Basic Block Sections support in LLVM.

This is the second patch in a series of patches to enable basic block
sections support.

This patch adds support for:

* Creating direct jumps at the end of basic blocks that have fall
through instructions.
* New pass, bbsections-prepare, that analyzes placement of basic blocks
in sections.
* Actual placing of a basic block in a unique section with special
handling of exception handling blocks.
* Supports placing a subset of basic blocks in a unique section.
* Support for MIR serialization and deserialization with basic block
sections.

Parent patch : D68063
Differential Revision: https://reviews.llvm.org/D73674

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index ece4f96..1fb557e 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -635,6 +635,27 @@ void MIPrinter::print(const MachineBasicBlock &MBB) {
     OS << "align " << MBB.getAlignment().value();
     HasAttributes = true;
   }
+  if (MBB.getSectionType() != MBBS_None) {
+    OS << (HasAttributes ? ", " : " (");
+    OS << "bbsections ";
+    switch (MBB.getSectionType()) {
+    case MBBS_Entry:
+      OS << "Entry";
+      break;
+    case MBBS_Exception:
+      OS << "Exception";
+      break;
+    case MBBS_Cold:
+      OS << "Cold";
+      break;
+    case MBBS_Unique:
+      OS << "Unique";
+      break;
+    default:
+      llvm_unreachable("No such section type");
+    }
+    HasAttributes = true;
+  }
   if (HasAttributes)
     OS << ")";
   OS << ":\n";