From cd9a9af6dd4f5d7bd7296d665c528b531dee9638 Mon Sep 17 00:00:00 2001
From: water111 <48171810+water111@users.noreply.github.com>
Date: Sun, 10 Jan 2021 11:08:03 -0500
Subject: [PATCH] fix register info duplication (#191)

---
 decompiler/IR2/AtomicOp.h                |  5 +++++
 decompiler/IR2/AtomicOpBuilder.cpp       | 17 +++++++++++------
 test/decompiler/test_AtomicOpBuilder.cpp | 21 +++++++++++++++++++++
 3 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/decompiler/IR2/AtomicOp.h b/decompiler/IR2/AtomicOp.h
index f31c867a2b..458def9988 100644
--- a/decompiler/IR2/AtomicOp.h
+++ b/decompiler/IR2/AtomicOp.h
@@ -125,6 +125,11 @@ class AtomicOp {
   const std::vector<Register>& write_regs() { return m_write_regs; }
   const std::vector<Register>& clobber_regs() { return m_clobber_regs; }
   void add_clobber_reg(Register r) { m_clobber_regs.push_back(r); }
+  void clear_register_info() {
+    m_read_regs.clear();
+    m_write_regs.clear();
+    m_clobber_regs.clear();
+  }
 
   virtual ~AtomicOp() = default;
 
diff --git a/decompiler/IR2/AtomicOpBuilder.cpp b/decompiler/IR2/AtomicOpBuilder.cpp
index 79f870867a..c4975bac23 100644
--- a/decompiler/IR2/AtomicOpBuilder.cpp
+++ b/decompiler/IR2/AtomicOpBuilder.cpp
@@ -1037,10 +1037,15 @@ std::unique_ptr<AtomicOp> convert_dsubu_3(const Instruction& i0,
   return nullptr;
 }
 
-void add_clobber_if_unritten(AtomicOp& op, Register clobber) {
+void add_clobber_if_unwritten(AtomicOp& op, Register clobber) {
   op.update_register_info();
+  std::vector<Register> clobber_regs = op.clobber_regs();
   if (std::find(op.write_regs().begin(), op.write_regs().end(), clobber) == op.write_regs().end()) {
-    op.add_clobber_reg(clobber);
+    clobber_regs.push_back(clobber);
+  }
+  op.clear_register_info();
+  for (auto& reg : clobber_regs) {
+    op.add_clobber_reg(reg);
   }
 }
 
@@ -1082,7 +1087,7 @@ std::unique_ptr<AtomicOp> convert_slt_3(const Instruction& i0,
       condition.invert();
     }
     result = make_branch(condition, i2, false, dest, idx);
-    add_clobber_if_unritten(*result, temp);
+    add_clobber_if_unwritten(*result, temp);
     return result;
   } else if (i1.kind == InstructionKind::DADDIU &&
              (i2.kind == InstructionKind::MOVZ || i2.kind == InstructionKind::MOVN)) {
@@ -1117,7 +1122,7 @@ std::unique_ptr<AtomicOp> convert_slt_3(const Instruction& i0,
       condition.invert();
     }
     result = std::make_unique<SetVarConditionOp>(make_dst_var(dest, idx), condition, idx);
-    add_clobber_if_unritten(*result, temp);
+    add_clobber_if_unwritten(*result, temp);
     return result;
   }
   return nullptr;
@@ -1147,7 +1152,7 @@ std::unique_ptr<AtomicOp> convert_slti_3(const Instruction& i0,
       condition.invert();
     }
     result = make_branch(condition, i2, false, dest, idx);
-    add_clobber_if_unritten(*result, temp);
+    add_clobber_if_unwritten(*result, temp);
     return result;
   } else if (i1.kind == InstructionKind::DADDIU &&
              (i2.kind == InstructionKind::MOVZ || i2.kind == InstructionKind::MOVN)) {
@@ -1172,7 +1177,7 @@ std::unique_ptr<AtomicOp> convert_slti_3(const Instruction& i0,
       condition.invert();
     }
     result = std::make_unique<SetVarConditionOp>(make_dst_var(dest, idx), condition, idx);
-    add_clobber_if_unritten(*result, temp);
+    add_clobber_if_unwritten(*result, temp);
     return result;
   }
   return nullptr;
diff --git a/test/decompiler/test_AtomicOpBuilder.cpp b/test/decompiler/test_AtomicOpBuilder.cpp
index ee78b69112..e1be81487e 100644
--- a/test/decompiler/test_AtomicOpBuilder.cpp
+++ b/test/decompiler/test_AtomicOpBuilder.cpp
@@ -118,6 +118,27 @@ void test_case(std::string assembly_lines,
   }
 }
 
+TEST(DecompilerAtomicOpBuilder, RegUseDuplication) {
+  auto assembly =
+      assembly_from_list({"L100:", "sltiu a3, a0, 12", "beq a3, r0, L100", "or a3, s7, r0"});
+
+  InstructionParser parser;
+  ParsedProgram prg = parser.parse_program(assembly);
+  EXPECT_EQ(prg.print(), assembly);
+  FunctionAtomicOps container;
+  convert_block_to_atomic_ops(0, prg.instructions.begin(), prg.instructions.end(), prg.labels,
+                              &container);
+  ASSERT_EQ(1, container.ops.size());
+  auto& op = container.ops.at(0);
+  for (const auto& reg_group : {op->read_regs(), op->write_regs(), op->clobber_regs()}) {
+    std::unordered_set<Register, Register::hash> unique_regs;
+    for (auto& reg : reg_group) {
+      unique_regs.insert(reg);
+    }
+    EXPECT_EQ(unique_regs.size(), reg_group.size());
+  }
+}
+
 TEST(DecompilerAtomicOpBuilder, Example) {
   test_case(assembly_from_list({"and v0, v1, a3", "and a1, a2, a2"}),
             {"(set! v0 (logand v1 a3))", "(set! a1 (logand a2 a2))"}, {{"v0"}, {"a1"}},