fix Issue 15019 - [ICE] Heisencrash on OS X 32-bit with non-trivial p…

…rojects

src/backend/elfobj.c

@@ -2425,8 +2425,7 @@ unsigned Obj::bytes(int seg, targ_size_t offset, unsigned nbytes, void *p)
     int save = buf->size();
     //dbg_printf("Obj::bytes(seg=%d, offset=x%lx, nbytes=%d, p=x%x)\n",
             //seg,offset,nbytes,p);
-    buf->setsize(offset);
-    buf->reserve(nbytes);
+    buf->position(offset, nbytes);
     if (p)
     {
         buf->writen(p,nbytes);

src/backend/machobj.c

@@ -2285,8 +2285,7 @@ if (!buf) halt();
     int save = buf->size();
     //dbg_printf("Obj::bytes(seg=%d, offset=x%lx, nbytes=%d, p=x%x)\n",
             //seg,offset,nbytes,p);
-    buf->setsize(offset);
-    buf->reserve(nbytes);
+    buf->position(offset, nbytes);
     if (p)
     {
         buf->writen(p,nbytes);
@@ -2574,7 +2573,7 @@ int Obj::reftoident(int seg, targ_size_t offset, Symbol *s, targ_size_t val,
 
         Outbuffer *buf = SegData[seg]->SDbuf;
         int save = buf->size();
-        buf->setsize(offset);
+        buf->position(offset, retsize);
         //printf("offset = x%llx, val = x%llx\n", offset, val);
         if (retsize == 8)
             buf->write64(val);

src/backend/outbuf.c

@@ -24,6 +24,8 @@
 #if DEBUG
 static char __file__[] = __FILE__;      // for tassert.h
 #include        "tassert.h"
+#else
+#include        <assert.h>
 #endif
 
 Outbuffer::Outbuffer()
@@ -107,23 +109,25 @@ void Outbuffer::enlarge(size_t nbytes)
     p = buf + used;
 }
 
-// Position buffer for output at a specified location and size.
-//      If data will extend buffer size, reserve space
-//      If data will rewrite existing data
-//              position for write and return previous buffer size
-//
-//      If data will append to buffer
-//              position for write and return new size
-size_t Outbuffer::position(size_t pos, size_t nbytes)
+/*****************************************
+ * Position buffer for output at a specified location and size.
+ * Params:
+ *      offset = specified location
+ *      nbytes = number of bytes to be written at offset
+ */
+void Outbuffer::position(size_t offset, size_t nbytes)
 {
-    size_t current_sz = size();
-    unsigned char *fend = buf+pos+nbytes;       // future end of buffer
-    if (fend >= pend)
+    if (offset + nbytes > len)
     {
-        reserve (fend - pend);
+        enlarge(offset + nbytes - (p - buf));
     }
-    setsize(pos);
-    return pos+nbytes > current_sz ? pos+nbytes : current_sz;
+    p = buf + offset;
+#if DEBUG
+    assert(buf <= p);
+    assert(p <= pend);
+    assert(len == pend - buf);
+    assert(p + nbytes <= pend);
+#endif
 }
 
 // Write an array to the buffer.
@@ -264,6 +268,11 @@ char *Outbuffer::toString()
 void Outbuffer::setsize(size_t size)
 {
     p = buf + size;
+#if DEBUG
+    assert(buf <= p);
+    assert(p <= pend);
+    assert(len == pend - buf);
+#endif
 }
 
 void Outbuffer::writesLEB128(int value)

src/backend/outbuf.h

@@ -51,7 +51,7 @@ struct Outbuffer
     void *writezeros(size_t n);
 
     // Position buffer to accept the specified number of bytes at offset
-    size_t position(size_t offset, size_t nbytes);
+    void position(size_t offset, size_t nbytes);
 
     // Write an array to the buffer, no reserve check
     void writen(const void *b, size_t len)

test/compilable/test15019.d

@@ -0,0 +1,74 @@
+// https://issues.dlang.org/show_bug.cgi?id=15019
+// dmd -m32 -c all.d
+
+import std.string;
+
+struct Color()
+{
+    static fromHex(char[] s)
+    {
+        import std.conv;
+        s.to!ubyte;
+    }
+}
+
+Color!() RGB    ;
+
+struct Matrix(T, int R, int C)
+{
+        Vector!(T, C) row_t;
+        T[C] v;        // all elements
+
+        /// Covnerts to pretty string.
+        string toString() const
+        {
+            try
+                return format("%s", v);
+            catch
+                assert(false); // should not happen since format is right
+        }
+}
+
+// GLSL is a big inspiration here
+// we defines types with more or less the same names
+template mat2x2(T) { Matrix!(T, 2, 2) mat2x2; }
+template mat3x3(T) { Matrix!(T, 3, 3) mat3x3; }
+template mat4x4(T) { Matrix!(T, 4, 4) mat4x4; }
+
+alias mat2x2 mat2;
+alias mat3x3 mat3;  // shorter names for most common matrices
+alias mat4x4 mat4;
+
+string definePostfixAliases(string type)
+{
+    return "alias " ~ type ~ "!byte "   ~ type ~ "b;\n"
+"alias " ~ type ~ "!ubyte "  ~ type ~ "ub;\n"
+"alias " ~ type ~ "!short "  ~ type ~ "s;\n"
+"alias " ~ type ~ "!ushort " ~ type ~ "us;\n"
+"alias " ~ type ~ "!int "    ~ type ~ "i;\n"
+"alias " ~ type ~ "!uint "   ~ type ~ "ui;\n"
+"alias " ~ type ~ "!long "   ~ type ~ "l;\n"
+"alias " ~ type ~ "!ulong "  ~ type ~ "ul;\n"
+"alias " ~ type ~ "!float "  ~ type ~ "f;\n"
+"alias " ~ type ~ "!double " ~ type ~ "d;\n";
+}
+
+// define a lot of type names
+mixin(definePostfixAliases("mat2"));
+mixin(definePostfixAliases("mat3"));
+mixin(definePostfixAliases("mat4"));
+import std.string;
+
+struct Vector(T, int N)
+{
+    T[N] v;
+
+    string toString()
+    {
+        try
+            return format("%s", v);
+        catch
+            assert(false);
+    }
+}
+