[Alignment] Use llvm::Align in MachineFunction and TargetLowering - fixes mir parsing

Summary:
This catches malformed mir files which specify alignment as log2 instead of pow2.
See https://reviews.llvm.org/D65945 for reference,

This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: MatzeB, qcolombet, dschuff, arsenm, sdardis, nemanjai, jvesely, nhaehnle, hiraditya, kbarton, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67433

llvm-svn: 371608
diff --git a/llvm/lib/Target/Mips/MipsConstantIslandPass.cpp b/llvm/lib/Target/Mips/MipsConstantIslandPass.cpp
index 8907a72..4cd64c6 100644
--- a/llvm/lib/Target/Mips/MipsConstantIslandPass.cpp
+++ b/llvm/lib/Target/Mips/MipsConstantIslandPass.cpp
@@ -542,7 +542,7 @@
 
   // The function needs to be as aligned as the basic blocks. The linker may
   // move functions around based on their alignment.
-  MF->ensureLogAlignment(BB->getLogAlignment());
+  MF->ensureAlignment(BB->getAlignment());
 
   // Order the entries in BB by descending alignment.  That ensures correct
   // alignment of all entries as long as BB is sufficiently aligned.  Keep
@@ -1259,7 +1259,7 @@
   // Try to split the block so it's fully aligned.  Compute the latest split
   // point where we can add a 4-byte branch instruction, and then align to
   // LogAlign which is the largest possible alignment in the function.
-  unsigned LogAlign = MF->getLogAlignment();
+  unsigned LogAlign = Log2(MF->getAlignment());
   assert(LogAlign >= CPELogAlign && "Over-aligned constant pool entry");
   unsigned BaseInsertOffset = UserOffset + U.getMaxDisp();
   LLVM_DEBUG(dbgs() << format("Split in middle of big block before %#x",