Fix big endian serialization

Big endian serialization was broken because:
- it partially relied on `WORDS_ENDIAN` (unconditionally undef'd in cutils.h)
- endianness was not handled at all in the bc reader.

Modifications:
- remove `WORDS_ENDIAN`
- use `bc_put_u32()` / `bc_put_u64()` in `JS_WriteBigInt()`
- use `bc_get_u32()` / `bc_get_u64()` in `JS_ReadBigInt()`
- handle host endianness in `bc_get_u16()`, `bc_get_u32()`, `bc_get_u64()` and
  `JS_ReadFunctionBytecode()`

- handle optional littleEndian argument as specified in
  `js_dataview_getValue()` and `js_dataview_setValue()`

Author: chqrlie

cutils.h

@@ -28,9 +28,6 @@
 #include <stdlib.h>
 #include <inttypes.h>
 
-/* set if CPU is big endian */
-#undef WORDS_BIGENDIAN
-
 #define likely(x)       __builtin_expect(!!(x), 1)
 #define unlikely(x)     __builtin_expect(!!(x), 0)
 #define force_inline inline __attribute__((always_inline))

quickjs.c

@@ -34582,8 +34582,6 @@ typedef enum BCTagEnum {
     BC_TAG_OBJECT,
     BC_TAG_ARRAY,
     BC_TAG_BIG_INT,
-    BC_TAG_BIG_FLOAT,
-    BC_TAG_BIG_DECIMAL,
     BC_TAG_TEMPLATE_OBJECT,
     BC_TAG_FUNCTION_BYTECODE,
     BC_TAG_MODULE,
@@ -34593,24 +34591,21 @@ typedef enum BCTagEnum {
     BC_TAG_DATE,
     BC_TAG_OBJECT_VALUE,
     BC_TAG_OBJECT_REFERENCE,
+#ifdef CONFIG_BIGNUM
+    BC_TAG_BIG_FLOAT,
+    BC_TAG_BIG_DECIMAL,
+#endif
 } BCTagEnum;
 
 #ifdef CONFIG_BIGNUM
-#define BC_BASE_VERSION 2
+#define BC_VERSION 0x43
 #else
-#define BC_BASE_VERSION 1
-#endif
-#define BC_BE_VERSION 0x40
-#ifdef WORDS_BIGENDIAN
-#define BC_VERSION (BC_BASE_VERSION | BC_BE_VERSION)
-#else
-#define BC_VERSION BC_BASE_VERSION
+#define BC_VERSION 3
 #endif
 
 typedef struct BCWriterState {
     JSContext *ctx;
     DynBuf dbuf;
-    BOOL byte_swap : 8;
     BOOL allow_bytecode : 8;
     BOOL allow_sab : 8;
     BOOL allow_reference : 8;
@@ -34640,8 +34635,6 @@ static const char * const bc_tag_str[] = {
     "object",
     "array",
     "bigint",
-    "bigfloat",
-    "bigdecimal",
     "template",
     "function",
     "module",
@@ -34651,31 +34644,44 @@ static const char * const bc_tag_str[] = {
     "Date",
     "ObjectValue",
     "ObjectReference",
+#ifdef CONFIG_BIGNUM
+    "bigfloat",
+    "bigdecimal",
+#endif
 };
 #endif
 
+static inline BOOL is_be(void)
+{
+    union {
+        uint16_t a;
+        uint8_t  b;
+    } u = {0x100};
+    return u.b;
+}
+
 static void bc_put_u8(BCWriterState *s, uint8_t v)
 {
     dbuf_putc(&s->dbuf, v);
 }
 
 static void bc_put_u16(BCWriterState *s, uint16_t v)
 {
-    if (s->byte_swap)
+    if (is_be())
         v = bswap16(v);
     dbuf_put_u16(&s->dbuf, v);
 }
 
 static __maybe_unused void bc_put_u32(BCWriterState *s, uint32_t v)
 {
-    if (s->byte_swap)
+    if (is_be())
         v = bswap32(v);
     dbuf_put_u32(&s->dbuf, v);
 }
 
 static void bc_put_u64(BCWriterState *s, uint64_t v)
 {
-    if (s->byte_swap)
+    if (is_be())
         v = bswap64(v);
     dbuf_put(&s->dbuf, (uint8_t *)&v, sizeof(v));
 }
@@ -34845,7 +34851,7 @@ static int JS_WriteFunctionBytecode(BCWriterState *s,
         pos += len;
     }
 
-    if (s->byte_swap)
+    if (is_be())
         bc_byte_swap(bc_buf, bc_len);
 
     dbuf_put(&s->dbuf, bc_buf, bc_len);
@@ -34936,20 +34942,14 @@ static int JS_WriteBigNum(BCWriterState *s, JSValueConst obj)
             bc_put_leb128(s, len);
             /* always saved in byte based little endian representation */
             for(j = 0; j < n1; j++) {
-                dbuf_putc(&s->dbuf, v >> (j * 8));
+                bc_put_u8(s, v >> (j * 8));
             }
             for(; i < a->len; i++) {
                 limb_t v = a->tab[i];
 #if LIMB_BITS == 32
-#ifdef WORDS_BIGENDIAN
-                v = bswap32(v);
-#endif
-                dbuf_put_u32(&s->dbuf, v);
+                bc_put_u32(s, v);
 #else
-#ifdef WORDS_BIGENDIAN
-                v = bswap64(v);
-#endif
-                dbuf_put_u64(&s->dbuf, v);
+                bc_put_u64(s, v);
 #endif
             }
         } else {
@@ -34992,14 +34992,14 @@ static int JS_WriteBigNum(BCWriterState *s, JSValueConst obj)
                         v8 = d;
                         bpos = 1;
                     } else {
-                        dbuf_putc(&s->dbuf, v8 | (d << 4));
+                        bc_put_u8(s, v8 | (d << 4));
                         bpos = 0;
                     }
                 }
             }
             /* flush the last digit */
             if (bpos) {
-                dbuf_putc(&s->dbuf, v8);
+                bc_put_u8(s, v8);
             }
         }
     }
@@ -35412,15 +35412,10 @@ static int JS_WriteObjectAtoms(BCWriterState *s)
     JSRuntime *rt = s->ctx->rt;
     DynBuf dbuf1;
     int i, atoms_size;
-    uint8_t version;
 
     dbuf1 = s->dbuf;
     js_dbuf_init(s->ctx, &s->dbuf);
-
-    version = BC_VERSION;
-    if (s->byte_swap)
-        version ^= BC_BE_VERSION;
-    bc_put_u8(s, version);
+    bc_put_u8(s, BC_VERSION);
 
     bc_put_leb128(s, s->idx_to_atom_count);
     for(i = 0; i < s->idx_to_atom_count; i++) {
@@ -35453,8 +35448,6 @@ uint8_t *JS_WriteObject2(JSContext *ctx, size_t *psize, JSValueConst obj,
 
     memset(s, 0, sizeof(*s));
     s->ctx = ctx;
-    /* XXX: byte swapped output is untested */
-    s->byte_swap = ((flags & JS_WRITE_OBJ_BSWAP) != 0);
     s->allow_bytecode = ((flags & JS_WRITE_OBJ_BYTECODE) != 0);
     s->allow_sab = ((flags & JS_WRITE_OBJ_SAB) != 0);
     s->allow_reference = ((flags & JS_WRITE_OBJ_REFERENCE) != 0);
@@ -35575,33 +35568,45 @@ static int bc_get_u8(BCReaderState *s, uint8_t *pval)
 
 static int bc_get_u16(BCReaderState *s, uint16_t *pval)
 {
+    uint16_t v;
     if (unlikely(s->buf_end - s->ptr < 2)) {
         *pval = 0; /* avoid warning */
         return bc_read_error_end(s);
     }
-    *pval = get_u16(s->ptr);
+    v = get_u16(s->ptr);
+    if (is_be())
+        v = bswap16(v);
+    *pval = v;
     s->ptr += 2;
     return 0;
 }
 
 static __maybe_unused int bc_get_u32(BCReaderState *s, uint32_t *pval)
 {
+    uint32_t v;
     if (unlikely(s->buf_end - s->ptr < 4)) {
         *pval = 0; /* avoid warning */
         return bc_read_error_end(s);
     }
-    *pval = get_u32(s->ptr);
+    v = get_u32(s->ptr);
+    if (is_be())
+        v = bswap32(v);
+    *pval = v;
     s->ptr += 4;
     return 0;
 }
 
 static int bc_get_u64(BCReaderState *s, uint64_t *pval)
 {
+    uint64_t v;
     if (unlikely(s->buf_end - s->ptr < 8)) {
         *pval = 0; /* avoid warning */
         return bc_read_error_end(s);
     }
-    *pval = get_u64(s->ptr);
+    v = get_u64(s->ptr);
+    if (is_be())
+        v = bswap64(v);
+    *pval = v;
     s->ptr += 8;
     return 0;
 }
@@ -35711,10 +35716,15 @@ static JSString *JS_ReadString(BCReaderState *s)
         js_free_string(s->ctx->rt, p);
         return NULL;
     }
-    // XXX: potential endianness issue
     memcpy(p->u.str8, s->ptr, size);
     s->ptr += size;
-    if (!is_wide_char) {
+    if (is_wide_char) {
+        if (is_be()) {
+            uint32_t i;
+            for (i = 0; i < len; i++)
+                p->u.str16[i] = bswap16(p->u.str16[i]);
+        }
+    } else {
         p->u.str8[size] = '\0'; /* add the trailing zero for 8 bit strings */
     }
 #ifdef DUMP_READ_OBJECT
@@ -35753,6 +35763,9 @@ static int JS_ReadFunctionBytecode(BCReaderState *s, JSFunctionBytecode *b,
     }
     b->byte_code_buf = bc_buf;
 
+    if (is_be())
+        bc_byte_swap(bc_buf, bc_len);
+
     pos = 0;
     while (pos < bc_len) {
         op = bc_buf[pos];
@@ -35873,15 +35886,9 @@ static JSValue JS_ReadBigNum(BCReaderState *s, int tag)
 #if LIMB_BITS == 32
                 if (bc_get_u32(s, &v))
                     goto fail;
-#ifdef WORDS_BIGENDIAN
-                v = bswap32(v);
-#endif
 #else
                 if (bc_get_u64(s, &v))
                     goto fail;
-#ifdef WORDS_BIGENDIAN
-                v = bswap64(v);
-#endif
 #endif
                 a->tab[i] = v;
             }
@@ -36589,7 +36596,6 @@ static int JS_ReadObjectAtoms(BCReaderState *s)
 
     if (bc_get_u8(s, &v8))
         return -1;
-    /* XXX: could support byte swapped input */
     if (v8 != BC_VERSION) {
         JS_ThrowSyntaxError(s->ctx, "invalid version (%d expected=%d)",
                             v8, BC_VERSION);
@@ -54857,12 +54863,9 @@ static JSValue js_dataview_getValue(JSContext *ctx,
     size = 1 << typed_array_size_log2(class_id);
     if (JS_ToIndex(ctx, &pos, argv[0]))
         return JS_EXCEPTION;
-    is_swap = FALSE;
+    is_swap = TRUE;
     if (argc > 1)
-        is_swap = JS_ToBool(ctx, argv[1]);
-#ifndef WORDS_BIGENDIAN
-    is_swap ^= 1;
-#endif
+        is_swap = !JS_ToBool(ctx, argv[1]);
     abuf = ta->buffer->u.array_buffer;
     if (abuf->detached)
         return JS_ThrowTypeErrorDetachedArrayBuffer(ctx);
@@ -54986,12 +54989,9 @@ static JSValue js_dataview_setValue(JSContext *ctx,
             v64 = u.u64;
         }
     }
-    is_swap = FALSE;
+    is_swap = TRUE;
     if (argc > 2)
-        is_swap = JS_ToBool(ctx, argv[2]);
-#ifndef WORDS_BIGENDIAN
-    is_swap ^= 1;
-#endif
+        is_swap = !JS_ToBool(ctx, argv[2]);
     abuf = ta->buffer->u.array_buffer;
     if (abuf->detached)
         return JS_ThrowTypeErrorDetachedArrayBuffer(ctx);