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Fixed strict-aliasing warnings

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Minor update to the implementation of a few internal tagging
methods in Vtr to avoid violating strict-aliasing rules.
Specifically, switched to using std::memcpy instead of
reinterpret_cast to implement type punning.
This commit is contained in:
David G Yu 2020-02-28 16:28:33 -08:00
parent 6339ac5c43
commit 6dde62d48f
3 changed files with 30 additions and 11 deletions
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9
opensubdiv/vtr/fvarLevel.cpp
View File

@ -1050,20 +1050,17 @@ FVarLevel::getFaceCompositeValueTag(Index faceIndex) const {
typedef ValueTag::ValueTagSize ValueTagSize;
ValueTag compTag;
ValueTagSize & compInt = *(reinterpret_cast<ValueTagSize *>(&compTag));
compInt = 0;
ValueTagSize compInt = 0;
for (int i = 0; i < faceValues.size(); ++i) {
Index srcValueIndex = findVertexValueIndex(faceVerts[i], faceValues[i]);
assert(_vertValueIndices[srcValueIndex] == faceValues[i]);
ValueTag const & srcTag = _vertValueTags[srcValueIndex];
ValueTagSize const & srcInt = *(reinterpret_cast<ValueTagSize const *>(&srcTag));
ValueTagSize const srcInt = srcTag.getBits();
compInt |= srcInt;
}
return compTag;
return ValueTag(compInt);
}
} // end namespace internal

10
opensubdiv/vtr/fvarLevel.h
View File

@ -135,6 +135,16 @@ public:
ValueTagSize _infIrregular : 1; // value span includes inf-sharp irregularity
Level::VTag combineWithLevelVTag(Level::VTag) const;
// Alternate constructor and accessor for dealing with integer bits directly:
explicit ValueTag(ValueTagSize bits) {
std::memcpy(this, &bits, sizeof(bits));
}
ValueTagSize getBits() const {
ValueTagSize bits;
std::memcpy(&bits, this, sizeof(bits));
return bits;
}
};
typedef Vtr::ConstArray<ValueTag> ConstValueTagArray;

20
opensubdiv/vtr/level.h
View File

@ -126,8 +126,14 @@ public:
VTagSize _infIrregular : 1; // fixed
// Alternate constructor and accessor for dealing with integer bits directly:
explicit VTag(VTagSize bits) { *this = *reinterpret_cast<VTag const *>(&bits); }
VTagSize getBits() const { return *reinterpret_cast<VTagSize const *>(this); }
explicit VTag(VTagSize bits) {
std::memcpy(this, &bits, sizeof(bits));
}
VTagSize getBits() const {
VTagSize bits;
std::memcpy(&bits, this, sizeof(bits));
return bits;
}
static VTag BitwiseOr(VTag const vTags[], int size = 4);
};
@ -145,8 +151,14 @@ public:
ETagSize _semiSharp : 1; // variable
// Alternate constructor and accessor for dealing with integer bits directly:
explicit ETag(ETagSize bits) { *this = *reinterpret_cast<ETag const *>(&bits); }
ETagSize getBits() const { return *reinterpret_cast<ETagSize const *>(this); }
explicit ETag(ETagSize bits) {
std::memcpy(this, &bits, sizeof(bits));
}
ETagSize getBits() const {
ETagSize bits;
std::memcpy(&bits, this, sizeof(bits));
return bits;
}
static ETag BitwiseOr(ETag const eTags[], int size = 4);
};