MIR Serialization: Serialize the list of machine basic blocks with simple attributes.

This commit implements the initial serialization of machine basic blocks in a
machine function. Only the simple, scalar MBB attributes are serialized. The 
reference to LLVM IR's basic block is preserved when that basic block has a name.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10465


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240145 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MIRParser/MIRParser.cpp

@@ -19,10 +19,12 @@
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MIRYamlMapping.h"
+#include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/ValueSymbolTable.h"
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/SMLoc.h"
 #include "llvm/Support/SourceMgr.h"
@@ -74,6 +76,12 @@ public:
   /// Return true if error occurred.
   bool initializeMachineFunction(MachineFunction &MF);
 
+  /// Initialize the machine basic block using it's YAML representation.
+  ///
+  /// Return true if an error occurred.
+  bool initializeMachineBasicBlock(MachineBasicBlock &MBB,
+                                   const yaml::MachineBasicBlock &YamlMBB);
+
 private:
   /// Return a MIR diagnostic converted from an LLVM assembly diagnostic.
   SMDiagnostic diagFromLLVMAssemblyDiag(const SMDiagnostic &Error,
@@ -198,6 +206,28 @@ bool MIRParserImpl::initializeMachineFunction(MachineFunction &MF) {
     MF.setAlignment(YamlMF.Alignment);
   MF.setExposesReturnsTwice(YamlMF.ExposesReturnsTwice);
   MF.setHasInlineAsm(YamlMF.HasInlineAsm);
+  const auto &F = *MF.getFunction();
+  for (const auto &YamlMBB : YamlMF.BasicBlocks) {
+    const BasicBlock *BB = nullptr;
+    if (!YamlMBB.Name.empty()) {
+      BB = dyn_cast_or_null<BasicBlock>(
+          F.getValueSymbolTable().lookup(YamlMBB.Name));
+      // TODO: Report an error if a basic block isn't found.
+    }
+    auto *MBB = MF.CreateMachineBasicBlock(BB);
+    MF.insert(MF.end(), MBB);
+    if (initializeMachineBasicBlock(*MBB, YamlMBB))
+      return true;
+  }
+  return false;
+}
+
+bool MIRParserImpl::initializeMachineBasicBlock(
+    MachineBasicBlock &MBB, const yaml::MachineBasicBlock &YamlMBB) {
+  MBB.setAlignment(YamlMBB.Alignment);
+  if (YamlMBB.AddressTaken)
+    MBB.setHasAddressTaken();
+  MBB.setIsLandingPad(YamlMBB.IsLandingPad);
   return false;
 }