[LLVM][Alignment] Make functions using log of alignment explicit

Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:

 - `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
 - `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
 - `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,

Reviewers: lattner, thegameg, courbet

Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65945

llvm-svn: 371045

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 7febb11dcb8..18efe1f80eb 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -197,7 +197,7 @@ void MIRPrinter::print(const MachineFunction &MF) {
 
   yaml::MachineFunction YamlMF;
   YamlMF.Name = MF.getName();
-  YamlMF.Alignment = MF.getAlignment();
+  YamlMF.Alignment = 1UL << MF.getLogAlignment();
   YamlMF.ExposesReturnsTwice = MF.exposesReturnsTwice();
   YamlMF.HasWinCFI = MF.hasWinCFI();
 
@@ -629,9 +629,10 @@ void MIPrinter::print(const MachineBasicBlock &MBB) {
     OS << "landing-pad";
     HasAttributes = true;
   }
-  if (MBB.getAlignment()) {
+  if (MBB.getLogAlignment()) {
     OS << (HasAttributes ? ", " : " (");
-    OS << "align " << MBB.getAlignment();
+    OS << "align "
+       << (1UL << MBB.getLogAlignment());
     HasAttributes = true;
   }
   if (HasAttributes)