[Xtensa] Implement support for the BranchRelaxation. (#113450)

1 files changed, 31 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index b56888a..7eb1c5e 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -378,6 +378,37 @@ void MachineFunction::RenumberBlocks(MachineBasicBlock *MBB) {
   MBBNumberingEpoch++;
 }
 
+int64_t MachineFunction::estimateFunctionSizeInBytes() {
+  const TargetInstrInfo &TII = *getSubtarget().getInstrInfo();
+  const Align FunctionAlignment = getAlignment();
+  MachineFunction::iterator MBBI = begin(), E = end();
+  /// Offset - Distance from the beginning of the function to the end
+  /// of the basic block.
+  int64_t Offset = 0;
+
+  for (; MBBI != E; ++MBBI) {
+    const Align Alignment = MBBI->getAlignment();
+    int64_t BlockSize = 0;
+
+    for (auto &MI : *MBBI) {
+      BlockSize += TII.getInstSizeInBytes(MI);
+    }
+
+    int64_t OffsetBB;
+    if (Alignment <= FunctionAlignment) {
+      OffsetBB = alignTo(Offset, Alignment);
+    } else {
+      // The alignment of this MBB is larger than the function's alignment, so
+      // we can't tell whether or not it will insert nops. Assume that it will.
+      OffsetBB = alignTo(Offset, Alignment) + Alignment.value() -
+                 FunctionAlignment.value();
+    }
+    Offset = OffsetBB + BlockSize;
+  }
+
+  return Offset;
+}
+
 /// This method iterates over the basic blocks and assigns their IsBeginSection
 /// and IsEndSection fields. This must be called after MBB layout is finalized
 /// and the SectionID's are assigned to MBBs.