Remove undefined behaviors

Author: jart

libc/fmt/fmt.c

@@ -612,7 +612,7 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
           if (pun.d && prec < 13) {
             pun.u[1] |= 0x100000;
             if (prec < 5) {
-              ui = 1 << ((5 - prec) * 4 - 1);
+              ui = 1u << ((5 - prec) * 4 - 1);
               if (pun.u[1] & ui) {
                 if (pun.u[1] & ((ui - 1) | (ui << 1)) || pun.u[0]) {
                   pun.u[1] += ui;
@@ -631,7 +631,7 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
               }
             } else {
               i1 = (13 - prec) * 4;
-              ui = 1 << (i1 - 1);
+              ui = 1u << (i1 - 1);
               if (pun.u[0] & ui && pun.u[0] & ((ui - 1) | (ui << 1))) {
                 pun.u[0] += ui;
                 if (!(pun.u[0] >> i1)) goto BumpIt;
@@ -640,12 +640,13 @@ hidden int __fmt(void *fn, void *arg, const char *format, va_list va) {
           }
         } else {
           if ((ui = pun.u[0])) {
-            for (prec = 6; (ui = (ui << 4) & 0xffffffff); ++prec) {
-            }
+            ui = __builtin_ctz(ui);
+            prec = 6 + ((32 - ROUNDDOWN(ui, 4)) >> 2) - 1;
+          } else if ((ui = pun.u[1] & 0xfffff)) {
+            ui = __builtin_ctz(ui);
+            prec = (20 - ROUNDDOWN(ui, 4)) >> 2;
           } else {
-            for (prec = 0, ui = pun.u[1] & 0xfffff; ui;
-                 ++prec, ui = (ui << 4) & 0xfffff) {
-            }
+            prec = 0;
           }
         }
         bw = 1;

libc/fmt/fmt.mk

@@ -68,11 +68,6 @@ o/$(MODE)/libc/fmt/filetimetotimeval.o:		\
 		OVERRIDE_CFLAGS +=		\
 			-O3
 
-o/$(MODE)/libc/fmt/itoa64radix10.greg.o		\
-o/$(MODE)/libc/fmt/itoa128radix10.greg.o:	\
-		OVERRIDE_CFLAGS +=		\
-			-fwrapv
-
 LIBC_FMT_LIBS = $(foreach x,$(LIBC_FMT_ARTIFACTS),$($(x)))
 LIBC_FMT_SRCS = $(foreach x,$(LIBC_FMT_ARTIFACTS),$($(x)_SRCS))
 LIBC_FMT_HDRS = $(foreach x,$(LIBC_FMT_ARTIFACTS),$($(x)_HDRS))

libc/fmt/itoa128radix10.greg.c

@@ -49,5 +49,5 @@ noinline size_t uint128toarray_radix10(uint128_t i, char *a) {
 size_t int128toarray_radix10(int128_t i, char *a) {
   if (i >= 0) return uint128toarray_radix10(i, a);
   *a++ = '-';
-  return 1 + uint128toarray_radix10(-i, a);
+  return 1 + uint128toarray_radix10(-(uint128_t)i, a);
 }

libc/fmt/itoa64.c

@@ -35,7 +35,7 @@ noinline size_t uint64toarray(uint64_t i, char *a, int r) {
 size_t int64toarray(int64_t i, char *a, int r) {
   if (i < 0) {
     *a++ = '-';
-    i = -i;
+    i = -(uint64_t)i;
   }
   return uint64toarray(i, a, r);
 }

libc/fmt/itoa64radix10.greg.c

@@ -27,14 +27,10 @@
  * @return bytes written w/o nul
  */
 noinline size_t uint64toarray_radix10(uint64_t i, char a[hasatleast 21]) {
-  size_t j;
-  j = 0;
+  size_t j = 0;
   do {
-    struct {
-      uint64_t q, r;
-    } x = {i / 10, i % 10};
-    a[j++] = x.r + '0';
-    i = x.q;
+    a[j++] = i % 10 + '0';
+    i = i / 10;
   } while (i > 0);
   a[j] = '\0';
   reverse(a, j);
@@ -49,5 +45,5 @@ noinline size_t uint64toarray_radix10(uint64_t i, char a[hasatleast 21]) {
 size_t int64toarray_radix10(int64_t i, char a[hasatleast 21]) {
   if (i >= 0) return uint64toarray_radix10(i, a);
   *a++ = '-';
-  return 1 + uint64toarray_radix10(-i, a);
+  return 1 + uint64toarray_radix10(-(uint64_t)i, a);
 }

libc/integral/c.inc

@@ -584,6 +584,13 @@ typedef uint64_t uintmax_t;
 #define noasan
 #endif
 
+#if (__GNUC__ + 0) * 100 + (__GNUC_MINOR__ + 0) >= 408 || \
+    __has_attribute(__no_sanitize_undefined__)
+#define noubsan __attribute__((__no_sanitize_undefined__))
+#else
+#define noubsan
+#endif
+
 #ifndef unreachable
 #if defined(__GNUC__) && !defined(__STRICT_ANSI__)
 #define unreachable __builtin_unreachable()

libc/intrin/asan.c

@@ -169,7 +169,7 @@ static void *__asan_memset(void *p, int c, size_t n) {
   size_t i;
   uint64_t x;
   b = p;
-  x = 0x0101010101010101 * (c & 255);
+  x = 0x0101010101010101ul * (c & 255);
   switch (n) {
     case 0:
       return p;

libc/intrin/intrin.mk

@@ -41,13 +41,11 @@ $(LIBC_INTRIN_A).pkg:					\
 		$(LIBC_INTRIN_A_OBJS)			\
 		$(foreach x,$(LIBC_INTRIN_A_DIRECTDEPS),$($(x)_A).pkg)
 
-$(LIBC_INTRIN_A_OBJS):					\
-		OVERRIDE_CFLAGS +=			\
-			$(NO_MAGIC)			\
-			-O3
-
-o/$(MODE)/libc/intrin/asan.o:				\
+o/$(MODE)/libc/intrin/asan.o				\
+o/$(MODE)/libc/intrin/ubsan.o:				\
 		OVERRIDE_CFLAGS +=			\
+			-fno-sanitize=all		\
+			-fno-stack-protector		\
 			-mgeneral-regs-only		\
 			-O2
 

libc/intrin/pabsd.c

@@ -28,7 +28,7 @@ void(pabsd)(uint32_t a[4], const int32_t b[4]) {
   unsigned i;
   uint32_t r[4];
   for (i = 0; i < 4; ++i) {
-    r[i] = ABS(b[i]);
+    r[i] = b[i] >= 0 ? b[i] : -(uint32_t)b[i];
   }
   memcpy(a, r, 16);
 }

libc/intrin/paddd.c

@@ -27,9 +27,11 @@
  * @param 𝑐 [r/o] supplies second input vector
  * @mayalias
  */
-void(paddd)(int32_t a[4], const int32_t b[4], const int32_t c[4]) {
+void(paddd)(uint32_t a[4], const uint32_t b[4], const uint32_t c[4]) {
   unsigned i;
-  int32_t r[4];
-  for (i = 0; i < 4; ++i) r[i] = b[i] + c[i];
+  uint32_t r[4];
+  for (i = 0; i < 4; ++i) {
+    r[i] = b[i] + c[i];
+  }
   memcpy(a, r, 16);
 }