alias analysis as required for the code gen and the HLO

compiler/aliases.nim

@@ -0,0 +1,182 @@
+#
+#
+#           The Nimrod Compiler
+#        (c) Copyright 2011 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Simple alias analysis for the HLO and the code generators.
+
+import
+  ast, astalgo, types, trees, intsets, msgs
+  
+type
+  TAnalysisResult* = enum
+    arNo, arMaybe, arYes
+
+proc isPartOfAux(a, b: PType, marker: var TIntSet): TAnalysisResult
+
+proc isPartOfAux(n: PNode, b: PType, marker: var TIntSet): TAnalysisResult =
+  result = arNo
+  case n.kind
+  of nkRecList: 
+    for i in countup(0, sonsLen(n) - 1): 
+      result = isPartOfAux(n.sons[i], b, marker)
+      if result == arYes: return
+  of nkRecCase:
+    assert(n.sons[0].kind == nkSym)
+    result = isPartOfAux(n.sons[0], b, marker)
+    if result == arYes: return
+    for i in countup(1, sonsLen(n) - 1): 
+      case n.sons[i].kind
+      of nkOfBranch, nkElse: 
+        result = isPartOfAux(lastSon(n.sons[i]), b, marker)
+        if result == arYes: return
+      else: internalError("isPartOfAux(record case branch)")
+  of nkSym:
+    result = isPartOfAux(n.sym.typ, b, marker)
+  else: internalError(n.info, "isPartOfAux()")
+  
+proc isPartOfAux(a, b: PType, marker: var TIntSet): TAnalysisResult = 
+  result = arNo
+  if a == nil: return 
+  if ContainsOrIncl(marker, a.id): return 
+  if compareTypes(a, b, dcEqIgnoreDistinct): return arYes
+  case a.kind
+  of tyObject: 
+    result = isPartOfAux(a.sons[0], b, marker)
+    if result == arNo: result = isPartOfAux(a.n, b, marker)
+  of tyGenericInst, tyDistinct:
+    result = isPartOfAux(lastSon(a), b, marker)
+  of tyArray, tyArrayConstr, tySet, tyTuple: 
+    for i in countup(0, sonsLen(a) - 1): 
+      result = isPartOfAux(a.sons[i], b, marker)
+      if result == arYes: return 
+  else: nil
+
+proc isPartOf(a, b: PType): TAnalysisResult = 
+  ## checks iff 'a' can be part of 'b'. Iterates over VALUE types!
+  var marker = InitIntSet()
+  # watch out: parameters reversed because I'm too lazy to change the code...
+  result = isPartOfAux(b, a, marker)
+
+proc isPartOf*(a, b: PNode): TAnalysisResult =
+  ## checks if location `a` can be part of location `b`. We treat seqs and
+  ## strings as pointers because the code gen often just passes them as such.
+  ##
+  ## Note: `a` can only be part of `b`, if `a`'s type can be part of `b`'s
+  ## type. Since however type analysis is more expensive, we perform it only
+  ## if necessary.
+  ##
+  ## cases: 
+  ##
+  ## YES-cases:
+  ##  x    <| x   # for general trees
+  ##  x[]  <| x
+  ##  x[i] <| x
+  ##  x.f  <| x
+  ##  
+  ## NO-cases:
+  ## x           !<| y    # depending on type and symbol kind
+  ## x[constA]   !<| x[constB]
+  ## x.f         !<| x.g
+  ## x.f         !<| y.f  iff x !<= y
+  ##
+  ## MAYBE-cases:
+  ##
+  ##  x[] ?<| y[]   iff compatible type
+  ##
+  ## 
+  ##  x[]  ?<| y  depending on type
+  ##  
+  if a.kind == b.kind:
+    case a.kind
+    of nkSym:
+      const varKinds = {skVar, skTemp, skProc}
+      # same symbol: aliasing:
+      if a.sym.id == b.sym.id: result = arYes
+      elif a.sym.kind in varKinds or b.sym.kind in varKinds: 
+        # actually, a param could alias a var but we know that cannot happen
+        # here. XXX make this more generic
+        result = arNo
+      else:
+        # use expensive type check:
+        if isPartOf(a.sym.typ, b.sym.typ) != arNo:
+          result = arMaybe
+    of nkBracketExpr:
+      result = isPartOf(a[0], b[0])
+      if len(a) >= 2 and len(b) >= 2:
+        # array accesses:
+        if result == arYes and isDeepConstExpr(a[1]) and isDeepConstExpr(b[1]):
+          # we know it's the same array and we have 2 constant indexes; 
+          # if they are 
+          var x = if a[1].kind == nkHiddenStdConv: a[1][1] else: a[1]
+          var y = if b[1].kind == nkHiddenStdConv: b[1][1] else: b[1]
+          
+          if SameValue(x, y): result = arYes
+          else: result = arNo
+        # else: maybe and no are accurate
+      else:
+        # pointer derefs:
+        if result != arYes:
+          if isPartOf(a.typ, b.typ) != arNo: result = arMaybe
+      
+    of nkDotExpr:
+      result = isPartOf(a[0], b[0])
+      if result != arNo:
+        # if the fields are different, it's not the same location
+        if a[1].sym.id != b[1].sym.id:
+          result = arNo
+
+    of nkHiddenDeref, nkDerefExpr:
+      result = isPartOf(a[0], b[0])
+      # weaken because of indirection:
+      if result != arYes:
+        if isPartOf(a.typ, b.typ) != arNo: result = arMaybe
+      
+    of nkHiddenStdConv, nkHiddenSubConv, nkConv:
+      result = isPartOf(a[1], b[1])
+    of nkObjUpConv, nkObjDownConv, nkCheckedFieldExpr:
+      result = isPartOf(a[0], b[0])
+    else: nil
+    # Calls return a new location, so a default of ``arNo`` is fine.
+  else:
+    # go down recursively; this is quite demanding:
+    const 
+      Ix0Kinds = {nkDotExpr, nkBracketExpr, nkObjUpConv, nkObjDownConv,
+                  nkCheckedFieldExpr}
+      Ix1Kinds = {nkHiddenStdConv, nkHiddenSubConv, nkConv}
+      DerefKinds = {nkHiddenDeref, nkDerefExpr}
+    case b.kind
+    of Ix0Kinds:
+      # a* !<| b.f  iff  a* !<| b
+      result = isPartOf(a, b[0])
+    
+    of DerefKinds:
+      # a* !<| b[] iff 
+      if isPartOf(a.typ, b.typ) != arNo:
+        result = isPartOf(a, b[0])
+        if result == arNo: result = arMaybe
+    
+    of Ix1Kinds:
+      # a* !<| T(b)  iff a* !<| b
+      result = isPartOf(a, b[1])
+    
+    of nkSym:
+      # b is an atom, so we have to check a:
+      case a.kind
+      of Ix0Kinds:
+        # a.f !<| b*  iff  a.f !<| b*
+        result = isPartOf(a[0], b)
+      of Ix1Kinds:
+        result = isPartOf(a[1], b)
+      
+      of DerefKinds:
+        if isPartOf(a.typ, b.typ) != arNo:
+          result = isPartOf(a[0], b)
+          if result == arNo: result = arMaybe
+      else: nil
+    else: nil
+

compiler/ast.nim

@@ -371,7 +371,7 @@ type
     mFields, mFieldPairs,
     mAppendStrCh, mAppendStrStr, mAppendSeqElem, 
     mInRange, mInSet, mRepr, mExit, mSetLengthStr, mSetLengthSeq, 
-    mAssert, mAstToStr, mRand,
+    mIsPartOf, mAstToStr, mRand, 
     mSwap, mIsNil, mArrToSeq, mCopyStr, mCopyStrLast, 
     mNewString, mNewStringOfCap,
     mReset,
@@ -669,36 +669,7 @@ const                         # for all kind of hash tables:
   GrowthFactor* = 2           # must be power of 2, > 0
   StartSize* = 8              # must be power of 2, > 0
 
-proc SameValue*(a, b: PNode): bool
+proc ValueToString*(a: PNode): string = 
-  # a, b are literals
-proc leValue*(a, b: PNode): bool
-  # a <= b? a, b are literals
-proc ValueToString*(a: PNode): string
- 
-proc leValue(a, b: PNode): bool = 
-  # a <= b?
-  result = false
-  case a.kind
-  of nkCharLit..nkInt64Lit: 
-    if b.kind in {nkCharLit..nkInt64Lit}: result = a.intVal <= b.intVal
-  of nkFloatLit..nkFloat64Lit: 
-    if b.kind in {nkFloatLit..nkFloat64Lit}: result = a.floatVal <= b.floatVal
-  of nkStrLit..nkTripleStrLit: 
-    if b.kind in {nkStrLit..nkTripleStrLit}: result = a.strVal <= b.strVal
-  else: InternalError(a.info, "leValue")
-  
-proc SameValue(a, b: PNode): bool = 
-  result = false
-  case a.kind
-  of nkCharLit..nkInt64Lit: 
-    if b.kind in {nkCharLit..nkInt64Lit}: result = a.intVal == b.intVal
-  of nkFloatLit..nkFloat64Lit: 
-    if b.kind in {nkFloatLit..nkFloat64Lit}: result = a.floatVal == b.floatVal
-  of nkStrLit..nkTripleStrLit: 
-    if b.kind in {nkStrLit..nkTripleStrLit}: result = a.strVal == b.strVal
-  else: InternalError(a.info, "SameValue")
-  
-proc ValueToString(a: PNode): string = 
   case a.kind
   of nkCharLit..nkInt64Lit: result = $(a.intVal)
   of nkFloatLit, nkFloat32Lit, nkFloat64Lit: result = $(a.floatVal)

compiler/astalgo.nim

@@ -146,6 +146,32 @@ proc IITablePut*(t: var TIITable, key, val: int)
 
 # implementation
 
+proc SameValue*(a, b: PNode): bool = 
+  result = false
+  case a.kind
+  of nkCharLit..nkInt64Lit: 
+    if b.kind in {nkCharLit..nkInt64Lit}: result = a.intVal == b.intVal
+  of nkFloatLit..nkFloat64Lit: 
+    if b.kind in {nkFloatLit..nkFloat64Lit}: result = a.floatVal == b.floatVal
+  of nkStrLit..nkTripleStrLit: 
+    if b.kind in {nkStrLit..nkTripleStrLit}: result = a.strVal == b.strVal
+  else: 
+    debug a
+    debug b
+    InternalError(a.info, "SameValue")
+
+proc leValue*(a, b: PNode): bool = 
+  # a <= b?
+  result = false
+  case a.kind
+  of nkCharLit..nkInt64Lit: 
+    if b.kind in {nkCharLit..nkInt64Lit}: result = a.intVal <= b.intVal
+  of nkFloatLit..nkFloat64Lit: 
+    if b.kind in {nkFloatLit..nkFloat64Lit}: result = a.floatVal <= b.floatVal
+  of nkStrLit..nkTripleStrLit: 
+    if b.kind in {nkStrLit..nkTripleStrLit}: result = a.strVal <= b.strVal
+  else: InternalError(a.info, "leValue")
+
 proc lookupInRecord(n: PNode, field: PIdent): PSym = 
   result = nil
   case n.kind

compiler/ccgexprs.nim

@@ -1378,13 +1378,6 @@ proc genMagicExpr(p: BProc, e: PNode, d: var TLoc, op: TMagic) =
   of mCStrToStr: genDollar(p, e, d, "#cstrToNimstr($1)")
   of mStrToStr: expr(p, e.sons[1], d)
   of mEnumToStr: genRepr(p, e, d)
-  of mAssert:
-    if optAssert in p.Options:
-      expr(p, e.sons[1], d)
-      line = toRope(toLinenumber(e.info))
-      filen = makeCString(ToFilename(e.info))
-      appcg(p, cpsStmts, "#internalAssert($1, $2, $3);$n",
-           [filen, line, rdLoc(d)])
   of mOf: genOf(p, e, d)
   of mNew: genNew(p, e)
   of mNewFinalize: genNewFinalize(p, e)

compiler/ecmasgen.nim

@@ -1132,14 +1132,6 @@ proc genMagic(p: var TProc, n: PNode, r: var TCompRes) =
   of mLtStr: binaryExpr(p, n, r, "cmpStrings", "(cmpStrings($1, $2) < 0)")
   of mIsNil: unaryExpr(p, n, r, "", "$1 == null")
   of mEnumToStr: genRepr(p, n, r)
-  of mAssert:
-    if (optAssert in p.Options):
-      useMagic(p, "internalAssert")
-      gen(p, n.sons[1], a)
-      line = toRope(toLinenumber(n.info))
-      filen = makeCString(ToFilename(n.info))
-      appf(r.com, "if (!($3)) internalAssert($1, $2)",
-           [filen, line, mergeExpr(a)])
   of mNew, mNewFinalize: genNew(p, n, r)
   of mSizeOf: r.res = toRope(getSize(n.sons[1].typ))
   of mChr, mArrToSeq: gen(p, n.sons[1], r)      # nothing to do

compiler/evals.nim

@@ -696,12 +696,6 @@ proc evalNewSeq(c: PEvalContext, n: PNode): PNode =
     a.sons[i] = getNullValue(t.sons[0], n.info)
   result = emptyNode
  
-proc evalAssert(c: PEvalContext, n: PNode): PNode = 
-  result = evalAux(c, n.sons[1], {})
-  if isSpecial(result): return 
-  if getOrdValue(result) != 0: result = emptyNode
-  else: stackTrace(c, n, errAssertionFailed)
-  
 proc evalIncl(c: PEvalContext, n: PNode): PNode = 
   result = evalAux(c, n.sons[1], {efLValue})
   if isSpecial(result): return 
@@ -876,7 +870,6 @@ proc evalMagicOrCall(c: PEvalContext, n: PNode): PNode =
   of mOf: result = evalOf(c, n)
   of mSizeOf: result = raiseCannotEval(c, n)
   of mHigh: result = evalHigh(c, n)
-  of mAssert: result = evalAssert(c, n)
   of mExit: result = evalExit(c, n)
   of mNew, mNewFinalize: result = evalNew(c, n)
   of mNewSeq: result = evalNewSeq(c, n)

compiler/sem.nim

@@ -14,7 +14,7 @@ import
   wordrecg, ropes, msgs, os, condsyms, idents, renderer, types, platform, math,
   magicsys, parser, nversion, semdata, nimsets, semfold, importer,
   procfind, lookups, rodread, pragmas, passes, semtypinst, sigmatch, suggest,
-  semthreads, intsets, transf, evals, idgen
+  semthreads, intsets, transf, evals, idgen, aliases
 
 proc semPass*(): TPass
 # implementation

compiler/semexprs.nim

@@ -453,6 +453,14 @@ proc analyseIfAddressTakenInCall(c: PContext, n: PNode) =
         skipTypes(t.sons[i], abstractInst).kind == tyVar:
       n.sons[i] = analyseIfAddressTaken(c, n.sons[i])
   
+
+proc expectStringArg(c: PContext, n: PNode, i: int): PNode =
+  result = c.semAndEvalConstExpr(n.sons[i+1])
+  if result.kind notin {nkStrLit, nkRStrLit, nkTripleStrLit}:
+    GlobalError(result.info, errStringLiteralExpected)
+  
+include semmagic
+
 proc semDirectCallAnalyseEffects(c: PContext, n: PNode,
                                  flags: TExprFlags): PNode =
   if efWantIterator in flags:
@@ -520,6 +528,8 @@ proc semIndirectOp(c: PContext, n: PNode, flags: TExprFlags): PNode =
                   renderTree(n, {renderNoComments}))
   fixAbstractType(c, result)
   analyseIfAddressTakenInCall(c, result)
+  if result.sons[0].kind == nkSym and result.sons[0].sym.magic != mNone:
+    result = magicsAfterOverloadResolution(c, result, flags)
 
 proc semDirectOp(c: PContext, n: PNode, flags: TExprFlags): PNode = 
   # this seems to be a hotspot in the compiler!
@@ -530,6 +540,8 @@ proc semDirectOp(c: PContext, n: PNode, flags: TExprFlags): PNode =
     if result == nil: GlobalError(n.Info, errGenerated, getNotFoundError(c, n))
   fixAbstractType(c, result)
   analyseIfAddressTakenInCall(c, result)
+  if result.sons[0].sym.magic != mNone:
+    result = magicsAfterOverloadResolution(c, result, flags)
 
 proc buildStringify(c: PContext, arg: PNode): PNode = 
   if arg.typ != nil and skipTypes(arg.typ, abstractInst).kind == tyString:
@@ -914,12 +926,6 @@ proc setMs(n: PNode, s: PSym): PNode =
   n.sons[0] = newSymNode(s)
   n.sons[0].info = n.info
 
-proc expectStringArg(c: PContext, n: PNode, i: int): PNode =
-  result = c.semAndEvalConstExpr(n.sons[i+1])
-
-  if result.kind notin {nkStrLit, nkRStrLit, nkTripleStrLit}:
-    GlobalError(result.info, errStringLiteralExpected)
-
 proc expectMacroOrTemplateCall(c: PContext, n: PNode): PSym =
   ## The argument to the proc should be nkCall(...) or similar
   ## Returns the macro/template symbol
@@ -954,21 +960,6 @@ proc semExpandToAst(c: PContext, n: PNode, magicSym: PSym,
   else:
     result = semDirectOp(c, n, flags)
 
-proc semSlurp(c: PContext, n: PNode, flags: TExprFlags): PNode = 
-  if sonsLen(n) == 2:
-    var a = expectStringArg(c, n, 0)
-    try:
-      var filename = a.strVal.FindFile
-      var content = readFile(filename)
-      result = newStrNode(nkStrLit, content)
-      result.typ = getSysType(tyString)
-      result.info = n.info
-      c.slurpedFiles.add(filename)
-    except EIO:
-      GlobalError(a.info, errCannotOpenFile, a.strVal)
-  else:
-    result = semDirectOp(c, n, flags)
-
 proc semMagic(c: PContext, n: PNode, s: PSym, flags: TExprFlags): PNode = 
   # this is a hotspot in the compiler!
   result = n
@@ -991,7 +982,6 @@ proc semMagic(c: PContext, n: PNode, s: PSym, flags: TExprFlags): PNode =
       result = semAsgn(c, result)
     else:
       result = semDirectOp(c, n, flags)
-  of mSlurp: result = semSlurp(c, n, flags)
   of mExpandToAst: result = semExpandToAst(c, n, s, flags)
   of mAstToStr:
     if sonsLen(n) == 2:

compiler/semfold.nim

@@ -204,7 +204,7 @@ proc evalOp(m: TMagic, n, a, b, c: PNode): PNode =
     result = newIntNodeT(Ord(
       testCompileOptionArg(getStr(a), getStr(b), n.info)), n)
   of mNewString, mNewStringOfCap, 
-     mExit, mInc, ast.mDec, mEcho, mAssert, mSwap, mAppendStrCh, 
+     mExit, mInc, ast.mDec, mEcho, mSwap, mAppendStrCh, 
      mAppendStrStr, mAppendSeqElem, mSetLengthStr, mSetLengthSeq, 
      mParseExprToAst, mParseStmtToAst, mExpandToAst,
      mNLen..mNError, mEqRef: 

compiler/semmagic.nim

@@ -0,0 +1,36 @@
+#
+#
+#           The Nimrod Compiler
+#        (c) Copyright 2011 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# This include file implements the semantic checking for magics.
+
+proc semIsPartOf(c: PContext, n: PNode, flags: TExprFlags): PNode =
+  var r = isPartOf(n[1], n[2])
+  result = newIntNodeT(ord(r), n)
+  
+proc semSlurp(c: PContext, n: PNode, flags: TExprFlags): PNode = 
+  assert sonsLen(n) == 2
+  var a = expectStringArg(c, n, 0)
+  try:
+    var filename = a.strVal.FindFile
+    var content = readFile(filename)
+    result = newStrNode(nkStrLit, content)
+    result.typ = getSysType(tyString)
+    result.info = n.info
+    c.slurpedFiles.add(filename)
+  except EIO:
+    GlobalError(a.info, errCannotOpenFile, a.strVal)
+
+proc magicsAfterOverloadResolution(c: PContext, n: PNode, 
+                                   flags: TExprFlags): PNode =
+  case n[0].sym.magic
+  of mSlurp: result = semSlurp(c, n, flags)
+  of mIsPartOf: result = semIsPartOf(c, n, flags)
+  else: result = n
+  
+

compiler/types.nim

@@ -1024,7 +1024,6 @@ proc computeSize(typ: PType): biggestInt =
 proc getReturnType*(s: PSym): PType =
   # Obtains the return type of a iterator/proc/macro/template
   assert s.kind in {skProc, skTemplate, skMacro, skIterator}
-  # XXX ask Zahary if this change broke something
   result = s.typ.sons[0]
 
 proc getSize(typ: PType): biggestInt = 

todo.txt

@@ -2,6 +2,7 @@ version 0.8.14
 ==============
 
 - find a proper bugfix for C compilers optimizing away stack roots
+- cleanup file path handling in the compiler
 - warning for implicit openArray -> varargs convention
 - implement explicit varargs; **but** ``len(varargs)`` problem remains! 
   --> solve by implicit conversion from varargs to openarray
@@ -124,7 +125,6 @@ Low priority
     need to recompile clients; er ... what about templates, macros or anything
     that has inlining semantics?
 - codegen should use "NIM_CAST" macro and respect aliasing rules for GCC
-- remove unused mAssert magic
 
 Version 2
 =========