Reapply [memprof] Update YAML traits for writer purposes (llvm#118720)

For Frames, we prefer the inline notation for the brevity.

For PortableMemInfoBlock, we go through all member fields and print
out those that are populated.

This iteration works around the unavailability of
ScalarTraits<uintptr_t> on macOS.

Author: kazutakahirata

llvm/include/llvm/ProfileData/MemProf.h

@@ -1183,6 +1183,10 @@ template <> struct MappingTraits<memprof::Frame> {
     (void)Column;
     (void)IsInlineFrame;
   }
+
+  // Request the inline notation for brevity:
+  //   { Function: 123, LineOffset: 11, Column: 10; IsInlineFrame: true }
+  static const bool flow = true;
 };
 
 template <> struct CustomMappingTraits<memprof::PortableMemInfoBlock> {
@@ -1207,8 +1211,15 @@ template <> struct CustomMappingTraits<memprof::PortableMemInfoBlock> {
     Io.setError("Key is not a valid validation event");
   }
 
-  static void output(IO &Io, memprof::PortableMemInfoBlock &VI) {
-    llvm_unreachable("To be implemented");
+  static void output(IO &Io, memprof::PortableMemInfoBlock &MIB) {
+    auto Schema = MIB.getSchema();
+#define MIBEntryDef(NameTag, Name, Type)                                       \
+  if (Schema.test(llvm::to_underlying(memprof::Meta::Name))) {                 \
+    uint64_t Value = MIB.Name;                                                 \
+    Io.mapRequired(#Name, Value);                                              \
+  }
+#include "llvm/ProfileData/MIBEntryDef.inc"
+#undef MIBEntryDef
   }
 };
 

llvm/unittests/ProfileData/MemProfTest.cpp

@@ -807,4 +807,40 @@ TEST(MemProf, YAMLParser) {
   EXPECT_THAT(Record.CallSiteIds,
               ElementsAre(hashCallStack(CS3), hashCallStack(CS4)));
 }
+
+template <typename T> std::string serializeInYAML(T &Val) {
+  std::string Out;
+  llvm::raw_string_ostream OS(Out);
+  llvm::yaml::Output Yout(OS);
+  Yout << Val;
+  return Out;
+}
+
+TEST(MemProf, YAMLWriterFrame) {
+  Frame F(11, 22, 33, true);
+
+  std::string Out = serializeInYAML(F);
+  EXPECT_EQ(Out, R"YAML(---
+{ Function: 11, LineOffset: 22, Column: 33, Inline: true }
+...
+)YAML");
+}
+
+TEST(MemProf, YAMLWriterMIB) {
+  MemInfoBlock MIB;
+  MIB.AllocCount = 111;
+  MIB.TotalSize = 222;
+  MIB.TotalLifetime = 333;
+  MIB.TotalLifetimeAccessDensity = 444;
+  PortableMemInfoBlock PMIB(MIB, llvm::memprof::getHotColdSchema());
+
+  std::string Out = serializeInYAML(PMIB);
+  EXPECT_EQ(Out, R"YAML(---
+AllocCount:      111
+TotalSize:       222
+TotalLifetime:   333
+TotalLifetimeAccessDensity: 444
+...
+)YAML");
+}
 } // namespace