Correct various illegal type puns

Using reinterpret_cast for type punning (not allowed by the C++ standard) is not supported by GCC which notoriously miscompiles such code at -O2. Bug: 819294 Change-Id: I19a3e20a966ff590b9f3beb40984b6fc4fcc10db Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4328253 Auto-Submit: Bruno Pitrus <brunopitrus@hotmail.com> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org> Commit-Queue: Kinuko Yasuda <kinuko@chromium.org> Cr-Commit-Position: refs/heads/main@{#1119713}
chromium · Mar 21, 2023 · ad4d52b · ad4d52b
1 parent e0f76ca
commit ad4d52b
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Showing 3 changed files with 14 additions and 5 deletions.
diff --git a/third_party/blink/renderer/modules/xr/xr_cube_map.cc b/third_party/blink/renderer/modules/xr/xr_cube_map.cc
@@ -4,6 +4,8 @@
 
 #include "third_party/blink/renderer/modules/xr/xr_cube_map.h"
 
+#include <cstring>
+
 #include "base/cxx17_backports.h"
 #include "device/vr/public/mojom/vr_service.mojom-blink.h"
 #include "third_party/blink/renderer/modules/webgl/webgl_rendering_context_base.h"
@@ -19,7 +21,8 @@ bool IsPowerOfTwo(uint32_t value) {
 // This is an inversion of FloatToHalfFloat in ui/gfx/half_float.cc
 float HalfFloatToFloat(const uint16_t input) {
   uint32_t tmp = (input & 0x7fff) << 13 | (input & 0x8000) << 16;
-  float tmp2 = *reinterpret_cast<float*>(&tmp);
+  float tmp2;
+  std::memcpy(&tmp2, &tmp, 4);
   return tmp2 / 1.9259299444e-34f;
 }
 

diff --git a/third_party/blink/renderer/platform/audio/cpu/x86/vector_math_impl.h b/third_party/blink/renderer/platform/audio/cpu/x86/vector_math_impl.h
@@ -13,6 +13,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <cstring>
 
 #include "base/check_op.h"
 #include "third_party/blink/renderer/platform/audio/audio_array.h"
@@ -208,13 +209,14 @@ void Vclip(const float* source_p,
 // source_max = max(abs(source[k])) for all k
 void Vmaxmgv(const float* source_p, float* max_p, uint32_t frames_to_process) {
   constexpr uint32_t kMask = 0x7FFFFFFFu;
-
+  float kMask_float;
+  std::memcpy(&kMask_float, &kMask, 4);
   const float* const source_end_p = source_p + frames_to_process;
 
   DCHECK(IsAligned(source_p));
   DCHECK_EQ(0u, frames_to_process % kPackedFloatsPerRegister);
 
-  MType m_mask = MM_PS(set1)(*reinterpret_cast<const float*>(&kMask));
+  MType m_mask = MM_PS(set1)(kMask_float);
   MType m_max = MM_PS(setzero)();
 
   while (source_p < source_end_p) {

diff --git a/third_party/blink/renderer/platform/graphics/gpu/webgl_image_conversion.cc b/third_party/blink/renderer/platform/graphics/gpu/webgl_image_conversion.cc
@@ -4,6 +4,7 @@
 
 #include "third_party/blink/renderer/platform/graphics/gpu/webgl_image_conversion.h"
 
+#include <cstring>
 #include <limits>
 #include <memory>
 
@@ -416,7 +417,8 @@ const unsigned char g_shift_table[512] = {
     24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 13};
 
 uint16_t ConvertFloatToHalfFloat(float f) {
-  unsigned temp = *(reinterpret_cast<unsigned*>(&f));
+  unsigned temp;
+  std::memcpy(&temp, &f, 4);
   uint16_t signexp = (temp >> 23) & 0x1ff;
   return g_base_table[signexp] +
          ((temp & 0x007fffff) >> g_shift_table[signexp]);
@@ -834,7 +836,9 @@ float ConvertHalfFloatToFloat(uint16_t half) {
   uint32_t temp =
       g_mantissa_table[g_offset_table[half >> 10] + (half & 0x3ff)] +
       g_exponent_table[half >> 10];
-  return *(reinterpret_cast<float*>(&temp));
+  float ret;
+  std::memcpy(&ret, &temp, 4);
+  return ret;
 }
 
 /* BEGIN CODE SHARED WITH MOZILLA FIREFOX */