[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, 2 insertions, 2 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp b/llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp
index ee93739b2c7..fec081d324e 100644
--- a/llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonBranchRelaxation.cpp
@@ -105,11 +105,11 @@ void HexagonBranchRelaxation::computeOffset(MachineFunction &MF,
   // offset of the current instruction from the start.
   unsigned InstOffset = 0;
   for (auto &B : MF) {
-    if (B.getAlignment()) {
+    if (B.getLogAlignment()) {
       // Although we don't know the exact layout of the final code, we need
       // to account for alignment padding somehow. This heuristic pads each
       // aligned basic block according to the alignment value.
-      int ByteAlign = (1u << B.getAlignment()) - 1;
+      int ByteAlign = (1u << B.getLogAlignment()) - 1;
       InstOffset = (InstOffset + ByteAlign) & ~(ByteAlign);
     }
     OffsetMap[&B] = InstOffset;