[FileCheck] Simplify numeric variable interface

Summary:
This patch simplifies 2 aspects in the FileCheckNumericVariable code.

First, setValue() method is turned into a void function since being
called only on undefined variable is an invariant and is now asserted
rather than returned. This remove the assert from the callers.

Second, clearValue() method is also turned into a void function since
the only caller does not check its return value since it may be trying
to clear the value of variable that is already cleared without this
being noteworthy.

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: JonChesterfield, rogfer01, hfinkel, kristina, rnk, tra, arichardson, grimar, dblaikie, probinson, llvm-commits, hiraditya

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64231

> llvm-svn: 365249

llvm-svn: 365625

llvm/include/llvm/Support/FileCheck.h

@@ -69,13 +69,13 @@ class FileCheckNumericVariable {
   /// \returns this variable's value.
   Optional<uint64_t> getValue() const { return Value; }
 
-  /// Sets value of this numeric variable if not defined. \returns whether the
-  /// variable was already defined.
-  bool setValue(uint64_t Value);
+  /// Sets value of this numeric variable, if undefined. Triggers an assertion
+  /// failure if the variable is actually defined.
+  void setValue(uint64_t Value);
 
-  /// Clears value of this numeric variable. \returns whether the variable was
-  /// already undefined.
-  bool clearValue();
+  /// Clears value of this numeric variable, regardless of whether it is
+  /// currently defined or not.
+  void clearValue();
 
   /// \returns the line number where this variable is defined.
   size_t getDefLineNumber() { return DefLineNumber; }

llvm/lib/Support/FileCheck.cpp

@@ -24,18 +24,15 @@
 
 using namespace llvm;
 
-bool FileCheckNumericVariable::setValue(uint64_t NewValue) {
-  if (Value)
-    return true;
+void FileCheckNumericVariable::setValue(uint64_t NewValue) {
+  assert(!Value && "Overwriting numeric variable's value is not allowed");
   Value = NewValue;
-  return false;
 }
 
-bool FileCheckNumericVariable::clearValue() {
+void FileCheckNumericVariable::clearValue() {
   if (!Value)
-    return true;
+    return;
   Value = None;
-  return false;
 }
 
 Expected<uint64_t> FileCheckExpression::eval() const {
@@ -625,8 +622,7 @@ Expected<size_t> FileCheckPattern::match(StringRef Buffer, size_t &MatchLen,
     if (MatchedValue.getAsInteger(10, Val))
       return FileCheckErrorDiagnostic::get(SM, MatchedValue,
                                            "Unable to represent numeric value");
-    if (DefinedNumericVariable->setValue(Val))
-      llvm_unreachable("Numeric variable redefined");
+    DefinedNumericVariable->setValue(Val);
   }
 
   // Like CHECK-NEXT, CHECK-EMPTY's match range is considered to start after

llvm/unittests/Support/FileCheckTest.cpp

@@ -15,28 +15,23 @@ namespace {
 class FileCheckTest : public ::testing::Test {};
 
 TEST_F(FileCheckTest, NumericVariable) {
-  // Undefined variable: getValue and clearValue fails, setValue works.
+  // Undefined variable: getValue fails, setValue does not trigger assert.
   FileCheckNumericVariable FooVar = FileCheckNumericVariable(1, "FOO");
   EXPECT_EQ("FOO", FooVar.getName());
   llvm::Optional<uint64_t> Value = FooVar.getValue();
   EXPECT_FALSE(Value);
-  EXPECT_TRUE(FooVar.clearValue());
-  EXPECT_FALSE(FooVar.setValue(42));
+  FooVar.clearValue();
+  FooVar.setValue(42);
 
-  // Defined variable: getValue returns value set, setValue fails.
-  Value = FooVar.getValue();
-  EXPECT_TRUE(Value);
-  EXPECT_EQ(42U, *Value);
-  EXPECT_TRUE(FooVar.setValue(43));
+  // Defined variable: getValue returns value set.
   Value = FooVar.getValue();
   EXPECT_TRUE(Value);
   EXPECT_EQ(42U, *Value);
 
-  // Clearing variable: getValue fails, clearValue again fails.
-  EXPECT_FALSE(FooVar.clearValue());
+  // Clearing variable: getValue fails.
+  FooVar.clearValue();
   Value = FooVar.getValue();
   EXPECT_FALSE(Value);
-  EXPECT_TRUE(FooVar.clearValue());
 }
 
 uint64_t doAdd(uint64_t OpL, uint64_t OpR) { return OpL + OpR; }