[llvm][TypeSize] Fix addition/subtraction in TypeSize. (#72979)

It seems TypeSize is currently broken in the sense that:

  TypeSize::Fixed(4) + TypeSize::Scalable(4) => TypeSize::Fixed(8)

without failing its assert that explicitly tests for this case:

  assert(LHS.Scalable == RHS.Scalable && ...);

The reason this fails is that `Scalable` is a static method of class
TypeSize,
and LHS and RHS are both objects of class TypeSize. So this is
evaluating
if the pointer to the function Scalable == the pointer to the function
Scalable,
which is always true because LHS and RHS have the same class.

This patch fixes the issue by renaming `TypeSize::Scalable` ->
`TypeSize::getScalable`, as well as `TypeSize::Fixed` to
`TypeSize::getFixed`,
so that it no longer clashes with the variable in
FixedOrScalableQuantity.

The new methods now also better match the coding standard, which
specifies that:
* Variable names should be nouns (as they represent state)
* Function names should be verb phrases (as they represent actions)

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/StackProtector.cpp b/llvm/lib/CodeGen/StackProtector.cpp
index 9a4d7ff..48dc7cb 100644
--- a/llvm/lib/CodeGen/StackProtector.cpp
+++ b/llvm/lib/CodeGen/StackProtector.cpp
@@ -215,14 +215,14 @@ static bool HasAddressTaken(const Instruction *AI, TypeSize AllocSize,
       APInt Offset(IndexSize, 0);
       if (!GEP->accumulateConstantOffset(DL, Offset))
         return true;
-      TypeSize OffsetSize = TypeSize::Fixed(Offset.getLimitedValue());
+      TypeSize OffsetSize = TypeSize::getFixed(Offset.getLimitedValue());
       if (!TypeSize::isKnownGT(AllocSize, OffsetSize))
         return true;
       // Adjust AllocSize to be the space remaining after this offset.
       // We can't subtract a fixed size from a scalable one, so in that case
       // assume the scalable value is of minimum size.
       TypeSize NewAllocSize =
-          TypeSize::Fixed(AllocSize.getKnownMinValue()) - OffsetSize;
+          TypeSize::getFixed(AllocSize.getKnownMinValue()) - OffsetSize;
       if (HasAddressTaken(I, NewAllocSize, M, VisitedPHIs))
         return true;
       break;