Reduce duplication in MCSymbol Name handling. NFC>

Based on feedback to r239428 by David Blaikie, use const_cast to reduce
duplication of the const and non-const versions of getNameEntryPtr.

Also have that method return the pointer to the name directly instead
of users having to then get the name from the union.

Finally, add a FIXME that we should use a static_assert once available in
the new operator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239429 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Pete Cooper 2015-06-09 20:41:08 +00:00
parent 5c8a22f11b
commit 38f72d04ea
2 changed files with 7 additions and 8 deletions

View File

@ -136,7 +136,7 @@ protected: // MCContext creates and uniques these.
Kind(Kind) {
Offset = 0;
if (Name)
getNameEntryPtr().NameEntry = Name;
getNameEntryPtr() = Name;
}
// Provide custom new/delete as we will only allocate space for a name
@ -169,15 +169,13 @@ private:
}
/// \brief Get a reference to the name field. Requires that we have a name
NameEntryStorageTy &getNameEntryPtr() {
const StringMapEntry<bool> *&getNameEntryPtr() {
assert(HasName && "Name is required");
NameEntryStorageTy *Name = reinterpret_cast<NameEntryStorageTy *>(this);
return *(Name - 1);
return (*(Name - 1)).NameEntry;
}
const NameEntryStorageTy &getNameEntryPtr() const {
assert(HasName && "Name is required");
const auto *Name = reinterpret_cast<const NameEntryStorageTy *>(this);
return *(Name - 1);
const StringMapEntry<bool> *&getNameEntryPtr() const {
return const_cast<MCSymbol*>(this)->getNameEntryPtr();
}
public:
@ -186,7 +184,7 @@ public:
if (!HasName)
return StringRef();
return getNameEntryPtr().NameEntry->first();
return getNameEntryPtr()->first();
}
bool isRegistered() const { return IsRegistered; }

View File

@ -28,6 +28,7 @@ void *MCSymbol::operator new(size_t s, const StringMapEntry<bool> *Name,
// For safety, ensure that the alignment of a pointer is enough for an
// MCSymbol. This also ensures we don't need padding between the name and
// symbol.
// FIXME: Use static_assert when constexpr is supported.
assert(alignOf<MCSymbol>() <= alignOf<NameEntryStorageTy>() &&
"Bad alignment of MCSymbol");
void *Storage = Ctx.allocate(Size, alignOf<NameEntryStorageTy>());