1 files changed, 114 insertions, 0 deletions
diff --git a/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp b/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
new file mode 100644
index 000000000000..4ebea68c58a5
--- /dev/null
+++ b/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
@@ -0,0 +1,114 @@
+//=- WebAssemblySetP2AlignOperands.cpp - Set alignments on loads and stores -=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file sets the p2align operands on load and store instructions.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssembly.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "WebAssemblyMachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
+#include "llvm/CodeGen/MachineMemOperand.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "wasm-set-p2align-operands"
+
+namespace {
+class WebAssemblySetP2AlignOperands final : public MachineFunctionPass {
+public:
+  static char ID; // Pass identification, replacement for typeid
+  WebAssemblySetP2AlignOperands() : MachineFunctionPass(ID) {}
+
+  const char *getPassName() const override {
+    return "WebAssembly Set p2align Operands";
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.setPreservesCFG();
+    AU.addPreserved<MachineBlockFrequencyInfo>();
+    AU.addPreservedID(MachineDominatorsID);
+    MachineFunctionPass::getAnalysisUsage(AU);
+  }
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+};
+} // end anonymous namespace
+
+char WebAssemblySetP2AlignOperands::ID = 0;
+FunctionPass *llvm::createWebAssemblySetP2AlignOperands() {
+  return new WebAssemblySetP2AlignOperands();
+}
+
+bool WebAssemblySetP2AlignOperands::runOnMachineFunction(MachineFunction &MF) {
+  DEBUG({
+    dbgs() << "********** Set p2align Operands **********\n"
+           << "********** Function: " << MF.getName() << '\n';
+  });
+
+  bool Changed = false;
+
+  for (auto &MBB : MF) {
+    for (auto &MI : MBB) {
+      switch (MI.getOpcode()) {
+      case WebAssembly::LOAD_I32:
+      case WebAssembly::LOAD_I64:
+      case WebAssembly::LOAD_F32:
+      case WebAssembly::LOAD_F64:
+      case WebAssembly::LOAD8_S_I32:
+      case WebAssembly::LOAD8_U_I32:
+      case WebAssembly::LOAD16_S_I32:
+      case WebAssembly::LOAD16_U_I32:
+      case WebAssembly::LOAD8_S_I64:
+      case WebAssembly::LOAD8_U_I64:
+      case WebAssembly::LOAD16_S_I64:
+      case WebAssembly::LOAD16_U_I64:
+      case WebAssembly::LOAD32_S_I64:
+      case WebAssembly::LOAD32_U_I64:
+      case WebAssembly::STORE_I32:
+      case WebAssembly::STORE_I64:
+      case WebAssembly::STORE_F32:
+      case WebAssembly::STORE_F64:
+      case WebAssembly::STORE8_I32:
+      case WebAssembly::STORE16_I32:
+      case WebAssembly::STORE8_I64:
+      case WebAssembly::STORE16_I64:
+      case WebAssembly::STORE32_I64: {
+        assert(MI.getOperand(3).getImm() == 0 &&
+               "ISel should set p2align operands to 0");
+        assert(MI.hasOneMemOperand() &&
+               "Load and store instructions have exactly one mem operand");
+        assert((*MI.memoperands_begin())->getSize() ==
+                   (UINT64_C(1)
+                    << WebAssembly::GetDefaultP2Align(MI.getOpcode())) &&
+               "Default p2align value should be natural");
+        assert(MI.getDesc().OpInfo[3].OperandType ==
+                   WebAssembly::OPERAND_P2ALIGN &&
+               "Load and store instructions should have a p2align operand");
+        uint64_t P2Align = Log2_64((*MI.memoperands_begin())->getAlignment());
+
+        // WebAssembly does not currently support supernatural alignment.
+        P2Align = std::min(
+            P2Align, uint64_t(WebAssembly::GetDefaultP2Align(MI.getOpcode())));
+
+        MI.getOperand(3).setImm(P2Align);
+        break;
+      }
+      default:
+        break;
+      }
+    }
+  }
+
+  return Changed;
+}