IR: Stop using DIDescriptor::is*() and auto-casting

`DIDescriptor`'s subclasses allow construction from incompatible
pointers, and `DIDescriptor` defines a series of `isa<>`-like functions
(e.g., `isCompileUnit()` instead of `isa<MDCompileUnit>()`) that clients
tend to use like this:

    if (DICompileUnit(N).isCompileUnit())
      foo(DICompileUnit(N));

These construction patterns work together to make `DIDescriptor` behave
differently from normal pointers.

Instead, use built-in `isa<>`, `dyn_cast<>`, etc., and only build
`DIDescriptor`s from pointers that are valid for their type.

I've split this into a few commits for different parts of LLVM and clang
(to decrease the patch size and increase the chance of review).
Generally the changes I made were NFC, but in a few places I made things
stricter if it made sense from the surrounded code.

Eventually a follow-up commit will remove the API for the "old" way.

llvm-svn: 234255

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/Linker/LinkModules.cpp b/llvm/lib/Linker/LinkModules.cpp
index 21edc504080..75849db4999 100644
--- a/llvm/lib/Linker/LinkModules.cpp
+++ b/llvm/lib/Linker/LinkModules.cpp
@@ -1269,14 +1269,14 @@ void ModuleLinker::stripReplacedSubprograms() {
   if (!CompileUnits)
     return;
   for (unsigned I = 0, E = CompileUnits->getNumOperands(); I != E; ++I) {
-    DICompileUnit CU(CompileUnits->getOperand(I));
+    DICompileUnit CU = cast<MDCompileUnit>(CompileUnits->getOperand(I));
     assert(CU && "Expected valid compile unit");
 
-    DITypedArray<DISubprogram> SPs(CU.getSubprograms());
+    MDSubprogramArray SPs(CU.getSubprograms());
     assert(SPs && "Expected valid subprogram array");
 
-    for (unsigned S = 0, SE = SPs.getNumElements(); S != SE; ++S) {
-      DISubprogram SP = SPs.getElement(S);
+    for (unsigned S = 0, SE = SPs.size(); S != SE; ++S) {
+      DISubprogram SP = SPs[S];
       if (!SP || !SP.getFunction() || !Functions.count(SP.getFunction()))
         continue;