refactor pointerBitmap()

compiler/src/dmd/toobj.d

@@ -36,6 +36,7 @@ import dmd.dstruct;
 import dmd.dsymbol;
 import dmd.dtemplate;
 import dmd.errors;
+import dmd.errorsink;
 import dmd.expression;
 import dmd.func;
 import dmd.globals;
@@ -248,18 +249,18 @@ void write_instance_pointers(Type type, Symbol *s, uint offset)
         return;
 
     Array!(ulong) data;
-    ulong sz = getTypePointerBitmap(Loc.initial, type, &data);
+    const ulong sz = getTypePointerBitmap(Loc.initial, type, data, global.errorSink);
     if (sz == ulong.max)
         return;
 
     const bytes_size_t = cast(size_t)Type.tsize_t.size(Loc.initial);
     const bits_size_t = bytes_size_t * 8;
     auto words = cast(size_t)(sz / bytes_size_t);
-    for (size_t i = 0; i < data.length; i++)
+    foreach (i, const element; data[])
     {
         size_t bits = words < bits_size_t ? words : bits_size_t;
-        for (size_t b = 0; b < bits; b++)
-            if (data[i] & (1L << b))
+        foreach (size_t b; 0 .. bits)
+            if (element & (1L << b))
             {
                 auto off = cast(uint) ((i * bits_size_t + b) * bytes_size_t);
                 objmod.write_pointerRef(s, off + offset);

compiler/src/dmd/traits.d

@@ -32,6 +32,7 @@ import dmd.dsymbol;
 import dmd.dsymbolsem;
 import dmd.dtemplate;
 import dmd.errors;
+import dmd.errorsink;
 import dmd.expression;
 import dmd.expressionsem;
 import dmd.func;
@@ -92,44 +93,50 @@ private Dsymbol getDsymbolWithoutExpCtx(RootObject oarg)
 }
 
 /**
- * get an array of size_t values that indicate possible pointer words in memory
- *  if interpreted as the type given as argument
- * Returns: the size of the type in bytes, ulong.max on error
+ * Fill an array of target size_t values that indicate possible pointer words in memory
+ *  if interpreted as the type given as argument.
+ *  One bit in the array per pointer-sized piece of memory
+ * Params:
+ *      loc = location for error messages
+ *      t = type to generate pointer bitmap from
+ *      data = array forming the bitmap
+ *      eSink = error message sink
+ * Returns:
+ *      size of the type `t` in bytes, ulong.max on error
  */
-ulong getTypePointerBitmap(Loc loc, Type t, Array!(ulong)* data)
+ulong getTypePointerBitmap(Loc loc, Type t, ref Array!(ulong) data, ErrorSink eSink)
 {
-    ulong sz;
     auto tc = t.isTypeClass();
-    if (tc && !tc.sym.isInterfaceDeclaration())
-        sz = tc.sym.AggregateDeclaration.size(loc);
-    else
-        sz = t.size(loc);
+    const ulong sz = (tc && !tc.sym.isInterfaceDeclaration())
+        ? tc.sym.AggregateDeclaration.size(loc)
+        : t.size(loc);
     if (sz == SIZE_INVALID)
         return ulong.max;
 
-    const sz_size_t = Type.tsize_t.size(loc);
+    const sz_size_t = Type.tsize_t.size(loc); // size of target's size_t
+    assert(sz_size_t <= ulong.sizeof);
     if (sz > sz.max - sz_size_t)
     {
-        error(loc, "size overflow for type `%s`", t.toChars());
+        eSink.error(loc, "size overflow for type `%s`", t.toChars());
         return ulong.max;
     }
 
-    ulong bitsPerWord = sz_size_t * 8;
-    ulong cntptr = (sz + sz_size_t - 1) / sz_size_t;
-    ulong cntdata = (cntptr + bitsPerWord - 1) / bitsPerWord;
+    const ulong bitsPerElement = sz_size_t * 8;  // bits used in each array element
+    const ulong cntptr = (sz + sz_size_t - 1) / sz_size_t; // pointers have same size as sz_size_t
+    const ulong length = (cntptr + bitsPerElement - 1) / bitsPerElement; // a bit per pointer
 
-    data.setDim(cast(size_t)cntdata);
+    data.setDim(cast(size_t)length);
     data.zero();
 
     ulong offset;
-    bool error;
+    bool error;    // sticky error indicator
 
     void visit(Type t)
     {
         void setpointer(ulong off)
         {
             ulong ptroff = off / sz_size_t;
-            (*data)[cast(size_t)(ptroff / (8 * sz_size_t))] |= 1L << (ptroff % (8 * sz_size_t));
+            data[cast(size_t)(ptroff / bitsPerElement)] |= 1L << (ptroff % bitsPerElement);
         }
 
         void visitType(Type t)
@@ -282,28 +289,28 @@ ulong getTypePointerBitmap(Loc loc, Type t, Array!(ulong)* data)
  *
  *  Returns: [T.sizeof, pointerbit0-31/63, pointerbit32/64-63/128, ...]
  */
-private Expression pointerBitmap(TraitsExp e)
+private Expression pointerBitmap(TraitsExp e, ErrorSink eSink)
 {
     if (!e.args || e.args.length != 1)
     {
-        error(e.loc, "a single type expected for trait pointerBitmap");
+        eSink.error(e.loc, "a single type expected for trait pointerBitmap");
         return ErrorExp.get();
     }
 
     Type t = getType((*e.args)[0]);
     if (!t)
     {
-        error(e.loc, "`%s` is not a type", (*e.args)[0].toChars());
+        eSink.error(e.loc, "`%s` is not a type", (*e.args)[0].toChars());
         return ErrorExp.get();
     }
 
     Array!(ulong) data;
-    ulong sz = getTypePointerBitmap(e.loc, t, &data);
+    const ulong sz = getTypePointerBitmap(e.loc, t, data, eSink);
     if (sz == ulong.max)
         return ErrorExp.get();
 
     auto exps = new Expressions(data.length + 1);
-    (*exps)[0] = new IntegerExp(e.loc, sz, Type.tsize_t);
+    (*exps)[0] = new IntegerExp(e.loc, sz, Type.tsize_t);       // [0] is size in bytes of t
     foreach (size_t i; 1 .. exps.length)
         (*exps)[i] = new IntegerExp(e.loc, data[cast(size_t) (i - 1)], Type.tsize_t);
 
@@ -1871,7 +1878,7 @@ Expression semanticTraits(TraitsExp e, Scope* sc)
     }
     if (e.ident == Id.getPointerBitmap)
     {
-        return pointerBitmap(e);
+        return pointerBitmap(e, global.errorSink);
     }
     if (e.ident == Id.initSymbol)
     {