Fix.

Author: ncruces

sqlite3/libc/libc.wat

@@ -142,38 +142,42 @@
   (local $3 i32)
   (local $4 i32)
   (local $5 i32)
-  (local $6 i32)
+  (local $6 v128)
   (local $7 v128)
-  (local $8 v128)
-  (local $scratch i32)
-  (block $block
-   (br_if $block
-    (i32.eqz
-     (local.get $2)
+  (block $block2
+   (block $block
+    (br_if $block
+     (i32.eqz
+      (local.get $2)
+     )
     )
-   )
-   (local.set $4
-    (i32.and
-     (local.get $0)
-     (i32.const 15)
+    (local.set $3
+     (i32.and
+      (local.get $0)
+      (i32.const 15)
+     )
+    )
+    (local.set $4
+     (i32.sub
+      (local.get $2)
+      (i32.const 1)
+     )
     )
-   )
-   (block $block2
     (block $block1
      (br_if $block1
       (i32.eqz
        (v128.any_true
-        (local.tee $7
+        (local.tee $6
          (i8x16.eq
           (v128.load
-           (local.tee $3
+           (local.tee $2
             (i32.and
              (local.get $0)
              (i32.const -16)
             )
            )
           )
-          (local.tee $8
+          (local.tee $7
            (i8x16.splat
             (local.get $1)
            )
@@ -188,123 +192,109 @@
        (local.tee $5
         (i32.and
          (i8x16.bitmask
-          (local.get $7)
+          (local.get $6)
          )
          (i32.shl
           (i32.const -1)
-          (local.get $4)
+          (local.get $3)
          )
         )
        )
       )
      )
      (local.set $1
-      (local.get $2)
+      (local.get $4)
      )
      (br $block2)
     )
     (br_if $block
-     (i32.lt_u
-      (local.get $2)
+     (i32.gt_u
       (local.tee $1
        (i32.sub
-        (local.get $2)
-        (local.tee $3
-         (i32.sub
-          (i32.const 16)
-          (local.get $4)
-         )
+        (i32.add
+         (local.get $3)
+         (local.get $4)
         )
+        (i32.const 16)
        )
       )
+      (local.get $4)
      )
     )
-    (br_if $block
-     (i32.eqz
-      (local.get $1)
-     )
-    )
-    (local.set $3
+    (local.set $2
      (i32.add
-      (local.get $0)
-      (local.get $3)
+      (i32.sub
+       (local.get $0)
+       (local.get $3)
+      )
+      (i32.const 16)
      )
     )
-    (block $block3
-     (loop $label
-      (br_if $block3
-       (v128.any_true
-        (local.tee $7
-         (i8x16.eq
-          (v128.load
-           (local.get $3)
-          )
-          (local.get $8)
+    (loop $label
+     (if
+      (v128.any_true
+       (local.tee $6
+        (i8x16.eq
+         (v128.load
+          (local.get $2)
          )
+         (local.get $7)
         )
        )
       )
-      (br_if $block
-       (i32.gt_u
-        (local.tee $0
-         (i32.sub
-          (local.get $1)
-          (i32.const 16)
-         )
+      (then
+       (local.set $5
+        (i8x16.bitmask
+         (local.get $6)
         )
-        (local.get $1)
        )
-      )
-      (local.set $3
-       (i32.add
-        (local.get $3)
-        (i32.const 16)
+       (local.set $3
+        (i32.const 0)
        )
+       (br $block2)
       )
-      (br_if $label
-       (i32.eqz
-        (block (result i32)
-         (local.set $scratch
-          (i32.eq
-           (local.get $1)
-           (i32.const 16)
-          )
-         )
-         (local.set $1
-          (local.get $0)
-         )
-         (local.get $scratch)
+     )
+     (local.set $2
+      (i32.add
+       (local.get $2)
+       (i32.const 16)
+      )
+     )
+     (br_if $label
+      (i32.ge_u
+       (local.get $1)
+       (local.tee $1
+        (i32.sub
+         (local.get $1)
+         (i32.const 16)
         )
        )
       )
      )
-     (br $block)
     )
-    (local.set $5
-     (i8x16.bitmask
-      (local.get $7)
+   )
+   (return
+    (i32.const 0)
+   )
+  )
+  (select
+   (i32.add
+    (local.get $2)
+    (local.tee $0
+     (i32.ctz
+      (local.get $5)
      )
     )
    )
-   (local.set $6
-    (select
-     (i32.add
-      (local.get $3)
-      (local.tee $0
-       (i32.ctz
-        (local.get $5)
-       )
-      )
-     )
-     (i32.const 0)
-     (i32.lt_u
-      (local.get $0)
-      (local.get $1)
-     )
+   (i32.const 0)
+   (i32.le_u
+    (local.get $0)
+    (i32.add
+     (local.get $1)
+     (local.get $3)
     )
    )
   )
-  (local.get $6)
  )
  (func $strlen (param $0 i32) (result i32)
   (local $1 i32)

sqlite3/libc/string.h

@@ -71,18 +71,22 @@ int memcmp(const void *v1, const void *v2, size_t n) {
 
 __attribute__((weak))
 void *memchr(const void *v, int c, size_t n) {
+  if (n-- == 0) {
+    return NULL;
+  }
+
   uintptr_t align = (uintptr_t)v % sizeof(v128_t);
   const v128_t *w = (void *)(v - align);
   const v128_t wc = wasm_i8x16_splat(c);
 
-  while (n) {
+  while (true) {
     const v128_t cmp = wasm_i8x16_eq(*w, wc);
     if (wasm_v128_any_true(cmp)) {
       int mask = wasm_i8x16_bitmask(cmp) >> align << align;
       __builtin_assume(mask || align);
       if (mask) {
         size_t ctz = __builtin_ctz(mask);
-        return ctz < n ? (void *)w + ctz : NULL;
+        return ctz <= n + align ? (void *)w + ctz : NULL;
       }
     }
     if (__builtin_sub_overflow(n, sizeof(v128_t) - align, &n)) {
@@ -91,7 +95,6 @@ void *memchr(const void *v, int c, size_t n) {
     align = 0;
     w++;
   }
-  return NULL;
 }
 
 __attribute__((weak))
@@ -244,6 +247,7 @@ size_t strspn(const char *s, const char *c) {
   volatile v128_t *w = (void *)byteset;
 #pragma unroll
   for (size_t i = sizeof(byteset) / sizeof(v128_t); i--;) w[i] = (v128_t){};
+
   while (*c && (byteset[*(uint8_t *)c] = 1)) c++;
 #pragma unroll 4
   while (byteset[*(uint8_t *)s]) s++;
@@ -263,6 +267,7 @@ size_t strcspn(const char *s, const char *c) {
   volatile v128_t *w = (void *)byteset;
 #pragma unroll
   for (size_t i = sizeof(byteset) / sizeof(v128_t); i--;) w[i] = (v128_t){};
+
   while ((byteset[*(uint8_t *)c] = 1) && *c) c++;
 #pragma unroll 4
   while (!byteset[*(uint8_t *)s]) s++;