Added lowering pass

3 files changed, 84 insertions, 0 deletions

diff --git a/lib/Core/Executor.cpp b/lib/Core/Executor.cpp
index 0506b685..7c4ee23a 100644
--- a/lib/Core/Executor.cpp
+++ b/lib/Core/Executor.cpp
@@ -2566,6 +2566,15 @@ void Executor::executeInstruction(ExecutionState &state, KInstruction *ki) {
     // instructions.
     terminateStateOnExecError(state, "Unexpected ShuffleVector instruction");
     break;
+  case Instruction::AtomicRMW:
+    terminateStateOnExecError(state, "Unexpected Atomic instruction, should be "
+                                     "lowered by LowerAtomicInstructionPass");
+    break;
+  case Instruction::AtomicCmpXchg:
+    terminateStateOnExecError(state,
+                              "Unexpected AtomicCmpXchg instruction, should be "
+                              "lowered by LowerAtomicInstructionPass");
+    break;
   // Other instructions...
   // Unhandled
   default:
diff --git a/lib/Module/KModule.cpp b/lib/Module/KModule.cpp
index 7b02c856..b025c888 100644
--- a/lib/Module/KModule.cpp
+++ b/lib/Module/KModule.cpp
@@ -224,6 +224,9 @@ void KModule::instrument(const Interpreter::ModuleOptions &opts) {
   // NOTE: Must come before division/overshift checks because those passes
   // don't know how to handle vector instructions.
   pm.add(createScalarizerPass());
+
+  // This pass will replace atomic instructions with non-atomic operations
+  pm.add(createLowerAtomicPass());
   if (opts.CheckDivZero) pm.add(new DivCheckPass());
   if (opts.CheckOvershift) pm.add(new OvershiftCheckPass());
 
diff --git a/test/Feature/Atomic.c b/test/Feature/Atomic.c
new file mode 100644
index 00000000..8b729de7
--- /dev/null
+++ b/test/Feature/Atomic.c
@@ -0,0 +1,72 @@
+// REQUIRES: geq-llvm-3.7
+// RUN: %llvmgcc %s -emit-llvm -g -c -o %t.bc
+// RUN: rm -rf %t.klee-out
+// RUN: %klee --output-dir=%t.klee-out --exit-on-error %t.bc 2>%t.log
+// RUN: cat %t.klee-out/assembly.ll | FileCheck %s
+
+// Checks that KLEE lowers atomic instructions to non-atomic operations
+
+#include <assert.h>
+#include <stdatomic.h>
+
+void test_add() {
+  atomic_int a = 7;
+  atomic_fetch_add(&a, 7);
+  // CHECK-NOT: atomicrmw add
+  assert(a == 14);
+}
+
+void test_sub() {
+  atomic_int a = 7;
+  atomic_fetch_sub(&a, 7);
+  // CHECK-NOT: atomicrmw sub
+  assert(a == 0);
+}
+
+void test_and() {
+  atomic_int a = 0b10001;
+  atomic_fetch_and(&a, 0b00101);
+  // CHECK-NOT: atomicrmw and
+  assert(a == 0b00001);
+}
+
+void test_or() {
+  atomic_int a = 0b10001;
+  atomic_fetch_or(&a, 0b00101);
+  // CHECK-NOT: atomicrmw or
+  assert(a == 0b10101);
+}
+
+void test_xor() {
+  atomic_int a = 0b10001;
+  atomic_fetch_xor(&a, 0b00101);
+  // CHECK-NOT: atomicrmw xor
+  assert(a == 0b10100);
+}
+
+void test_xchg() {
+  atomic_int a = 7;
+  atomic_exchange(&a, 10);
+  // CHECK-NOT: atomicrmw xchg
+  assert(a == 10);
+}
+
+void test_cmp_xchg() {
+  atomic_int a = 7;
+  int b = 7;
+  atomic_compare_exchange_weak(&a, &b, 10);
+  // CHECK-NOT: cmpxchg weak
+  assert(a == 10);
+  assert(b == 7);
+}
+
+int main() {
+  test_and();
+  test_sub();
+  test_and();
+  test_or();
+  test_xor();
+  test_xchg();
+  test_cmp_xchg();
+  return 0;
+}