unsuccessful phantom bug hunting

compiler/ccgstmts.nim

@@ -319,8 +319,14 @@ proc genStringCase(p: BProc, t: PNode) =
         # but we reserved a label, which we use later
     appcg(p, cpsStmts, "switch (#hashString($1) & $2) {$n", 
          [rdLoc(a), toRope(bitMask)])
-    for j in countup(0, high(branches)): 
+    for j in countup(0, high(branches)):
-      if branches[j] != nil: 
+      when false:
+        let interior = cast[int](interiorAllocatedPtr(addr(branches[0])))+
+                                 2*sizeof(pointer)
+        let brn = cast[int](cast[pointer](branches))
+        if interior != brn:
+          echo "BUG! ", interior, "-", brn
+      if branches[j] != nil:
         appf(p.s[cpsStmts], "case $1: $n$2break;$n", 
              [intLiteral(j), branches[j]])
     appf(p.s[cpsStmts], "}$n") # else statement:

lib/system.nim

@@ -808,9 +808,34 @@ when hasThreadSupport:
 else:
   {.pragma: rtlThreadVar.}
 
+const
+  QuitSuccess* = 0
+    ## is the value that should be passed to ``quit`` to indicate
+    ## success.
+
+  QuitFailure* = 1
+    ## is the value that should be passed to ``quit`` to indicate
+    ## failure.
+
+var program_result* {.exportc: "nim_$1".} = QuitSuccess
+  ## modify this varialbe to specify the exit code of the program
+  ## under normal circumstances. when the program is terminated
+  ## prematurelly using ``quit``, this value is ignored.
+
+proc quit*(errorcode: int = QuitSuccess) {.
+  magic: "Exit", importc: "exit", noDecl, noReturn.}
+  ## stops the program immediately; before stopping the program the
+  ## "quit procedures" are called in the opposite order they were added
+  ## with ``addQuitProc``. ``quit`` never returns and ignores any
+  ## exception that may have been raised by the quit procedures.
+  ## It does *not* call the garbage collector to free all the memory,
+  ## unless a quit procedure calls ``GC_collect``.
+
 template sysAssert(cond, msg: expr) =
   # change this to activate system asserts
-  #if not cond: echo "[SYSASSERT] ", msg
+  #if not cond: 
+  #  echo "[SYSASSERT] ", msg
+  #  quit 1
   nil
 
 include "system/inclrtl"
@@ -1530,29 +1555,6 @@ template newException*(exceptn, message: expr): expr =
     e.msg = message
     e
 
-const
-  QuitSuccess* = 0
-    ## is the value that should be passed to ``quit`` to indicate
-    ## success.
-
-  QuitFailure* = 1
-    ## is the value that should be passed to ``quit`` to indicate
-    ## failure.
-
-var program_result* {.exportc: "nim_$1".} = QuitSuccess
-  ## modify this varialbe to specify the exit code of the program
-  ## under normal circumstances. when the program is terminated
-  ## prematurelly using ``quit``, this value is ignored.
-
-proc quit*(errorcode: int = QuitSuccess) {.
-  magic: "Exit", importc: "exit", noDecl, noReturn.}
-  ## stops the program immediately; before stopping the program the
-  ## "quit procedures" are called in the opposite order they were added
-  ## with ``addQuitProc``. ``quit`` never returns and ignores any
-  ## exception that may have been raised by the quit procedures.
-  ## It does *not* call the garbage collector to free all the memory,
-  ## unless a quit procedure calls ``GC_collect``.
-
 when not defined(EcmaScript) and not defined(NimrodVM):
   {.push stack_trace: off.}
 

lib/system/alloc.nim

@@ -479,14 +479,6 @@ proc getSmallChunk(a: var TMemRegion): PSmallChunk =
 
 # -----------------------------------------------------------------------------
 
-proc getCellSize(p: pointer): int {.inline.} = 
-  var c = pageAddr(p)
-  result = c.size
-  
-proc memSize(a: TMemRegion, p: pointer): int {.inline.} =
-  var c = pageAddr(p)
-  result = c.size
-    
 proc rawAlloc(a: var TMemRegion, requestedSize: int): pointer =
   sysAssert(roundup(65, 8) == 72, "rawAlloc 1")
   sysAssert requestedSize >= sizeof(TFreeCell), "rawAlloc 2"
@@ -526,6 +518,8 @@ proc rawAlloc(a: var TMemRegion, requestedSize: int): pointer =
       sysAssert((cast[TAddress](result) and (MemAlign-1)) == 0, "rawAlloc 9")
     if c.free < size:
       ListRemove(a.freeSmallChunks[s], c)
+    sysAssert(((cast[TAddress](result) and PageMask) -% smallChunkOverhead()) %%
+               size == 0, "rawAlloc 21")
   else:
     size = roundup(requestedSize+bigChunkOverhead(), PageSize)
     # allocate a large block
@@ -549,6 +543,8 @@ proc rawDealloc(a: var TMemRegion, p: pointer) =
     # `p` is within a small chunk:
     var c = cast[PSmallChunk](c)
     var s = c.size
+    sysAssert(((cast[TAddress](p) and PageMask) -% smallChunkOverhead()) %%
+               s == 0, "rawDealloc 3")
     var f = cast[ptr TFreeCell](p)
     #echo("setting to nil: ", $cast[TAddress](addr(f.zeroField)))
     sysAssert(f.zeroField != 0, "rawDealloc 1")
@@ -570,6 +566,8 @@ proc rawDealloc(a: var TMemRegion, p: pointer) =
         ListRemove(a.freeSmallChunks[s div memAlign], c)
         c.size = SmallChunkSize
         freeBigChunk(a, cast[PBigChunk](c))
+    sysAssert(((cast[TAddress](p) and PageMask) -% smallChunkOverhead()) %%
+               s == 0, "rawDealloc 2")
   else:
     # set to 0xff to check for usage after free bugs:
     when overwriteFree: c_memset(p, -1'i32, c.size -% bigChunkOverhead())
@@ -687,6 +685,9 @@ template InstantiateForRegion(allocator: expr) =
     proc interiorAllocatedPtr*(p: pointer): pointer =
       result = interiorAllocatedPtr(allocator, p)
 
+    proc isAllocatedPtr*(p: pointer): bool = 
+      result = isAllocatedPtr(allocator, p)
+
   proc deallocOsPages = deallocOsPages(allocator)
 
   proc alloc(size: int): pointer =

todo.txt

@@ -1,7 +1,7 @@
 version 0.8.14
 ==============
 
-- fix allocator bug
+- fix memory corruption bug triggered by visual c++ in release mode
 - fix line info in assertions
 
 version 0.9.0