[WebAssembly] Fix updating/moving DBG_VALUEs in RegStackify

Summary:
As described in PR40209, there can be issues in DBG_VALUEs handling when multiple defs present in a BB. This patch
adds logic for detection of related to def DBG_VALUEs and localizes register update and movement to found DBG_VALUEs.

Reviewers: aheejin

Subscribers: mgorny, dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56401

llvm-svn: 351216

1 files changed, 46 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.cpp
new file mode 100644
index 0000000..8ecc159
--- /dev/null
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyDebugValueManager.cpp
@@ -0,0 +1,46 @@
+//===-- WebAssemblyDebugValueManager.cpp - WebAssembly DebugValue Manager -===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements the manager for MachineInstr DebugValues.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssemblyDebugValueManager.h"
+#include "WebAssemblyMachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineInstr.h"
+
+using namespace llvm;
+
+WebAssemblyDebugValueManager::WebAssemblyDebugValueManager(
+    MachineInstr *Instr) {
+  Instr->collectDebugValues(DbgValues);
+}
+
+void WebAssemblyDebugValueManager::move(MachineInstr *Insert) {
+  MachineBasicBlock *MBB = Insert->getParent();
+  for (MachineInstr *DBI : reverse(DbgValues))
+    MBB->splice(Insert, DBI->getParent(), DBI);
+}
+
+void WebAssemblyDebugValueManager::updateReg(unsigned Reg) {
+  for (auto *DBI : DbgValues)
+    DBI->getOperand(0).setReg(Reg);
+}
+
+void WebAssemblyDebugValueManager::clone(MachineInstr *Insert,
+                                         unsigned NewReg) {
+  MachineBasicBlock *MBB = Insert->getParent();
+  MachineFunction *MF = MBB->getParent();
+  for (MachineInstr *DBI : reverse(DbgValues)) {
+    MachineInstr *Clone = MF->CloneMachineInstr(DBI);
+    Clone->getOperand(0).setReg(NewReg);
+    MBB->insert(Insert, Clone);
+  }
+}