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SIL: let SingleValueInstruction only inherit from a single SILNode.

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This removes the ambiguity when casting from a SingleValueInstruction to SILNode, which makes the code simpler. E.g. the "isRepresentativeSILNode" logic is not needed anymore.
Also, it reduces the size of the most used instruction class - SingleValueInstruction - by one pointer.

Conceptually, SILInstruction is still a SILNode. But implementation-wise SILNode is not a base class of SILInstruction anymore.
Only the two sub-classes of SILInstruction - SingleValueInstruction and NonSingleValueInstruction - inherit from SILNode. SingleValueInstruction's SILNode is embedded into a ValueBase and its relative offset in the class is the same as in NonSingleValueInstruction (see SILNodeOffsetChecker).
This makes it possible to cast from a SILInstruction to a SILNode without knowing which SILInstruction sub-class it is.
Casting to SILNode cannot be done implicitly, but only with an LLVM `cast` or with SILInstruction::asSILNode(). But this is a rare case anyway.
This commit is contained in:
Erik Eckstein
2021-01-20 11:09:50 +01:00
parent da197240c1
commit 011358edd6
31 changed files with 474 additions and 501 deletions
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17
lib/SIL/IR/SILValue.cpp
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@@ -121,23 +121,6 @@ SILModule *SILNode::getModule() const {
return nullptr;
}
const SILNode *SILNode::getRepresentativeSILNodeSlowPath() const {
assert(getStorageLoc() != SILNodeStorageLocation::Instruction);
if (isa<SingleValueInstruction>(this)) {
assert(hasMultipleSILNodeBases(getKind()));
return &static_cast<const SILInstruction &>(
static_cast<const SingleValueInstruction &>(
static_cast<const ValueBase &>(*this)));
}
if (auto *MVR = dyn_cast<MultipleValueInstructionResult>(this)) {
return MVR->getParent();
}
llvm_unreachable("Invalid value for slow path");
}
/// Get a location for this value.
SILLocation SILValue::getLoc() const {
if (auto *instr = Value->getDefiningInstruction())