Fix "unsafe narrowing" warnings in absl, 2/n.

Addresses failures with the following, in some files:
-Wshorten-64-to-32
-Wimplicit-int-conversion
-Wsign-compare
-Wsign-conversion
-Wtautological-unsigned-zero-compare

(This specific CL focuses on .cc files in dirs a-h.)

Bug: chromium:1292951
PiperOrigin-RevId: 464541951
Change-Id: If23b63ccea8e9b730159ff1c7288e9300a40b6bd

absl/base/internal/low_level_alloc.cc

@@ -364,7 +364,7 @@ LowLevelAlloc::Arena::Arena(uint32_t flags_value)
 }
 
 // L < meta_data_arena->mu
-LowLevelAlloc::Arena *LowLevelAlloc::NewArena(int32_t flags) {
+LowLevelAlloc::Arena *LowLevelAlloc::NewArena(uint32_t flags) {
   Arena *meta_data_arena = DefaultArena();
 #ifndef ABSL_LOW_LEVEL_ALLOC_ASYNC_SIGNAL_SAFE_MISSING
   if ((flags & LowLevelAlloc::kAsyncSignalSafe) != 0) {

absl/base/internal/low_level_alloc.h

@@ -103,7 +103,7 @@ class LowLevelAlloc {
   // the provided flags.  For example, the call NewArena(kAsyncSignalSafe)
   // is itself async-signal-safe, as well as generatating an arena that provides
   // async-signal-safe Alloc/Free.
-  static Arena *NewArena(int32_t flags);
+  static Arena *NewArena(uint32_t flags);
 
   // Destroys an arena allocated by NewArena and returns true,
   // provided no allocated blocks remain in the arena.

absl/base/internal/raw_logging.cc

@@ -89,12 +89,14 @@ constexpr char kTruncated[] = " ... (message truncated)\n";
 bool VADoRawLog(char** buf, int* size, const char* format, va_list ap)
     ABSL_PRINTF_ATTRIBUTE(3, 0);
 bool VADoRawLog(char** buf, int* size, const char* format, va_list ap) {
-  int n = vsnprintf(*buf, *size, format, ap);
+  if (*size < 0)
+    return false;
+  int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
   bool result = true;
   if (n < 0 || n > *size) {
     result = false;
     if (static_cast<size_t>(*size) > sizeof(kTruncated)) {
-      n = *size - sizeof(kTruncated);  // room for truncation message
+      n = *size - static_cast<int>(sizeof(kTruncated));
     } else {
       n = 0;  // no room for truncation message
     }
@@ -116,9 +118,11 @@ constexpr int kLogBufSize = 3000;
 bool DoRawLog(char** buf, int* size, const char* format, ...)
     ABSL_PRINTF_ATTRIBUTE(3, 4);
 bool DoRawLog(char** buf, int* size, const char* format, ...) {
+  if (*size < 0)
+    return false;
   va_list ap;
   va_start(ap, format);
-  int n = vsnprintf(*buf, *size, format, ap);
+  int n = vsnprintf(*buf, static_cast<size_t>(*size), format, ap);
   va_end(ap);
   if (n < 0 || n > *size) return false;
   *size -= n;
@@ -206,7 +210,7 @@ void AsyncSignalSafeWriteToStderr(const char* s, size_t len) {
 #elif defined(ABSL_HAVE_POSIX_WRITE)
   write(STDERR_FILENO, s, len);
 #elif defined(ABSL_HAVE_RAW_IO)
-  _write(/* stderr */ 2, s, len);
+  _write(/* stderr */ 2, s, static_cast<unsigned>(len));
 #else
   // stderr logging unsupported on this platform
   (void) s;

absl/base/internal/strerror.cc

@@ -66,8 +66,8 @@ constexpr int kSysNerr = 135;
 
 std::array<std::string, kSysNerr>* NewStrErrorTable() {
   auto* table = new std::array<std::string, kSysNerr>;
-  for (int i = 0; i < static_cast<int>(table->size()); ++i) {
-    (*table)[i] = StrErrorInternal(i);
+  for (size_t i = 0; i < table->size(); ++i) {
+    (*table)[i] = StrErrorInternal(static_cast<int>(i));
   }
   return table;
 }
@@ -77,8 +77,8 @@ std::array<std::string, kSysNerr>* NewStrErrorTable() {
 std::string StrError(int errnum) {
   absl::base_internal::ErrnoSaver errno_saver;
   static const auto* table = NewStrErrorTable();
-  if (errnum >= 0 && errnum < static_cast<int>(table->size())) {
-    return (*table)[errnum];
+  if (errnum >= 0 && static_cast<size_t>(errnum) < table->size()) {
+    return (*table)[static_cast<size_t>(errnum)];
   }
   return StrErrorInternal(errnum);
 }

absl/base/internal/sysinfo.cc

@@ -117,7 +117,7 @@ int Win32NumCPUs() {
     }
   }
   free(info);
-  return logicalProcessorCount;
+  return static_cast<int>(logicalProcessorCount);
 }
 
 #endif
@@ -128,7 +128,7 @@ static int GetNumCPUs() {
 #if defined(__myriad2__)
   return 1;
 #elif defined(_WIN32)
-  const unsigned hardware_concurrency = Win32NumCPUs();
+  const int hardware_concurrency = Win32NumCPUs();
   return hardware_concurrency ? hardware_concurrency : 1;
 #elif defined(_AIX)
   return sysconf(_SC_NPROCESSORS_ONLN);

absl/debugging/failure_signal_handler.cc

@@ -291,7 +291,7 @@ static void WriteFailureInfo(int signo, void* ucontext, int cpu,
 // some platforms.
 static void PortableSleepForSeconds(int seconds) {
 #ifdef _WIN32
-  Sleep(seconds * 1000);
+  Sleep(static_cast<DWORD>(seconds * 1000));
 #else
   struct timespec sleep_time;
   sleep_time.tv_sec = seconds;
@@ -325,9 +325,9 @@ static void AbslFailureSignalHandler(int signo, siginfo_t*, void* ucontext) {
 
   const GetTidType this_tid = absl::base_internal::GetTID();
   GetTidType previous_failed_tid = 0;
-  if (!failed_tid.compare_exchange_strong(
-          previous_failed_tid, static_cast<intptr_t>(this_tid),
-          std::memory_order_acq_rel, std::memory_order_relaxed)) {
+  if (!failed_tid.compare_exchange_strong(previous_failed_tid, this_tid,
+                                          std::memory_order_acq_rel,
+                                          std::memory_order_relaxed)) {
     ABSL_RAW_LOG(
         ERROR,
         "Signal %d raised at PC=%p while already in AbslFailureSignalHandler()",

absl/debugging/internal/demangle.cc

@@ -151,12 +151,12 @@ static const AbbrevPair kSubstitutionList[] = {
 // State needed for demangling.  This struct is copied in almost every stack
 // frame, so every byte counts.
 typedef struct {
-  int mangled_idx;                   // Cursor of mangled name.
-  int out_cur_idx;                   // Cursor of output string.
-  int prev_name_idx;                 // For constructors/destructors.
-  signed int prev_name_length : 16;  // For constructors/destructors.
-  signed int nest_level : 15;        // For nested names.
-  unsigned int append : 1;           // Append flag.
+  int mangled_idx;                     // Cursor of mangled name.
+  int out_cur_idx;                     // Cursor of output string.
+  int prev_name_idx;                   // For constructors/destructors.
+  unsigned int prev_name_length : 16;  // For constructors/destructors.
+  signed int nest_level : 15;          // For nested names.
+  unsigned int append : 1;             // Append flag.
   // Note: for some reason MSVC can't pack "bool append : 1" into the same int
   // with the above two fields, so we use an int instead.  Amusingly it can pack
   // "signed bool" as expected, but relying on that to continue to be a legal
@@ -235,8 +235,8 @@ static size_t StrLen(const char *str) {
 }
 
 // Returns true if "str" has at least "n" characters remaining.
-static bool AtLeastNumCharsRemaining(const char *str, int n) {
-  for (int i = 0; i < n; ++i) {
+static bool AtLeastNumCharsRemaining(const char *str, size_t n) {
+  for (size_t i = 0; i < n; ++i) {
     if (str[i] == '\0') {
       return false;
     }
@@ -264,7 +264,7 @@ static void InitState(State *state, const char *mangled, char *out,
   state->parse_state.mangled_idx = 0;
   state->parse_state.out_cur_idx = 0;
   state->parse_state.prev_name_idx = 0;
-  state->parse_state.prev_name_length = -1;
+  state->parse_state.prev_name_length = 0;
   state->parse_state.nest_level = -1;
   state->parse_state.append = true;
 }
@@ -356,8 +356,8 @@ static bool ZeroOrMore(ParseFunc parse_func, State *state) {
 // Append "str" at "out_cur_idx".  If there is an overflow, out_cur_idx is
 // set to out_end_idx+1.  The output string is ensured to
 // always terminate with '\0' as long as there is no overflow.
-static void Append(State *state, const char *const str, const int length) {
-  for (int i = 0; i < length; ++i) {
+static void Append(State *state, const char *const str, const size_t length) {
+  for (size_t i = 0; i < length; ++i) {
     if (state->parse_state.out_cur_idx + 1 <
         state->out_end_idx) {  // +1 for '\0'
       state->out[state->parse_state.out_cur_idx++] = str[i];
@@ -420,7 +420,7 @@ static bool EndsWith(State *state, const char chr) {
 
 // Append "str" with some tweaks, iff "append" state is true.
 static void MaybeAppendWithLength(State *state, const char *const str,
-                                  const int length) {
+                                  const size_t length) {
   if (state->parse_state.append && length > 0) {
     // Append a space if the output buffer ends with '<' and "str"
     // starts with '<' to avoid <<<.
@@ -432,14 +432,14 @@ static void MaybeAppendWithLength(State *state, const char *const str,
     if (state->parse_state.out_cur_idx < state->out_end_idx &&
         (IsAlpha(str[0]) || str[0] == '_')) {
       state->parse_state.prev_name_idx = state->parse_state.out_cur_idx;
-      state->parse_state.prev_name_length = length;
+      state->parse_state.prev_name_length = static_cast<unsigned int>(length);
     }
     Append(state, str, length);
   }
 }
 
 // Appends a positive decimal number to the output if appending is enabled.
-static bool MaybeAppendDecimal(State *state, unsigned int val) {
+static bool MaybeAppendDecimal(State *state, int val) {
   // Max {32-64}-bit unsigned int is 20 digits.
   constexpr size_t kMaxLength = 20;
   char buf[kMaxLength];
@@ -456,7 +456,7 @@ static bool MaybeAppendDecimal(State *state, unsigned int val) {
     } while (p > buf && val != 0);
 
     // 'p' landed on the last character we set.  How convenient.
-    Append(state, p, kMaxLength - (p - buf));
+    Append(state, p, kMaxLength - static_cast<size_t>(p - buf));
   }
 
   return true;
@@ -466,7 +466,7 @@ static bool MaybeAppendDecimal(State *state, unsigned int val) {
 // Returns true so that it can be placed in "if" conditions.
 static bool MaybeAppend(State *state, const char *const str) {
   if (state->parse_state.append) {
-    int length = StrLen(str);
+    size_t length = StrLen(str);
     MaybeAppendWithLength(state, str, length);
   }
   return true;
@@ -521,10 +521,10 @@ static void MaybeCancelLastSeparator(State *state) {
 
 // Returns true if the identifier of the given length pointed to by
 // "mangled_cur" is anonymous namespace.
-static bool IdentifierIsAnonymousNamespace(State *state, int length) {
+static bool IdentifierIsAnonymousNamespace(State *state, size_t length) {
   // Returns true if "anon_prefix" is a proper prefix of "mangled_cur".
   static const char anon_prefix[] = "_GLOBAL__N_";
-  return (length > static_cast<int>(sizeof(anon_prefix) - 1) &&
+  return (length > (sizeof(anon_prefix) - 1) &&
           StrPrefix(RemainingInput(state), anon_prefix));
 }
 
@@ -542,7 +542,7 @@ static bool ParseUnnamedTypeName(State *state);
 static bool ParseNumber(State *state, int *number_out);
 static bool ParseFloatNumber(State *state);
 static bool ParseSeqId(State *state);
-static bool ParseIdentifier(State *state, int length);
+static bool ParseIdentifier(State *state, size_t length);
 static bool ParseOperatorName(State *state, int *arity);
 static bool ParseSpecialName(State *state);
 static bool ParseCallOffset(State *state);
@@ -786,7 +786,8 @@ static bool ParseSourceName(State *state) {
   if (guard.IsTooComplex()) return false;
   ParseState copy = state->parse_state;
   int length = -1;
-  if (ParseNumber(state, &length) && ParseIdentifier(state, length)) {
+  if (ParseNumber(state, &length) &&
+      ParseIdentifier(state, static_cast<size_t>(length))) {
     return true;
   }
   state->parse_state = copy;
@@ -864,7 +865,7 @@ static bool ParseNumber(State *state, int *number_out) {
   uint64_t number = 0;
   for (; *p != '\0'; ++p) {
     if (IsDigit(*p)) {
-      number = number * 10 + (*p - '0');
+      number = number * 10 + static_cast<uint64_t>(*p - '0');
     } else {
       break;
     }
@@ -879,7 +880,7 @@ static bool ParseNumber(State *state, int *number_out) {
     state->parse_state.mangled_idx += p - RemainingInput(state);
     if (number_out != nullptr) {
       // Note: possibly truncate "number".
-      *number_out = number;
+      *number_out = static_cast<int>(number);
     }
     return true;
   }
@@ -923,10 +924,10 @@ static bool ParseSeqId(State *state) {
 }
 
 // <identifier> ::= <unqualified source code identifier> (of given length)
-static bool ParseIdentifier(State *state, int length) {
+static bool ParseIdentifier(State *state, size_t length) {
   ComplexityGuard guard(state);
   if (guard.IsTooComplex()) return false;
-  if (length < 0 || !AtLeastNumCharsRemaining(RemainingInput(state), length)) {
+  if (!AtLeastNumCharsRemaining(RemainingInput(state), length)) {
     return false;
   }
   if (IdentifierIsAnonymousNamespace(state, length)) {

absl/debugging/internal/examine_stack.cc

@@ -278,13 +278,14 @@ void DumpStackTrace(int min_dropped_frames, int max_num_frames,
   void* stack_buf[kDefaultDumpStackFramesLimit];
   void** stack = stack_buf;
   int num_stack = kDefaultDumpStackFramesLimit;
-  int allocated_bytes = 0;
+  size_t allocated_bytes = 0;
 
   if (num_stack >= max_num_frames) {
     // User requested fewer frames than we already have space for.
     num_stack = max_num_frames;
   } else {
-    const size_t needed_bytes = max_num_frames * sizeof(stack[0]);
+    const size_t needed_bytes =
+        static_cast<size_t>(max_num_frames) * sizeof(stack[0]);
     void* p = Allocate(needed_bytes);
     if (p != nullptr) {  // We got the space.
       num_stack = max_num_frames;
@@ -293,12 +294,13 @@ void DumpStackTrace(int min_dropped_frames, int max_num_frames,
     }
   }
 
-  size_t depth = absl::GetStackTrace(stack, num_stack, min_dropped_frames + 1);
-  for (size_t i = 0; i < depth; i++) {
+  int depth = absl::GetStackTrace(stack, num_stack, min_dropped_frames + 1);
+  for (int i = 0; i < depth; i++) {
     if (symbolize_stacktrace) {
-      DumpPCAndSymbol(writer, writer_arg, stack[i], "    ");
+      DumpPCAndSymbol(writer, writer_arg, stack[static_cast<size_t>(i)],
+                      "    ");
     } else {
-      DumpPC(writer, writer_arg, stack[i], "    ");
+      DumpPC(writer, writer_arg, stack[static_cast<size_t>(i)], "    ");
     }
   }
 

absl/hash/internal/city.cc

@@ -97,7 +97,7 @@ static uint32_t Hash32Len13to24(const char *s, size_t len) {
   uint32_t d = Fetch32(s + (len >> 1));
   uint32_t e = Fetch32(s);
   uint32_t f = Fetch32(s + len - 4);
-  uint32_t h = len;
+  uint32_t h = static_cast<uint32_t>(len);
 
   return fmix(Mur(f, Mur(e, Mur(d, Mur(c, Mur(b, Mur(a, h)))))));
 }
@@ -106,15 +106,15 @@ static uint32_t Hash32Len0to4(const char *s, size_t len) {
   uint32_t b = 0;
   uint32_t c = 9;
   for (size_t i = 0; i < len; i++) {
-    signed char v = s[i];
-    b = b * c1 + v;
+    signed char v = static_cast<signed char>(s[i]);
+    b = b * c1 + static_cast<uint32_t>(v);
     c ^= b;
   }
-  return fmix(Mur(b, Mur(len, c)));
+  return fmix(Mur(b, Mur(static_cast<uint32_t>(len), c)));
 }
 
 static uint32_t Hash32Len5to12(const char *s, size_t len) {
-  uint32_t a = len, b = len * 5, c = 9, d = b;
+  uint32_t a = static_cast<uint32_t>(len), b = a * 5, c = 9, d = b;
   a += Fetch32(s);
   b += Fetch32(s + len - 4);
   c += Fetch32(s + ((len >> 1) & 4));
@@ -129,7 +129,7 @@ uint32_t CityHash32(const char *s, size_t len) {
   }
 
   // len > 24
-  uint32_t h = len, g = c1 * len, f = g;
+  uint32_t h = static_cast<uint32_t>(len), g = c1 * h, f = g;
 
   uint32_t a0 = Rotate32(Fetch32(s + len - 4) * c1, 17) * c2;
   uint32_t a1 = Rotate32(Fetch32(s + len - 8) * c1, 17) * c2;
@@ -230,11 +230,11 @@ static uint64_t HashLen0to16(const char *s, size_t len) {
     return HashLen16(len + (a << 3), Fetch32(s + len - 4), mul);
   }
   if (len > 0) {
-    uint8_t a = s[0];
-    uint8_t b = s[len >> 1];
-    uint8_t c = s[len - 1];
+    uint8_t a = static_cast<uint8_t>(s[0]);
+    uint8_t b = static_cast<uint8_t>(s[len >> 1]);
+    uint8_t c = static_cast<uint8_t>(s[len - 1]);
     uint32_t y = static_cast<uint32_t>(a) + (static_cast<uint32_t>(b) << 8);
-    uint32_t z = len + (static_cast<uint32_t>(c) << 2);
+    uint32_t z = static_cast<uint32_t>(len) + (static_cast<uint32_t>(c) << 2);
     return ShiftMix(y * k2 ^ z * k0) * k2;
   }
   return k2;

absl/hash/internal/low_level_hash.cc

@@ -106,7 +106,8 @@ uint64_t LowLevelHash(const void* data, size_t len, uint64_t seed,
   } else if (len > 0) {
     // If we have at least 1 and at most 3 bytes, read all of the provided
     // bits into A, with some adjustments.
-    a = ((ptr[0] << 16) | (ptr[len >> 1] << 8) | ptr[len - 1]);
+    a = static_cast<uint64_t>((ptr[0] << 16) | (ptr[len >> 1] << 8) |
+                              ptr[len - 1]);
     b = 0;
   } else {
     a = 0;