[llvm] r297864 - [YAML] When outputting, provide the ability to write default values.

[Zachary Turner via llvm-commits]

Author: zturner
Date: Wed Mar 15 12:47:39 2017
New Revision: 297864

URL: http://llvm.org/viewvc/llvm-project?rev=297864&view=rev
Log:
[YAML] When outputting, provide the ability to write default values.

Previously, if you attempted to write a key/value pair and the
value was equal to the key's default value, we would not output
the value.  Sometimes it is useful to be able to see this value
in the output anyway.

Modified:
    llvm/trunk/include/llvm/Support/YAMLTraits.h
    llvm/trunk/lib/Support/YAMLTraits.cpp

Modified: llvm/trunk/include/llvm/Support/YAMLTraits.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/YAMLTraits.h?rev=297864&r1=297863&r2=297864&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/YAMLTraits.h (original)
+++ llvm/trunk/include/llvm/Support/YAMLTraits.h Wed Mar 15 12:47:39 2017
@@ -689,11 +689,12 @@ private:
     assert(DefaultValue.hasValue() == false &&
            "Optional<T> shouldn't have a value!");
     void *SaveInfo;
-    bool UseDefault;
+    bool UseDefault = true;
     const bool sameAsDefault = outputting() && !Val.hasValue();
     if (!outputting() && !Val.hasValue())
       Val = T();
-    if (this->preflightKey(Key, Required, sameAsDefault, UseDefault,
+    if (Val.hasValue() &&
+        this->preflightKey(Key, Required, sameAsDefault, UseDefault,
                            SaveInfo)) {
       yamlize(*this, Val.getValue(), Required, Ctx);
       this->postflightKey(SaveInfo);
@@ -731,7 +732,7 @@ private:
   }
 
 private:
-  void  *Ctxt;
+  void *Ctxt;
 };
 
 namespace detail {
@@ -1251,6 +1252,13 @@ public:
   Output(llvm::raw_ostream &, void *Ctxt = nullptr, int WrapColumn = 70);
   ~Output() override;
 
+  /// \brief Set whether or not to output optional values which are equal
+  /// to the default value.  By default, when outputting if you attempt
+  /// to write a value that is equal to the default, the value gets ignored.
+  /// Sometimes, it is useful to be able to see these in the resulting YAML
+  /// anyway.
+  void setWriteDefaultValues(bool Write) { WriteDefaultValues = Write; }
+
   bool outputting() override;
   bool mapTag(StringRef, bool) override;
   void beginMapping() override;
@@ -1314,6 +1322,7 @@ private:
   bool                     NeedFlowSequenceComma;
   bool                     EnumerationMatchFound;
   bool                     NeedsNewLine;
+  bool WriteDefaultValues;
 };
 
 /// YAML I/O does conversion based on types. But often native data types

Modified: llvm/trunk/lib/Support/YAMLTraits.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/YAMLTraits.cpp?rev=297864&r1=297863&r2=297864&view=diff
==============================================================================
--- llvm/trunk/lib/Support/YAMLTraits.cpp (original)
+++ llvm/trunk/lib/Support/YAMLTraits.cpp Wed Mar 15 12:47:39 2017
@@ -398,17 +398,10 @@ bool Input::canElideEmptySequence() {
 //===----------------------------------------------------------------------===//
 
 Output::Output(raw_ostream &yout, void *context, int WrapColumn)
-    : IO(context),
-      Out(yout),
-      WrapColumn(WrapColumn),
-      Column(0),
-      ColumnAtFlowStart(0),
-      ColumnAtMapFlowStart(0),
-      NeedBitValueComma(false),
-      NeedFlowSequenceComma(false),
-      EnumerationMatchFound(false),
-      NeedsNewLine(false) {
-}
+    : IO(context), Out(yout), WrapColumn(WrapColumn), Column(0),
+      ColumnAtFlowStart(0), ColumnAtMapFlowStart(0), NeedBitValueComma(false),
+      NeedFlowSequenceComma(false), EnumerationMatchFound(false),
+      NeedsNewLine(false), WriteDefaultValues(false) {}
 
 Output::~Output() {
 }
@@ -462,7 +455,7 @@ std::vector<StringRef> Output::keys() {
 bool Output::preflightKey(const char *Key, bool Required, bool SameAsDefault,
                           bool &UseDefault, void *&) {
   UseDefault = false;
-  if (Required || !SameAsDefault) {
+  if (Required || !SameAsDefault || WriteDefaultValues) {
     auto State = StateStack.back();
     if (State == inFlowMapFirstKey || State == inFlowMapOtherKey) {
       flowKey(Key);