From 84782b8ad3ccf520e17da4702af5b91904a03fbe Mon Sep 17 00:00:00 2001 From: Thomas Van Lenten Date: Thu, 19 Sep 2019 12:07:04 -0400 Subject: [PATCH] [ObjC] Don't use unions and instead use memcpy for the type swaps. The code in question hasn't change in a long time so the cause of https://github.com/firebase/firebase-ios-sdk/issues/3851 still appears to be an Xcode 11 clang change/bug; but this does appear to be slightly better code for the work being done. --- objectivec/GPBUtilities_PackagePrivate.h | 28 ++++++++++++++---------- 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/objectivec/GPBUtilities_PackagePrivate.h b/objectivec/GPBUtilities_PackagePrivate.h index ed424ce399b39..336a745ca1598 100644 --- a/objectivec/GPBUtilities_PackagePrivate.h +++ b/objectivec/GPBUtilities_PackagePrivate.h @@ -71,27 +71,31 @@ GPB_INLINE void GPBDebugCheckRuntimeVersion() { // Conversion functions for de/serializing floating point types. GPB_INLINE int64_t GPBConvertDoubleToInt64(double v) { - union { double f; int64_t i; } u; - u.f = v; - return u.i; + GPBInternalCompileAssert(sizeof(double) == sizeof(int64_t), double_not_64_bits); + int64_t result; + memcpy(&result, &v, sizeof(result)); + return result; } GPB_INLINE int32_t GPBConvertFloatToInt32(float v) { - union { float f; int32_t i; } u; - u.f = v; - return u.i; + GPBInternalCompileAssert(sizeof(float) == sizeof(int32_t), float_not_32_bits); + int32_t result; + memcpy(&result, &v, sizeof(result)); + return result; } GPB_INLINE double GPBConvertInt64ToDouble(int64_t v) { - union { double f; int64_t i; } u; - u.i = v; - return u.f; + GPBInternalCompileAssert(sizeof(double) == sizeof(int64_t), double_not_64_bits); + double result; + memcpy(&result, &v, sizeof(result)); + return result; } GPB_INLINE float GPBConvertInt32ToFloat(int32_t v) { - union { float f; int32_t i; } u; - u.i = v; - return u.f; + GPBInternalCompileAssert(sizeof(float) == sizeof(int32_t), float_not_32_bits); + float result; + memcpy(&result, &v, sizeof(result)); + return result; } GPB_INLINE int32_t GPBLogicalRightShift32(int32_t value, int32_t spaces) {