Fix "unsafe narrowing" warnings in absl, 1/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 .h and win32 .inc files.)

Bug: chromium:1292951
PiperOrigin-RevId: 463835431
Change-Id: If8e5f7f651d5cd96035e23e4623bdb08a7fedabe

absl/base/internal/spinlock.cc

@@ -178,7 +178,7 @@ void SpinLock::SlowUnlock(uint32_t lock_value) {
   // reserve a unitary wait time to represent that a waiter exists without our
   // own acquisition having been contended.
   if ((lock_value & kWaitTimeMask) != kSpinLockSleeper) {
-    const uint64_t wait_cycles = DecodeWaitCycles(lock_value);
+    const int64_t wait_cycles = DecodeWaitCycles(lock_value);
     ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
     submit_profile_data(this, wait_cycles);
     ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
@@ -220,9 +220,9 @@ uint32_t SpinLock::EncodeWaitCycles(int64_t wait_start_time,
   return clamped;
 }
 
-uint64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) {
+int64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) {
   // Cast to uint32_t first to ensure bits [63:32] are cleared.
-  const uint64_t scaled_wait_time =
+  const int64_t scaled_wait_time =
       static_cast<uint32_t>(lock_value & kWaitTimeMask);
   return scaled_wait_time << (kProfileTimestampShift - kLockwordReservedShift);
 }

absl/base/internal/spinlock.h

@@ -137,7 +137,7 @@ class ABSL_LOCKABLE SpinLock {
                                    int64_t wait_end_time);
 
   // Extract number of wait cycles in a lock value.
-  static uint64_t DecodeWaitCycles(uint32_t lock_value);
+  static int64_t DecodeWaitCycles(uint32_t lock_value);
 
   // Provide access to protected method above.  Use for testing only.
   friend struct SpinLockTest;

absl/base/internal/spinlock_win32.inc

@@ -27,7 +27,10 @@ void ABSL_INTERNAL_C_SYMBOL(AbslInternalSpinLockDelay)(
   } else if (loop == 1) {
     Sleep(0);
   } else {
-    Sleep(absl::base_internal::SpinLockSuggestedDelayNS(loop) / 1000000);
+    // SpinLockSuggestedDelayNS() always returns a positive integer, so this
+    // static_cast is safe.
+    Sleep(static_cast<DWORD>(
+        absl::base_internal::SpinLockSuggestedDelayNS(loop) / 1000000));
   }
 }
 

absl/base/internal/unscaledcycleclock.h

@@ -119,7 +119,7 @@ class UnscaledCycleClock {
 inline int64_t UnscaledCycleClock::Now() {
   uint64_t low, high;
   __asm__ volatile("rdtsc" : "=a"(low), "=d"(high));
-  return (high << 32) | low;
+  return static_cast<int64_t>((high << 32) | low);
 }
 
 #endif

absl/base/spinlock_test_common.cc

@@ -48,7 +48,7 @@ struct SpinLockTest {
                                    int64_t wait_end_time) {
     return SpinLock::EncodeWaitCycles(wait_start_time, wait_end_time);
   }
-  static uint64_t DecodeWaitCycles(uint32_t lock_value) {
+  static int64_t DecodeWaitCycles(uint32_t lock_value) {
     return SpinLock::DecodeWaitCycles(lock_value);
   }
 };
@@ -133,20 +133,20 @@ TEST(SpinLock, WaitCyclesEncoding) {
   // but the lower kProfileTimestampShift will be dropped.
   const int kMaxCyclesShift =
     32 - kLockwordReservedShift + kProfileTimestampShift;
-  const uint64_t kMaxCycles = (int64_t{1} << kMaxCyclesShift) - 1;
+  const int64_t kMaxCycles = (int64_t{1} << kMaxCyclesShift) - 1;
 
   // These bits should be zero after encoding.
   const uint32_t kLockwordReservedMask = (1 << kLockwordReservedShift) - 1;
 
   // These bits are dropped when wait cycles are encoded.
-  const uint64_t kProfileTimestampMask = (1 << kProfileTimestampShift) - 1;
+  const int64_t kProfileTimestampMask = (1 << kProfileTimestampShift) - 1;
 
   // Test a bunch of random values
   std::default_random_engine generator;
   // Shift to avoid overflow below.
-  std::uniform_int_distribution<uint64_t> time_distribution(
-      0, std::numeric_limits<uint64_t>::max() >> 4);
-  std::uniform_int_distribution<uint64_t> cycle_distribution(0, kMaxCycles);
+  std::uniform_int_distribution<int64_t> time_distribution(
+      0, std::numeric_limits<int64_t>::max() >> 3);
+  std::uniform_int_distribution<int64_t> cycle_distribution(0, kMaxCycles);
 
   for (int i = 0; i < 100; i++) {
     int64_t start_time = time_distribution(generator);
@@ -154,7 +154,7 @@ TEST(SpinLock, WaitCyclesEncoding) {
     int64_t end_time = start_time + cycles;
     uint32_t lock_value = SpinLockTest::EncodeWaitCycles(start_time, end_time);
     EXPECT_EQ(0, lock_value & kLockwordReservedMask);
-    uint64_t decoded = SpinLockTest::DecodeWaitCycles(lock_value);
+    int64_t decoded = SpinLockTest::DecodeWaitCycles(lock_value);
     EXPECT_EQ(0, decoded & kProfileTimestampMask);
     EXPECT_EQ(cycles & ~kProfileTimestampMask, decoded);
   }
@@ -178,21 +178,21 @@ TEST(SpinLock, WaitCyclesEncoding) {
   // Test clamping
   uint32_t max_value =
     SpinLockTest::EncodeWaitCycles(start_time, start_time + kMaxCycles);
-  uint64_t max_value_decoded = SpinLockTest::DecodeWaitCycles(max_value);
-  uint64_t expected_max_value_decoded = kMaxCycles & ~kProfileTimestampMask;
+  int64_t max_value_decoded = SpinLockTest::DecodeWaitCycles(max_value);
+  int64_t expected_max_value_decoded = kMaxCycles & ~kProfileTimestampMask;
   EXPECT_EQ(expected_max_value_decoded, max_value_decoded);
 
   const int64_t step = (1 << kProfileTimestampShift);
   uint32_t after_max_value =
     SpinLockTest::EncodeWaitCycles(start_time, start_time + kMaxCycles + step);
-  uint64_t after_max_value_decoded =
+  int64_t after_max_value_decoded =
       SpinLockTest::DecodeWaitCycles(after_max_value);
   EXPECT_EQ(expected_max_value_decoded, after_max_value_decoded);
 
   uint32_t before_max_value = SpinLockTest::EncodeWaitCycles(
       start_time, start_time + kMaxCycles - step);
-  uint64_t before_max_value_decoded =
-    SpinLockTest::DecodeWaitCycles(before_max_value);
+  int64_t before_max_value_decoded =
+      SpinLockTest::DecodeWaitCycles(before_max_value);
   EXPECT_GT(expected_max_value_decoded, before_max_value_decoded);
 }
 

absl/container/internal/hashtablez_sampler.cc

@@ -215,21 +215,20 @@ void SetHashtablezSampleParameterInternal(int32_t rate) {
   }
 }
 
-int32_t GetHashtablezMaxSamples() {
+size_t GetHashtablezMaxSamples() {
   return GlobalHashtablezSampler().GetMaxSamples();
 }
 
-void SetHashtablezMaxSamples(int32_t max) {
+void SetHashtablezMaxSamples(size_t max) {
   SetHashtablezMaxSamplesInternal(max);
   TriggerHashtablezConfigListener();
 }
 
-void SetHashtablezMaxSamplesInternal(int32_t max) {
+void SetHashtablezMaxSamplesInternal(size_t max) {
   if (max > 0) {
     GlobalHashtablezSampler().SetMaxSamples(max);
   } else {
-    ABSL_RAW_LOG(ERROR, "Invalid hashtablez max samples: %lld",
-                 static_cast<long long>(max));  // NOLINT(runtime/int)
+    ABSL_RAW_LOG(ERROR, "Invalid hashtablez max samples: 0");
   }
 }
 

absl/container/internal/hashtablez_sampler.h

@@ -281,9 +281,9 @@ void SetHashtablezSampleParameter(int32_t rate);
 void SetHashtablezSampleParameterInternal(int32_t rate);
 
 // Sets a soft max for the number of samples that will be kept.
-int32_t GetHashtablezMaxSamples();
-void SetHashtablezMaxSamples(int32_t max);
-void SetHashtablezMaxSamplesInternal(int32_t max);
+size_t GetHashtablezMaxSamples();
+void SetHashtablezMaxSamples(size_t max);
+void SetHashtablezMaxSamplesInternal(size_t max);
 
 // Configuration override.
 // This allows process-wide sampling without depending on order of

absl/container/internal/inlined_vector.h

@@ -784,9 +784,9 @@ auto Storage<T, N, A>::Erase(ConstIterator<A> from, ConstIterator<A> to)
     -> Iterator<A> {
   StorageView<A> storage_view = MakeStorageView();
 
-  SizeType<A> erase_size = std::distance(from, to);
-  SizeType<A> erase_index =
-      std::distance(ConstIterator<A>(storage_view.data), from);
+  auto erase_size = static_cast<SizeType<A>>(std::distance(from, to));
+  auto erase_index = static_cast<SizeType<A>>(
+      std::distance(ConstIterator<A>(storage_view.data), from));
   SizeType<A> erase_end_index = erase_index + erase_size;
 
   IteratorValueAdapter<A, MoveIterator<A>> move_values(

absl/container/internal/raw_hash_set.h

@@ -545,7 +545,7 @@ struct GroupSse2Impl {
 
   // Returns a bitmask representing the positions of slots that match hash.
   BitMask<uint32_t, kWidth> Match(h2_t hash) const {
-    auto match = _mm_set1_epi8(hash);
+    auto match = _mm_set1_epi8(static_cast<char>(hash));
     return BitMask<uint32_t, kWidth>(
         static_cast<uint32_t>(_mm_movemask_epi8(_mm_cmpeq_epi8(match, ctrl))));
   }
@@ -557,7 +557,7 @@ struct GroupSse2Impl {
     return NonIterableBitMask<uint32_t, kWidth>(
         static_cast<uint32_t>(_mm_movemask_epi8(_mm_sign_epi8(ctrl, ctrl))));
 #else
-    auto match = _mm_set1_epi8(static_cast<h2_t>(ctrl_t::kEmpty));
+    auto match = _mm_set1_epi8(static_cast<char>(ctrl_t::kEmpty));
     return NonIterableBitMask<uint32_t, kWidth>(
         static_cast<uint32_t>(_mm_movemask_epi8(_mm_cmpeq_epi8(match, ctrl))));
 #endif
@@ -565,14 +565,14 @@ struct GroupSse2Impl {
 
   // Returns a bitmask representing the positions of empty or deleted slots.
   NonIterableBitMask<uint32_t, kWidth> MaskEmptyOrDeleted() const {
-    auto special = _mm_set1_epi8(static_cast<uint8_t>(ctrl_t::kSentinel));
+    auto special = _mm_set1_epi8(static_cast<char>(ctrl_t::kSentinel));
     return NonIterableBitMask<uint32_t, kWidth>(static_cast<uint32_t>(
         _mm_movemask_epi8(_mm_cmpgt_epi8_fixed(special, ctrl))));
   }
 
   // Returns the number of trailing empty or deleted elements in the group.
   uint32_t CountLeadingEmptyOrDeleted() const {
-    auto special = _mm_set1_epi8(static_cast<uint8_t>(ctrl_t::kSentinel));
+    auto special = _mm_set1_epi8(static_cast<char>(ctrl_t::kSentinel));
     return TrailingZeros(static_cast<uint32_t>(
         _mm_movemask_epi8(_mm_cmpgt_epi8_fixed(special, ctrl)) + 1));
   }
@@ -635,7 +635,8 @@ struct GroupAArch64Impl {
     // Clang and GCC optimize countr_zero to rbit+clz without any check for 0,
     // so we should be fine.
     constexpr uint64_t bits = 0x0101010101010101ULL;
-    return countr_zero((mask | ~(mask >> 7)) & bits) >> 3;
+    return static_cast<uint32_t>(countr_zero((mask | ~(mask >> 7)) & bits) >>
+                                 3);
   }
 
   void ConvertSpecialToEmptyAndFullToDeleted(ctrl_t* dst) const {

absl/debugging/internal/stacktrace_win32-inl.inc

@@ -63,11 +63,12 @@ static RtlCaptureStackBackTrace_Function* const RtlCaptureStackBackTrace_fn =
 template <bool IS_STACK_FRAMES, bool IS_WITH_CONTEXT>
 static int UnwindImpl(void** result, int* sizes, int max_depth, int skip_count,
                       const void*, int* min_dropped_frames) {
-  int n = 0;
-  if (!RtlCaptureStackBackTrace_fn) {
-    // can't find a stacktrace with no function to call
+  USHORT n = 0;
+  if (!RtlCaptureStackBackTrace_fn || skip_count < 0 || max_depth < 0) {
+    // can't get a stacktrace with no function/invalid args
   } else {
-    n = (int)RtlCaptureStackBackTrace_fn(skip_count + 2, max_depth, result, 0);
+    n = RtlCaptureStackBackTrace_fn(static_cast<ULONG>(skip_count) + 2,
+                                    static_cast<ULONG>(max_depth), result, 0);
   }
   if (IS_STACK_FRAMES) {
     // No implementation for finding out the stack frame sizes yet.

absl/debugging/symbolize_win32.inc

@@ -65,14 +65,15 @@ bool Symbolize(const void* pc, char* out, int out_size) {
   if (!SymFromAddr(process, reinterpret_cast<DWORD64>(pc), nullptr, symbol)) {
     return false;
   }
-  strncpy(out, symbol->Name, out_size);
-  if (out[out_size - 1] != '\0') {
+  const size_t out_size_t = static_cast<size_t>(out_size);
+  strncpy(out, symbol->Name, out_size_t);
+  if (out[out_size_t - 1] != '\0') {
     // strncpy() does not '\0' terminate when it truncates.
     static constexpr char kEllipsis[] = "...";
-    int ellipsis_size =
-        std::min<int>(sizeof(kEllipsis) - 1, out_size - 1);
-    memcpy(out + out_size - ellipsis_size - 1, kEllipsis, ellipsis_size);
-    out[out_size - 1] = '\0';
+    size_t ellipsis_size =
+        std::min(sizeof(kEllipsis) - 1, out_size_t - 1);
+    memcpy(out + out_size_t - ellipsis_size - 1, kEllipsis, ellipsis_size);
+    out[out_size_t - 1] = '\0';
   }
   return true;
 }

absl/profiling/internal/sample_recorder.h

@@ -77,8 +77,8 @@ class SampleRecorder {
   // samples that have been dropped.
   int64_t Iterate(const std::function<void(const T& stack)>& f);
 
-  int32_t GetMaxSamples() const;
-  void SetMaxSamples(int32_t max);
+  size_t GetMaxSamples() const;
+  void SetMaxSamples(size_t max);
 
  private:
   void PushNew(T* sample);
@@ -88,7 +88,7 @@ class SampleRecorder {
 
   std::atomic<size_t> dropped_samples_;
   std::atomic<size_t> size_estimate_;
-  std::atomic<int32_t> max_samples_{1 << 20};
+  std::atomic<size_t> max_samples_{1 << 20};
 
   // Intrusive lock free linked lists for tracking samples.
   //
@@ -186,7 +186,7 @@ T* SampleRecorder<T>::PopDead(Targs... args) {
 template <typename T>
 template <typename... Targs>
 T* SampleRecorder<T>::Register(Targs&&... args) {
-  int64_t size = size_estimate_.fetch_add(1, std::memory_order_relaxed);
+  size_t size = size_estimate_.fetch_add(1, std::memory_order_relaxed);
   if (size > max_samples_.load(std::memory_order_relaxed)) {
     size_estimate_.fetch_sub(1, std::memory_order_relaxed);
     dropped_samples_.fetch_add(1, std::memory_order_relaxed);
@@ -229,12 +229,12 @@ int64_t SampleRecorder<T>::Iterate(
 }
 
 template <typename T>
-void SampleRecorder<T>::SetMaxSamples(int32_t max) {
+void SampleRecorder<T>::SetMaxSamples(size_t max) {
   max_samples_.store(max, std::memory_order_release);
 }
 
 template <typename T>
-int32_t SampleRecorder<T>::GetMaxSamples() const {
+size_t SampleRecorder<T>::GetMaxSamples() const {
   return max_samples_.load(std::memory_order_acquire);
 }
 

absl/strings/cord_buffer.h

@@ -330,8 +330,7 @@ class CordBuffer {
 
     // Returns the available area of the internal SSO data
     absl::Span<char> short_available() {
-      assert(is_short());
-      const size_t length = (short_rep.raw_size >> 1);
+      const size_t length = short_length();
       return absl::Span<char>(short_rep.data + length,
                               kInlineCapacity - length);
     }
@@ -347,7 +346,7 @@ class CordBuffer {
     // Returns the length of the internal SSO data.
     size_t short_length() const {
       assert(is_short());
-      return short_rep.raw_size >> 1;
+      return static_cast<size_t>(short_rep.raw_size >> 1);
     }
 
     // Sets the length of the internal SSO data.

absl/strings/internal/char_map.h

@@ -103,10 +103,9 @@ class Charmap {
   constexpr Charmap(uint64_t b0, uint64_t b1, uint64_t b2, uint64_t b3)
       : m_{b0, b1, b2, b3} {}
 
-  static constexpr uint64_t RangeForWord(unsigned char lo, unsigned char hi,
-                                         uint64_t word) {
-    return OpenRangeFromZeroForWord(hi + 1, word) &
-           ~OpenRangeFromZeroForWord(lo, word);
+  static constexpr uint64_t RangeForWord(char lo, char hi, uint64_t word) {
+    return OpenRangeFromZeroForWord(static_cast<unsigned char>(hi) + 1, word) &
+           ~OpenRangeFromZeroForWord(static_cast<unsigned char>(lo), word);
   }
 
   // All the chars in the specified word of the range [0, upper).
@@ -119,13 +118,16 @@ class Charmap {
                      : (~static_cast<uint64_t>(0) >> (64 - upper % 64));
   }
 
-  static constexpr uint64_t CharMaskForWord(unsigned char x, uint64_t word) {
-    return (x / 64 == word) ? (static_cast<uint64_t>(1) << (x % 64)) : 0;
+  static constexpr uint64_t CharMaskForWord(char x, uint64_t word) {
+    const auto unsigned_x = static_cast<unsigned char>(x);
+    return (unsigned_x / 64 == word)
+               ? (static_cast<uint64_t>(1) << (unsigned_x % 64))
+               : 0;
   }
 
- private:
-  void SetChar(unsigned char c) {
-    m_[c / 64] |= static_cast<uint64_t>(1) << (c % 64);
+  void SetChar(char c) {
+    const auto unsigned_c = static_cast<unsigned char>(c);
+    m_[unsigned_c / 64] |= static_cast<uint64_t>(1) << (unsigned_c % 64);
   }
 
   uint64_t m_[4];

absl/strings/internal/cord_internal.h

@@ -570,7 +570,7 @@ class InlineData {
   // Requires the current instance to hold inline data.
   size_t inline_size() const {
     assert(!is_tree());
-    return tag() >> 1;
+    return static_cast<size_t>(tag()) >> 1;
   }
 
   // Sets the size of the inlined character data inside this instance.

absl/strings/internal/str_format/parser.h

@@ -155,10 +155,11 @@ bool ParseFormatString(string_view src, Consumer consumer) {
         static_cast<const char*>(memchr(p, '%', static_cast<size_t>(end - p)));
     if (!percent) {
       // We found the last substring.
-      return consumer.Append(string_view(p, end - p));
+      return consumer.Append(string_view(p, static_cast<size_t>(end - p)));
     }
     // We found a percent, so push the text run then process the percent.
-    if (ABSL_PREDICT_FALSE(!consumer.Append(string_view(p, percent - p)))) {
+    if (ABSL_PREDICT_FALSE(!consumer.Append(
+            string_view(p, static_cast<size_t>(percent - p))))) {
       return false;
     }
     if (ABSL_PREDICT_FALSE(percent + 1 >= end)) return false;
@@ -189,7 +190,8 @@ bool ParseFormatString(string_view src, Consumer consumer) {
       p = ConsumeUnboundConversion(percent + 1, end, &conv, &next_arg);
       if (ABSL_PREDICT_FALSE(p == nullptr)) return false;
       if (ABSL_PREDICT_FALSE(!consumer.ConvertOne(
-          conv, string_view(percent + 1, p - (percent + 1))))) {
+              conv, string_view(percent + 1,
+                                static_cast<size_t>(p - (percent + 1)))))) {
         return false;
       }
     } else {

absl/strings/substitute.h

@@ -125,28 +125,44 @@ class Arg {
   }
   Arg(short value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(unsigned short value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(int value)  // NOLINT(runtime/explicit)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(unsigned int value)  // NOLINT(runtime/explicit)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(long value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(unsigned long value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(long long value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(unsigned long long value)  // NOLINT(*)
       : piece_(scratch_,
-               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) {}
+               static_cast<size_t>(
+                   numbers_internal::FastIntToBuffer(value, scratch_) -
+                   scratch_)) {}
   Arg(float value)  // NOLINT(runtime/explicit)
       : piece_(scratch_, numbers_internal::SixDigitsToBuffer(value, scratch_)) {
   }

absl/synchronization/internal/kernel_timeout.h

@@ -111,7 +111,8 @@ class KernelTimeout {
       constexpr uint64_t max_nanos =
           (std::numeric_limits<int64_t>::max)() - 999999u;
       uint64_t ms_from_now =
-          (std::min<uint64_t>(max_nanos, ns_ - now) + 999999u) / 1000000u;
+          ((std::min)(max_nanos, static_cast<uint64_t>(ns_ - now)) + 999999u) /
+          1000000u;
       if (ms_from_now > kInfinite) {
         return kInfinite;
       }