IR: Expose the method 'getLocalSlot' in the module slot tracker.

This commit publicly exposes the method 'getLocalSlot' in the
'ModuleSlotTracker' class.

This change is useful for MIR serialization, to serialize the unnamed basic
block and unnamed alloca references.

Reviewers: Duncan P. N. Exon Smith
llvm-svn: 243336

llvm/include/llvm/IR/ModuleSlotTracker.h

@@ -17,6 +17,7 @@ namespace llvm {
 class Module;
 class Function;
 class SlotTracker;
+class Value;
 
 /// Manage lifetime of a slot tracker for printing IR.
 ///
@@ -61,6 +62,13 @@ public:
   /// Purge the currently incorporated function and incorporate \c F.  If \c F
   /// is currently incorporated, this is a no-op.
   void incorporateFunction(const Function &F);
+
+  /// Return the slot number of the specified local value.
+  ///
+  /// A function that defines this value should be incorporated prior to calling
+  /// this method.
+  /// Return -1 if the value is not in the function's SlotTracker.
+  int getLocalSlot(const Value *V);
 };
 
 } // end namespace llvm

llvm/lib/IR/AsmWriter.cpp

@@ -702,6 +702,11 @@ void ModuleSlotTracker::incorporateFunction(const Function &F) {
   this->F = &F;
 }
 
+int ModuleSlotTracker::getLocalSlot(const Value *V) {
+  assert(F && "No function incorporated");
+  return Machine->getLocalSlot(V);
+}
+
 static SlotTracker *createSlotTracker(const Module *M) {
   return new SlotTracker(M);
 }

llvm/unittests/IR/ValueTest.cpp

@@ -175,4 +175,64 @@ TEST(ValueTest, printSlots) {
 #undef CHECK_PRINT_AS_OPERAND
 }
 
+TEST(ValueTest, getLocalSlots) {
+  // Verify that the getLocalSlot method returns the correct slot numbers.
+  LLVMContext C;
+  const char *ModuleString = "define void @f(i32 %x, i32 %y) {\n"
+                             "entry:\n"
+                             "  %0 = add i32 %y, 1\n"
+                             "  %1 = add i32 %y, 1\n"
+                             "  br label %2\n"
+                             "\n"
+                             "  ret void\n"
+                             "}\n";
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M = parseAssemblyString(ModuleString, Err, C);
+
+  Function *F = M->getFunction("f");
+  ASSERT_TRUE(F);
+  ASSERT_FALSE(F->empty());
+  BasicBlock &EntryBB = F->getEntryBlock();
+  ASSERT_EQ(3u, EntryBB.size());
+  BasicBlock *BB2 = ++F->begin();
+  ASSERT_TRUE(BB2);
+
+  Instruction *I0 = EntryBB.begin();
+  ASSERT_TRUE(I0);
+  Instruction *I1 = ++EntryBB.begin();
+  ASSERT_TRUE(I1);
+
+  ModuleSlotTracker MST(M.get());
+  MST.incorporateFunction(*F);
+  EXPECT_EQ(MST.getLocalSlot(I0), 0);
+  EXPECT_EQ(MST.getLocalSlot(I1), 1);
+  EXPECT_EQ(MST.getLocalSlot(&EntryBB), -1);
+  EXPECT_EQ(MST.getLocalSlot(BB2), 2);
+}
+
+#if defined(GTEST_HAS_DEATH_TEST) && !defined(NDEBUG)
+TEST(ValueTest, getLocalSlotDeath) {
+  LLVMContext C;
+  const char *ModuleString = "define void @f(i32 %x, i32 %y) {\n"
+                             "entry:\n"
+                             "  %0 = add i32 %y, 1\n"
+                             "  %1 = add i32 %y, 1\n"
+                             "  br label %2\n"
+                             "\n"
+                             "  ret void\n"
+                             "}\n";
+  SMDiagnostic Err;
+  std::unique_ptr<Module> M = parseAssemblyString(ModuleString, Err, C);
+
+  Function *F = M->getFunction("f");
+  ASSERT_TRUE(F);
+  ASSERT_FALSE(F->empty());
+  BasicBlock *BB2 = ++F->begin();
+  ASSERT_TRUE(BB2);
+
+  ModuleSlotTracker MST(M.get());
+  EXPECT_DEATH(MST.getLocalSlot(BB2), "No function incorporated");
+}
+#endif
+
 } // end anonymous namespace