[YAML] Fix YAML tags appearing before the start of sequence elements

Our existing yaml::Output code writes tags immediately when mapTag is called, without any state handling. This results in tags on sequence elements being written before the element itself. For example, we see this:

SomeArray:     !elem_type
  - key1:         1
    key2:         2 !elem_type2
  - key3:         3
    key4:         4

We should instead see:

SomeArray:
  - !elem_type
    key1:         1
    key2:         2
  - !elem_type2
    key3:         3
    key4:         4

Our reader handles reading properly, so this bug only impacts writing yaml sequences with tagged elements.

As a test for this I've modified the Mach-O yaml encoding to allways apply the !mach-o tag when encoding MachOYAML::Object entries. This results in the !mach-o tag appearing as expected in dumped fat files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274067 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/ObjectYAML/MachOYAML.cpp b/lib/ObjectYAML/MachOYAML.cpp
index 0a303a6e739db6af2eda4e2b125d5eb96a075734..d819e80836cea26d0b5275dedb4d4dd95c3fed3b 100644 (file)
--- a/lib/ObjectYAML/MachOYAML.cpp
+++ b/lib/ObjectYAML/MachOYAML.cpp
@@ -91,8 +91,8 @@ void MappingTraits<MachOYAML::Object>::mapping(IO &IO,
   // For Fat files there will be a different tag so they can be differentiated.
   if (!IO.getContext()) {
     IO.setContext(&Object);
-    IO.mapTag("!mach-o", true);
   }
+  IO.mapTag("!mach-o", true);
   IO.mapRequired("FileHeader", Object.Header);
   IO.mapOptional("LoadCommands", Object.LoadCommands);
   IO.mapOptional("LinkEditData", Object.LinkEdit);

diff --git a/lib/Support/YAMLTraits.cpp b/lib/Support/YAMLTraits.cpp
index 2aa6e9b7468333976e97d03919a7a09df41ffded..75fac20a8edb026c3d8cd166bb7cdb697ef5e5f3 100644 (file)
--- a/lib/Support/YAMLTraits.cpp
+++ b/lib/Support/YAMLTraits.cpp
@@ -423,8 +423,29 @@ void Output::beginMapping() {
 
 bool Output::mapTag(StringRef Tag, bool Use) {
   if (Use) {
-    this->output(" ");
+    // If this tag is being written inside a sequence we should write the start
+    // of the sequence before writing the tag, otherwise the tag won't be
+    // attached to the element in the sequence, but rather the sequence itself.
+    bool SequenceElement =
+        StateStack.size() > 1 && (StateStack[StateStack.size() - 2] == inSeq ||
+          StateStack[StateStack.size() - 2] == inFlowSeq);
+    if (SequenceElement && StateStack.back() == inMapFirstKey) {
+      this->newLineCheck();
+    } else {
+      this->output(" ");
+    }
     this->output(Tag);
+    if (SequenceElement) {
+      // If we're writing the tag during the first element of a map, the tag
+      // takes the place of the first element in the sequence.
+      if (StateStack.back() == inMapFirstKey) {
+        StateStack.pop_back();
+        StateStack.push_back(inMapOtherKey);
+      }
+      // Tags inside maps in sequences should act as keys in the map from a
+      // formatting perspective, so we always want a newline in a sequence.
+      NeedsNewLine = true;
+    }
   }
   return Use;
 }

diff --git a/test/ObjectYAML/MachO/fat_macho_i386_x86_64.yaml b/test/ObjectYAML/MachO/fat_macho_i386_x86_64.yaml
index 75043a9de746a140ebe2b7e40893234462b2427e..a3d566b920d52803430e5be35c156861cba8451a 100644 (file)
--- a/test/ObjectYAML/MachO/fat_macho_i386_x86_64.yaml
+++ b/test/ObjectYAML/MachO/fat_macho_i386_x86_64.yaml
@@ -52,7 +52,8 @@ Slices:
 #CHECK:     size:            15380
 #CHECK:     align:           12
 #CHECK: Slices:          
-#CHECK:   - FileHeader:      
+#CHECK:   - !mach-o
+#CHECK      FileHeader:      
 #CHECK:       magic:           0xFEEDFACE
 #CHECK:       cputype:         0x00000007
 #CHECK:       cpusubtype:      0x00000003
@@ -60,7 +61,8 @@ Slices:
 #CHECK:       ncmds:           0
 #CHECK:       sizeofcmds:      0
 #CHECK:       flags:           0x01218085
-#CHECK:   - FileHeader:      
+#CHECK:   - !mach-o
+#CHECK      FileHeader:        
 #CHECK:       magic:           0xFEEDFACF
 #CHECK:       cputype:         0x01000007
 #CHECK:       cpusubtype:      0x80000003