
 
-proc genRdVar(c: PCtx; n: PNode; dest: var TDest) =
+proc genRdVar(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags) =
   let s = n.sym
   if s.isGlobal:
     if sfCompileTime in s.flags or c.mode == emRepl:
@@ -1055,9 +1073,12 @@ proc genRdVar(c: PCtx; n: PNode; dest: var TDest) =
     if s.position == 0:
       if sfImportc in s.flags: c.importcSym(n.info, s)
       else: genGlobalInit(c, n, s)
-    if dest < 0:
-      dest = c.getGlobalSlot(n, s)
-      #c.gABx(n, opcAliasGlobal, dest, s.position)
+    if dest < 0: dest = c.getTemp(n.typ)
+    if gfAddrOf notin flags and fitsRegister(s.typ):
+      var cc = c.getTemp(n.typ)
+      c.gABx(n, opcLdGlobal, cc, s.position)
+      c.gABC(n, opcNodeToReg, dest, cc)
+      c.freeTemp(cc)
     else:
       c.gABx(n, opcLdGlobal, dest, s.position)
   else:
@@ -1078,7 +1099,13 @@ proc genAccess(c: PCtx; n: PNode; dest: var TDest; opc: TOpcode;
   let a = c.genx(n.sons[0], flags)
   let b = c.genx(n.sons[1], {})
   if dest < 0: dest = c.getTemp(n.typ)
-  c.gABC(n, (if gfAddrOf in flags: succ(opc) else: opc), dest, a, b)
+  if gfAddrOf notin flags and fitsRegister(n.typ):
+    var cc = c.getTemp(n.typ)
+    c.gABC(n, opc, cc, a, b)
+    c.gABC(n, opcNodeToReg, dest, cc)
+    c.freeTemp(cc)
+  else:
+    c.gABC(n, opc, dest, a, b)
   c.freeTemp(a)
   c.freeTemp(b)
 
@@ -1096,7 +1123,6 @@ proc genArrAccess(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags) =
   else:
     genAccess(c, n, dest, opcLdArr, flags)
 
-proc getNullValue*(typ: PType, info: TLineInfo): PNode
 proc getNullValueAux(obj: PNode, result: PNode) = 
   case obj.kind
   of nkRecList:
@@ -1121,12 +1147,7 @@ proc getNullValue(typ: PType, info: TLineInfo): PNode =
     result = newNodeIT(nkFloatLit, info, t)
   of tyVar, tyPointer, tyPtr, tyCString, tySequence, tyString, tyExpr,
      tyStmt, tyTypeDesc, tyStatic, tyRef:
-    if t.sym != nil and t.sym.magic == mPNimrodNode:
-      let nilo = newNodeIT(nkNilLit, info, t)
-      result = newNodeIT(nkMetaNode, info, t)
-      result.add nilo
-    else:
-      result = newNodeIT(nkNilLit, info, t)
+    result = newNodeIT(nkNilLit, info, t)
   of tyProc:
     if t.callConv != ccClosure:
       result = newNodeIT(nkNilLit, info, t)
@@ -1154,6 +1175,9 @@ proc getNullValue(typ: PType, info: TLineInfo): PNode =
     result = newNodeIT(nkCurly, info, t)
   else: internalError("getNullValue: " & $t.kind)
 
+proc ldNullOpcode(t: PType): TOpcode =
+  if fitsRegister(t): opcLdNullReg else: opcLdNull
+
 proc genVarSection(c: PCtx; n: PNode) =
   for a in n:
     if a.kind == nkCommentStmt: continue
@@ -1164,8 +1188,8 @@ proc genVarSection(c: PCtx; n: PNode) =
         setSlot(c, a[i].sym)
         # v = t[i]
         var v: TDest = -1
-        genRdVar(c, a[i], v)
-        c.gABC(n, opcLdObj, v, tmp, i)
+        genRdVar(c, a[i], v, {gfAddrOf})
+        c.gABC(n, opcWrObj, v, tmp, i)
         # XXX globals?
       c.freeTemp(tmp)
     elif a.sons[0].kind == nkSym:
@@ -1177,27 +1201,28 @@ proc genVarSection(c: PCtx; n: PNode) =
             let sa = if s.ast.isNil: getNullValue(s.typ, a.info) else: s.ast
             c.globals.add(sa)
             s.position = c.globals.len
-            # "Once support" is unnecessary here
         if a.sons[2].kind == nkEmpty:
           when false:
             withTemp(tmp, s.typ):
               c.gABx(a, opcLdNull, tmp, c.genType(s.typ))
               c.gABx(a, whichAsgnOpc(a.sons[0], opcWrGlobal), tmp, s.position)
         else:
-          let tmp = genx(c, a.sons[2])
-          c.gABx(a, whichAsgnOpc(a.sons[0], opcWrGlobal), tmp, s.position)
+          let tmp = c.genx(a.sons[0], {gfAddrOf})
+          let val = c.genx(a.sons[2])
+          c.gABC(a, opcWrDeref, tmp, val)
+          c.freeTemp(val)
           c.freeTemp(tmp)
       else:
         setSlot(c, s)
         if a.sons[2].kind == nkEmpty:
-          c.gABx(a, opcLdNull, s.position, c.genType(s.typ))
+          c.gABx(a, ldNullOpcode(s.typ), s.position, c.genType(s.typ))
         else:
           gen(c, a.sons[2], s.position.TRegister)
     else:
       # assign to a.sons[0]; happens for closures
       if a.sons[2].kind == nkEmpty:
         let tmp = genx(c, a.sons[0])
-        c.gABx(a, opcLdNull, tmp, c.genType(a.sons[0].typ))
+        c.gABx(a, ldNullOpcode(a[0].typ), tmp, c.genType(a.sons[0].typ))
         c.freeTemp(tmp)
       else:
         genAsgn(c, a.sons[0], a.sons[2], true)
@@ -1205,10 +1230,19 @@ proc genVarSection(c: PCtx; n: PNode) =
 proc genArrayConstr(c: PCtx, n: PNode, dest: var TDest) =
   if dest < 0: dest = c.getTemp(n.typ)
   c.gABx(n, opcLdNull, dest, c.genType(n.typ))
+
+  let intType = getSysType(tyInt)
+  let seqType = n.typ.skipTypes(abstractVar-{tyTypeDesc})
+  if seqType.kind == tySequence:
+    var tmp = c.getTemp(intType)
+    c.gABx(n, opcLdImmInt, tmp, n.len)
+    c.gABx(n, opcNewSeq, dest, c.genType(seqType))
+    c.gABx(n, opcNewSeq, tmp, 0)
+    c.freeTemp(tmp)
+  
   if n.len > 0:
-    let intType = getSysType(tyInt)
     var tmp = getTemp(c, intType)
-    c.gABx(n, opcLdNull, tmp, c.genType(intType))
+    c.gABx(n, opcLdNullReg, tmp, c.genType(intType))
     for x in n:
       let a = c.genx(x)
       c.gABC(n, whichAsgnOpc(x, opcWrArr), dest, tmp, a)
@@ -1274,7 +1308,7 @@ proc gen(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags = {}) =
     let s = n.sym
     case s.kind
     of skVar, skForVar, skTemp, skLet, skParam, skResult:
-      genRdVar(c, n, dest)
+      genRdVar(c, n, dest, flags)
     of skProc, skConverter, skMacro, skTemplate, skMethod, skIterator:
       # 'skTemplate' is only allowed for 'getAst' support:
       if sfImportc in s.flags: c.importcSym(n.info, s)
@@ -1320,8 +1354,8 @@ proc gen(c: PCtx; n: PNode; dest: var TDest; flags: TGenFlags = {}) =
   of nkDotExpr: genObjAccess(c, n, dest, flags)
   of nkCheckedFieldExpr: genCheckedObjAccess(c, n, dest, flags)
   of nkBracketExpr: genArrAccess(c, n, dest, flags)
-  of nkDerefExpr, nkHiddenDeref: genAddrDeref(c, n, dest, opcDeref, flags)
-  of nkAddr, nkHiddenAddr: genAddrDeref(c, n, dest, opcAddr, flags)
+  of nkDerefExpr, nkHiddenDeref: genAddrDeref(c, n, dest, opcLdDeref, flags)
+  of nkAddr, nkHiddenAddr: genAddrDeref(c, n, dest, opcAddrNode, flags)
   of nkWhenStmt, nkIfStmt, nkIfExpr: genIf(c, n, dest)
   of nkCaseStmt: genCase(c, n, dest)
   of nkWhileStmt:
@@ -1506,7 +1540,7 @@ proc genProc(c: PCtx; s: PSym): int =
     c.gABC(body, opcEof, eofInstr.regA)
     c.optimizeJumps(result)
     s.offset = c.prc.maxSlots
-    #if s.name.s == "concatStyleInterpolation":
+    #if s.name.s == "importImpl_forward" or s.name.s == "importImpl":
     #  c.echoCode(result)
     # echo renderTree(body)
     c.prc = oldPrc