[MLIR][LLVM] Support for indirectbr (#135092)

Now that LLVM dialect has `blockaddress` support, introduce import/translation for `indirectbr` instruction.

1 files changed, 31 insertions, 2 deletions

diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
index 8e7a7ab..346a0ed 100644
--- a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -1988,6 +1988,35 @@ LogicalResult ModuleImport::convertInstruction(llvm::Instruction *inst) {
     return success();
   }
 
+  if (inst->getOpcode() == llvm::Instruction::IndirectBr) {
+    auto *indBrInst = cast<llvm::IndirectBrInst>(inst);
+
+    FailureOr<Value> basePtr = convertValue(indBrInst->getAddress());
+    if (failed(basePtr))
+      return failure();
+
+    SmallVector<Block *> succBlocks;
+    // `succBlockArgs` is storage for the block arguments ranges used in
+    // `succBlockArgsRange`, so the later references live data.
+    SmallVector<SmallVector<Value>> succBlockArgs;
+    SmallVector<ValueRange> succBlockArgsRange;
+    for (auto i : llvm::seq<unsigned>(0, indBrInst->getNumSuccessors())) {
+      llvm::BasicBlock *succ = indBrInst->getSuccessor(i);
+      SmallVector<Value> blockArgs;
+      if (failed(convertBranchArgs(indBrInst, succ, blockArgs)))
+        return failure();
+      succBlocks.push_back(lookupBlock(succ));
+      succBlockArgs.push_back(blockArgs);
+      succBlockArgsRange.push_back(succBlockArgs.back());
+    }
+    Location loc = translateLoc(inst->getDebugLoc());
+    auto indBrOp = builder.create<LLVM::IndirectBrOp>(
+        loc, *basePtr, succBlockArgsRange, succBlocks);
+
+    mapNoResultOp(inst, indBrOp);
+    return success();
+  }
+
   // Convert all instructions that have an mlirBuilder.
   if (succeeded(convertInstructionImpl(builder, inst, *this, iface)))
     return success();
@@ -1998,8 +2027,8 @@ LogicalResult ModuleImport::convertInstruction(llvm::Instruction *inst) {
 LogicalResult ModuleImport::processInstruction(llvm::Instruction *inst) {
   // FIXME: Support uses of SubtargetData.
   // FIXME: Add support for call / operand attributes.
-  // FIXME: Add support for the indirectbr, cleanupret, catchret, catchswitch,
-  // callbr, vaarg, catchpad, cleanuppad instructions.
+  // FIXME: Add support for the cleanupret, catchret, catchswitch, callbr,
+  // vaarg, catchpad, cleanuppad instructions.
 
   // Convert LLVM intrinsics calls to MLIR intrinsics.
   if (auto *intrinsic = dyn_cast<llvm::IntrinsicInst>(inst))