Object: Provide a richer means of describing auxiliary symbols

The current state of affairs has auxiliary symbols described as a big
bag of bytes. This is less than satisfying, it detracts from the YAML
file as being human readable.

Instead, allow for symbols to optionally contain their auxiliary data.
This allows us to have a much higher level way of describing things like
weak symbols, function definitions and section definitions.

This depends on D3105.

Differential Revision: http://llvm-reviews.chandlerc.com/D3092

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204214 91177308-0d34-0410-b5e6-96231b3b80d8

14 files changed, 457 insertions, 54 deletions

diff --git a/include/llvm/Object/COFF.h b/include/llvm/Object/COFF.h
index 4d5783ddce..67afe35ae9 100644
--- a/include/llvm/Object/COFF.h
+++ b/include/llvm/Object/COFF.h
@@ -202,6 +202,37 @@ struct coff_symbol {
   uint8_t getBaseType() const { return Type & 0x0F; }
 
   uint8_t getComplexType() const { return (Type & 0xF0) >> 4; }
+
+  bool isFunctionDefinition() const {
+    return StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
+           getBaseType() == COFF::IMAGE_SYM_TYPE_NULL &&
+           getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION &&
+           COFF::isReservedSectionNumber(SectionNumber);
+  }
+
+  bool isWeakExternal() const {
+    return StorageClass == COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL ||
+           (StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
+            SectionNumber == COFF::IMAGE_SYM_UNDEFINED && Value == 0);
+  }
+
+  bool isFileRecord() const {
+    return StorageClass == COFF::IMAGE_SYM_CLASS_FILE;
+  }
+
+  bool isSectionDefinition() const {
+    // C++/CLI creates external ABS symbols for non-const appdomain globals.
+    // These are also followed by an auxiliary section definition.
+    bool isAppdomainGlobal = StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
+                             SectionNumber == COFF::IMAGE_SYM_ABSOLUTE;
+    bool isOrdinarySection =
+        StorageClass == COFF::IMAGE_SYM_CLASS_STATIC && Value == 0;
+    return isAppdomainGlobal || isOrdinarySection;
+  }
+
+  bool isCLRToken() const {
+    return StorageClass == COFF::IMAGE_SYM_CLASS_CLR_TOKEN;
+  }
 };
 
 struct coff_section {
diff --git a/include/llvm/Object/COFFYAML.h b/include/llvm/Object/COFFYAML.h
index 3fa3ec6c12..b5f9cccf85 100644
--- a/include/llvm/Object/COFFYAML.h
+++ b/include/llvm/Object/COFFYAML.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_OBJECT_COFFYAML_H
 #define LLVM_OBJECT_COFFYAML_H
 
+#include "llvm/ADT/Optional.h"
 #include "llvm/Object/YAML.h"
 #include "llvm/Support/COFF.h"
 
@@ -35,6 +36,10 @@ inline SectionCharacteristics operator|(SectionCharacteristics a,
 // The structure of the yaml files is not an exact 1:1 match to COFF. In order
 // to use yaml::IO, we use these structures which are closer to the source.
 namespace COFFYAML {
+  LLVM_YAML_STRONG_TYPEDEF(uint8_t, COMDATType)
+  LLVM_YAML_STRONG_TYPEDEF(uint32_t, WeakExternalCharacteristics)
+  LLVM_YAML_STRONG_TYPEDEF(uint8_t, AuxSymbolType)
+
   struct Relocation {
     uint32_t VirtualAddress;
     uint16_t Type;
@@ -54,7 +59,12 @@ namespace COFFYAML {
     COFF::symbol Header;
     COFF::SymbolBaseType SimpleType;
     COFF::SymbolComplexType ComplexType;
-    object::yaml::BinaryRef AuxiliaryData;
+    Optional<COFF::AuxiliaryFunctionDefinition> FunctionDefinition;
+    Optional<COFF::AuxiliarybfAndefSymbol> bfAndefSymbol;
+    Optional<COFF::AuxiliaryWeakExternal> WeakExternal;
+    StringRef File;
+    Optional<COFF::AuxiliarySectionDefinition> SectionDefinition;
+    Optional<COFF::AuxiliaryCLRToken> CLRToken;
     StringRef Name;
     Symbol();
   };
@@ -76,6 +86,21 @@ namespace llvm {
 namespace yaml {
 
 template <>
+struct ScalarEnumerationTraits<COFFYAML::WeakExternalCharacteristics> {
+  static void enumeration(IO &IO, COFFYAML::WeakExternalCharacteristics &Value);
+};
+
+template <>
+struct ScalarEnumerationTraits<COFFYAML::AuxSymbolType> {
+  static void enumeration(IO &IO, COFFYAML::AuxSymbolType &Value);
+};
+
+template <>
+struct ScalarEnumerationTraits<COFFYAML::COMDATType> {
+  static void enumeration(IO &IO, COFFYAML::COMDATType &Value);
+};
+
+template <>
 struct ScalarEnumerationTraits<COFF::MachineTypes> {
   static void enumeration(IO &IO, COFF::MachineTypes &Value);
 };
@@ -120,6 +145,26 @@ struct MappingTraits<COFF::header> {
   static void mapping(IO &IO, COFF::header &H);
 };
 
+template <> struct MappingTraits<COFF::AuxiliaryFunctionDefinition> {
+  static void mapping(IO &IO, COFF::AuxiliaryFunctionDefinition &AFD);
+};
+
+template <> struct MappingTraits<COFF::AuxiliarybfAndefSymbol> {
+  static void mapping(IO &IO, COFF::AuxiliarybfAndefSymbol &AAS);
+};
+
+template <> struct MappingTraits<COFF::AuxiliaryWeakExternal> {
+  static void mapping(IO &IO, COFF::AuxiliaryWeakExternal &AWE);
+};
+
+template <> struct MappingTraits<COFF::AuxiliarySectionDefinition> {
+  static void mapping(IO &IO, COFF::AuxiliarySectionDefinition &ASD);
+};
+
+template <> struct MappingTraits<COFF::AuxiliaryCLRToken> {
+  static void mapping(IO &IO, COFF::AuxiliaryCLRToken &ACT);
+};
+
 template <>
 struct MappingTraits<COFFYAML::Symbol> {
   static void mapping(IO &IO, COFFYAML::Symbol &S);
diff --git a/include/llvm/Support/COFF.h b/include/llvm/Support/COFF.h
index 5586253309..dca7fc6ee8 100644
--- a/include/llvm/Support/COFF.h
+++ b/include/llvm/Support/COFF.h
@@ -212,6 +212,10 @@ namespace COFF {
     SCT_COMPLEX_TYPE_SHIFT   = 4
   };
 
+  enum AuxSymbolType {
+    IMAGE_AUX_SYMBOL_TYPE_TOKEN_DEF = 1
+  };
+
   struct section {
     char     Name[NameSize];
     uint32_t VirtualSize;
@@ -337,7 +341,7 @@ namespace COFF {
     uint32_t TotalSize;
     uint32_t PointerToLinenumber;
     uint32_t PointerToNextFunction;
-    uint8_t  unused[2];
+    char     unused[2];
   };
 
   struct AuxiliarybfAndefSymbol {
@@ -372,7 +376,14 @@ namespace COFF {
     uint32_t CheckSum;
     uint16_t Number;
     uint8_t  Selection;
-    uint8_t  unused[3];
+    char     unused[3];
+  };
+
+  struct AuxiliaryCLRToken {
+    uint8_t  AuxType;
+    uint8_t  unused1;
+    uint32_t SymbolTableIndex;
+    char     unused2[12];
   };
 
   union Auxiliary {
diff --git a/include/llvm/Support/YAMLTraits.h b/include/llvm/Support/YAMLTraits.h
index e704bf17fe..ea217c39fc 100644
--- a/include/llvm/Support/YAMLTraits.h
+++ b/include/llvm/Support/YAMLTraits.h
@@ -13,6 +13,7 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
@@ -421,6 +422,11 @@ public:
   }
 
   template <typename T>
+  void mapOptional(const char* Key, Optional<T> &Val) {
+    processKeyWithDefault(Key, Val, Optional<T>(), /*Required=*/false);
+  }
+
+  template <typename T>
   typename std::enable_if<!has_SequenceTraits<T>::value,void>::type
   mapOptional(const char* Key, T& Val) {
     this->processKey(Key, Val, false);
@@ -433,6 +439,26 @@ public:
   
 private:
   template <typename T>
+  void processKeyWithDefault(const char *Key, Optional<T> &Val,
+                             const Optional<T> &DefaultValue, bool Required) {
+    assert(DefaultValue.hasValue() == false &&
+           "Optional<T> shouldn't have a value!");
+    void *SaveInfo;
+    bool UseDefault;
+    const bool sameAsDefault = outputting() && !Val.hasValue();
+    if (!outputting() && !Val.hasValue())
+      Val = T();
+    if (this->preflightKey(Key, Required, sameAsDefault, UseDefault,
+                           SaveInfo)) {
+      yamlize(*this, Val.getValue(), Required);
+      this->postflightKey(SaveInfo);
+    } else {
+      if (UseDefault)
+        Val = DefaultValue;
+    }
+  }
+
+  template <typename T>
   void processKeyWithDefault(const char *Key, T &Val, const T& DefaultValue,
                                                                 bool Required) {
     void *SaveInfo;
diff --git a/lib/Object/COFFObjectFile.cpp b/lib/Object/COFFObjectFile.cpp
index 039bc4ef48..8036ab1812 100644
--- a/lib/Object/COFFObjectFile.cpp
+++ b/lib/Object/COFFObjectFile.cpp
@@ -174,7 +174,7 @@ error_code COFFObjectFile::getSymbolType(DataRefImpl Ref,
   if (Symb->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
       Symb->SectionNumber == COFF::IMAGE_SYM_UNDEFINED) {
     Result = SymbolRef::ST_Unknown;
-  } else if (Symb->getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION) {
+  } else if (Symb->isFunctionDefinition()) {
     Result = SymbolRef::ST_Function;
   } else {
     uint32_t Characteristics = 0;
diff --git a/lib/Object/COFFYAML.cpp b/lib/Object/COFFYAML.cpp
index 2a0c07a391..94b72ffcbf 100644
--- a/lib/Object/COFFYAML.cpp
+++ b/lib/Object/COFFYAML.cpp
@@ -23,6 +23,31 @@ Object::Object() { memset(&Header, 0, sizeof(COFF::header)); }
 }
 
 namespace yaml {
+void ScalarEnumerationTraits<COFFYAML::COMDATType>::enumeration(
+    IO &IO, COFFYAML::COMDATType &Value) {
+  IO.enumCase(Value, "0", 0);
+  ECase(IMAGE_COMDAT_SELECT_NODUPLICATES);
+  ECase(IMAGE_COMDAT_SELECT_ANY);
+  ECase(IMAGE_COMDAT_SELECT_SAME_SIZE);
+  ECase(IMAGE_COMDAT_SELECT_EXACT_MATCH);
+  ECase(IMAGE_COMDAT_SELECT_ASSOCIATIVE);
+  ECase(IMAGE_COMDAT_SELECT_LARGEST);
+  ECase(IMAGE_COMDAT_SELECT_NEWEST);
+}
+
+void
+ScalarEnumerationTraits<COFFYAML::WeakExternalCharacteristics>::enumeration(
+    IO &IO, COFFYAML::WeakExternalCharacteristics &Value) {
+  ECase(IMAGE_WEAK_EXTERN_SEARCH_NOLIBRARY);
+  ECase(IMAGE_WEAK_EXTERN_SEARCH_LIBRARY);
+  ECase(IMAGE_WEAK_EXTERN_SEARCH_ALIAS);
+}
+
+void ScalarEnumerationTraits<COFFYAML::AuxSymbolType>::enumeration(
+    IO &IO, COFFYAML::AuxSymbolType &Value) {
+  ECase(IMAGE_AUX_SYMBOL_TYPE_TOKEN_DEF);
+}
+
 void ScalarEnumerationTraits<COFF::MachineTypes>::enumeration(
     IO &IO, COFF::MachineTypes &Value) {
   ECase(IMAGE_FILE_MACHINE_UNKNOWN);
@@ -187,6 +212,24 @@ void ScalarBitSetTraits<COFF::SectionCharacteristics>::bitset(
 #undef BCase
 
 namespace {
+struct NSectionSelectionType {
+  NSectionSelectionType(IO &)
+      : SelectionType(COFFYAML::COMDATType(0)) {}
+  NSectionSelectionType(IO &, uint8_t C)
+      : SelectionType(COFFYAML::COMDATType(C)) {}
+  uint8_t denormalize(IO &) { return SelectionType; }
+  COFFYAML::COMDATType SelectionType;
+};
+
+struct NWeakExternalCharacteristics {
+  NWeakExternalCharacteristics(IO &)
+      : Characteristics(COFFYAML::WeakExternalCharacteristics(0)) {}
+  NWeakExternalCharacteristics(IO &, uint32_t C)
+      : Characteristics(COFFYAML::WeakExternalCharacteristics(C)) {}
+  uint32_t denormalize(IO &) { return Characteristics; }
+  COFFYAML::WeakExternalCharacteristics Characteristics;
+};
+
 struct NSectionCharacteristics {
   NSectionCharacteristics(IO &)
       : Characteristics(COFF::SectionCharacteristics(0)) {}
@@ -196,6 +239,15 @@ struct NSectionCharacteristics {
   COFF::SectionCharacteristics Characteristics;
 };
 
+struct NAuxTokenType {
+  NAuxTokenType(IO &)
+      : AuxType(COFFYAML::AuxSymbolType(0)) {}
+  NAuxTokenType(IO &, uint8_t C)
+      : AuxType(COFFYAML::AuxSymbolType(C)) {}
+  uint32_t denormalize(IO &) { return AuxType; }
+  COFFYAML::AuxSymbolType AuxType;
+};
+
 struct NStorageClass {
   NStorageClass(IO &) : StorageClass(COFF::SymbolStorageClass(0)) {}
   NStorageClass(IO &, uint8_t S) : StorageClass(COFF::SymbolStorageClass(S)) {}
@@ -247,6 +299,48 @@ void MappingTraits<COFF::header>::mapping(IO &IO, COFF::header &H) {
   IO.mapOptional("Characteristics", NC->Characteristics);
 }
 
+void MappingTraits<COFF::AuxiliaryFunctionDefinition>::mapping(
+    IO &IO, COFF::AuxiliaryFunctionDefinition &AFD) {
+  IO.mapRequired("TagIndex", AFD.TagIndex);
+  IO.mapRequired("TotalSize", AFD.TotalSize);
+  IO.mapRequired("PointerToLinenumber", AFD.PointerToLinenumber);
+  IO.mapRequired("PointerToNextFunction", AFD.PointerToNextFunction);
+}
+
+void MappingTraits<COFF::AuxiliarybfAndefSymbol>::mapping(
+    IO &IO, COFF::AuxiliarybfAndefSymbol &AAS) {
+  IO.mapRequired("Linenumber", AAS.Linenumber);
+  IO.mapRequired("PointerToNextFunction", AAS.PointerToNextFunction);
+}
+
+void MappingTraits<COFF::AuxiliaryWeakExternal>::mapping(
+    IO &IO, COFF::AuxiliaryWeakExternal &AWE) {
+  MappingNormalization<NWeakExternalCharacteristics, uint32_t> NWEC(
+      IO, AWE.Characteristics);
+  IO.mapRequired("TagIndex", AWE.TagIndex);
+  IO.mapRequired("Characteristics", NWEC->Characteristics);
+}
+
+void MappingTraits<COFF::AuxiliarySectionDefinition>::mapping(
+    IO &IO, COFF::AuxiliarySectionDefinition &ASD) {
+  MappingNormalization<NSectionSelectionType, uint8_t> NSST(
+      IO, ASD.Selection);
+
+  IO.mapRequired("Length", ASD.Length);
+  IO.mapRequired("NumberOfRelocations", ASD.NumberOfRelocations);
+  IO.mapRequired("NumberOfLinenumbers", ASD.NumberOfLinenumbers);
+  IO.mapRequired("CheckSum", ASD.CheckSum);
+  IO.mapRequired("Number", ASD.Number);
+  IO.mapOptional("Selection", NSST->SelectionType, COFFYAML::COMDATType(0));
+}
+
+void MappingTraits<COFF::AuxiliaryCLRToken>::mapping(
+    IO &IO, COFF::AuxiliaryCLRToken &ACT) {
+  MappingNormalization<NAuxTokenType, uint8_t> NATT(IO, ACT.AuxType);
+  IO.mapRequired("AuxType", NATT->AuxType);
+  IO.mapRequired("SymbolTableIndex", ACT.SymbolTableIndex);
+}
+
 void MappingTraits<COFFYAML::Symbol>::mapping(IO &IO, COFFYAML::Symbol &S) {
   MappingNormalization<NStorageClass, uint8_t> NS(IO, S.Header.StorageClass);
 
@@ -256,9 +350,12 @@ void MappingTraits<COFFYAML::Symbol>::mapping(IO &IO, COFFYAML::Symbol &S) {
   IO.mapRequired("SimpleType", S.SimpleType);
   IO.mapRequired("ComplexType", S.ComplexType);
   IO.mapRequired("StorageClass", NS->StorageClass);
-  IO.mapOptional("NumberOfAuxSymbols", S.Header.NumberOfAuxSymbols,
-                 (uint8_t) 0);
-  IO.mapOptional("AuxiliaryData", S.AuxiliaryData, object::yaml::BinaryRef());
+  IO.mapOptional("FunctionDefinition", S.FunctionDefinition);
+  IO.mapOptional("bfAndefSymbol", S.bfAndefSymbol);
+  IO.mapOptional("WeakExternal", S.WeakExternal);
+  IO.mapOptional("File", S.File, StringRef());
+  IO.mapOptional("SectionDefinition", S.SectionDefinition);
+  IO.mapOptional("CLRToken", S.CLRToken);
 }
 
 void MappingTraits<COFFYAML::Section>::mapping(IO &IO, COFFYAML::Section &Sec) {
diff --git a/test/Object/Inputs/COFF/i386.yaml b/test/Object/Inputs/COFF/i386.yaml
index 1badad8d59..7873df0a7e 100644
--- a/test/Object/Inputs/COFF/i386.yaml
+++ b/test/Object/Inputs/COFF/i386.yaml
@@ -39,8 +39,12 @@ symbols:
     SimpleType: IMAGE_SYM_TYPE_NULL # (0)
     ComplexType: IMAGE_SYM_DTYPE_NULL # (0)
     StorageClass: IMAGE_SYM_CLASS_STATIC # (3)
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:  !hex "240000000300000000000000010000000000" # |$.................|
+    SectionDefinition:
+      Length:          36
+      NumberOfRelocations: 3
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
 
   - !Symbol
     Name: .data
@@ -49,8 +53,12 @@ symbols:
     SimpleType: IMAGE_SYM_TYPE_NULL # (0)
     ComplexType: IMAGE_SYM_DTYPE_NULL # (0)
     StorageClass: IMAGE_SYM_CLASS_STATIC # (3)
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:  !hex "0D0000000000000000000000020000000000" # |..................|
+    SectionDefinition:
+      Length:          13
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
 
   - !Symbol
     Name: _main
diff --git a/test/Object/Inputs/COFF/x86-64.yaml b/test/Object/Inputs/COFF/x86-64.yaml
index b775ae9cdf..1dc2b10cf4 100644
--- a/test/Object/Inputs/COFF/x86-64.yaml
+++ b/test/Object/Inputs/COFF/x86-64.yaml
@@ -38,8 +38,12 @@ symbols:
     SimpleType: IMAGE_SYM_TYPE_NULL # (0)
     ComplexType: IMAGE_SYM_DTYPE_NULL # (0)
     StorageClass: IMAGE_SYM_CLASS_STATIC # (3)
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:  !hex "260000000300000000000000010000000000" # |&.................|
+    SectionDefinition:
+      Length:          38
+      NumberOfRelocations: 3
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          1
 
   - !Symbol
     Name: .data
@@ -48,8 +52,12 @@ symbols:
     SimpleType: IMAGE_SYM_TYPE_NULL # (0)
     ComplexType: IMAGE_SYM_DTYPE_NULL # (0)
     StorageClass: IMAGE_SYM_CLASS_STATIC # (3)
-    NumberOfAuxSymbols: 1
-    AuxiliaryData:  !hex "0D0000000000000000000000020000000000" # |..................|
+    SectionDefinition:
+      Length:          13
+      NumberOfRelocations: 0
+      NumberOfLinenumbers: 0
+      CheckSum:        0
+      Number:          2
 
   - !Symbol
     Name: main
diff --git a/test/Object/obj2yaml.test b/test/Object/obj2yaml.test
index 49541336c6..d96275fe2c 100644
--- a/test/Object/obj2yaml.test
+++ b/test/Object/obj2yaml.test
@@ -36,8 +36,12 @@ COFF-I386-NEXT:    SectionNumber: 1
 COFF-I386-NEXT:    SimpleType: IMAGE_SYM_TYPE_NULL
 COFF-I386-NEXT:    ComplexType: IMAGE_SYM_DTYPE_NULL
 COFF-I386-NEXT:    StorageClass: IMAGE_SYM_CLASS_STATIC
-COFF-I386-NEXT:    NumberOfAuxSymbols: 1
-COFF-I386-NEXT:    AuxiliaryData: 240000000300000000000000010000000000
+COFF-I386-NEXT:    SectionDefinition:
+COFF-I386-NEXT:      Length:          36
+COFF-I386-NEXT:      NumberOfRelocations: 3
+COFF-I386-NEXT:      NumberOfLinenumbers: 0
+COFF-I386-NEXT:      CheckSum:        0
+COFF-I386-NEXT:      Number:          1
 
 COFF-I386:       - Name: .data
 COFF-I386-NEXT:    Value: 0
@@ -45,8 +49,12 @@ COFF-I386-NEXT:    SectionNumber: 2
 COFF-I386-NEXT:    SimpleType: IMAGE_SYM_TYPE_NULL
 COFF-I386-NEXT:    ComplexType: IMAGE_SYM_DTYPE_NULL
 COFF-I386-NEXT:    StorageClass: IMAGE_SYM_CLASS_STATIC
-COFF-I386-NEXT:    NumberOfAuxSymbols: 1
-COFF-I386-NEXT:    AuxiliaryData: 0D0000000000000000000000020000000000
+COFF-I386-NEXT:    SectionDefinition:
+COFF-I386-NEXT:      Length:          13
+COFF-I386-NEXT:      NumberOfRelocations: 0
+COFF-I386-NEXT:      NumberOfLinenumbers: 0
+COFF-I386-NEXT:      CheckSum:        0
+COFF-I386-NEXT:      Number:          2
 
 COFF-I386:       - Name: _main
 COFF-I386-NEXT:    Value: 0
@@ -111,8 +119,12 @@ COFF-X86-64-NEXT:     SectionNumber: 1
 COFF-X86-64-NEXT:     SimpleType: IMAGE_SYM_TYPE_NULL
 COFF-X86-64-NEXT:     ComplexType: IMAGE_SYM_DTYPE_NULL
 COFF-X86-64-NEXT:     StorageClass: IMAGE_SYM_CLASS_STATIC
-COFF-X86-64-NEXT:     NumberOfAuxSymbols: 1
-COFF-X86-64-NEXT:     AuxiliaryData: 260000000300000000000000010000000000
+COFF-X86-64-NEXT:    SectionDefinition:
+COFF-X86-64-NEXT:      Length:          38
+COFF-X86-64-NEXT:      NumberOfRelocations: 3
+COFF-X86-64-NEXT:      NumberOfLinenumbers: 0
+COFF-X86-64-NEXT:      CheckSum:        0
+COFF-X86-64-NEXT:      Number:          1
 
 COFF-X86-64:        - Name: .data
 COFF-X86-64-NEXT:     Value: 0
@@ -120,8 +132,12 @@ COFF-X86-64-NEXT:     SectionNumber: 2
 COFF-X86-64-NEXT:     SimpleType: IMAGE_SYM_TYPE_NULL
 COFF-X86-64-NEXT:     ComplexType: IMAGE_SYM_DTYPE_NULL
 COFF-X86-64-NEXT:     StorageClass: IMAGE_SYM_CLASS_STATIC
-COFF-X86-64-NEXT:     NumberOfAuxSymbols: 1
-COFF-X86-64-NEXT:     AuxiliaryData: 0D0000000000000000000000020000000000
+COFF-X86-64-NEXT:    SectionDefinition:
+COFF-X86-64-NEXT:      Length:          13
+COFF-X86-64-NEXT:      NumberOfRelocations: 0
+COFF-X86-64-NEXT:      NumberOfLinenumbers: 0
+COFF-X86-64-NEXT:      CheckSum:        0
+COFF-X86-64-NEXT:      Number:          2
 
 COFF-X86-64:        - Name: main
 COFF-X86-64-NEXT:     Value: 0
diff --git a/tools/llvm-nm/llvm-nm.cpp b/tools/llvm-nm/llvm-nm.cpp
index 100a1f20a1..22e019a8a5 100644
--- a/tools/llvm-nm/llvm-nm.cpp
+++ b/tools/llvm-nm/llvm-nm.cpp
@@ -344,8 +344,7 @@ static char getSymbolNMTypeChar(COFFObjectFile &Obj, symbol_iterator I) {
       return 'i';
 
     // Check for section symbol.
-    else if (Symb->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC &&
-             Symb->Value == 0)
+    else if (Symb->isSectionDefinition())
       return 's';
   }
 
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index 3f871471bc..f5328a959e 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -663,8 +663,7 @@ static void PrintCOFFSymbolTable(const COFFObjectFile *coff) {
   for (int i = 0, e = header->NumberOfSymbols; i != e; ++i) {
     if (aux_count--) {
       // Figure out which type of aux this is.
-      if (symbol->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC
-          && symbol->Value == 0) { // Section definition.
+      if (symbol->isSectionDefinition()) { // Section definition.
         const coff_aux_section_definition *asd;
         if (error(coff->getAuxSymbol<coff_aux_section_definition>(i, asd)))
           return;
diff --git a/tools/llvm-readobj/COFFDumper.cpp b/tools/llvm-readobj/COFFDumper.cpp
index d2275f0aab..cd40da7d6c 100644
--- a/tools/llvm-readobj/COFFDumper.cpp
+++ b/tools/llvm-readobj/COFFDumper.cpp
@@ -946,12 +946,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
   W.printNumber("AuxSymbolCount", Symbol->NumberOfAuxSymbols);
 
   for (unsigned I = 0; I < Symbol->NumberOfAuxSymbols; ++I) {
-    if (Symbol->StorageClass     == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
-        Symbol->getBaseType()    == COFF::IMAGE_SYM_TYPE_NULL &&
-        Symbol->getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION &&
-        Symbol->SectionNumber != COFF::IMAGE_SYM_DEBUG &&
-        Symbol->SectionNumber != COFF::IMAGE_SYM_ABSOLUTE &&
-        Symbol->SectionNumber != COFF::IMAGE_SYM_UNDEFINED) {
+    if (Symbol->isFunctionDefinition()) {
       const coff_aux_function_definition *Aux;
       if (error(getSymbolAuxData(Obj, Symbol + I, Aux)))
         break;
@@ -963,11 +958,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
       W.printHex("PointerToNextFunction", Aux->PointerToNextFunction);
       W.printBinary("Unused", makeArrayRef(Aux->Unused));
 
-    } else if (
-        Symbol->StorageClass   == COFF::IMAGE_SYM_CLASS_WEAK_EXTERNAL ||
-        (Symbol->StorageClass  == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
-         Symbol->SectionNumber == COFF::IMAGE_SYM_UNDEFINED &&
-         Symbol->Value         == 0)) {
+    } else if (Symbol->isWeakExternal()) {
       const coff_aux_weak_external *Aux;
       if (error(getSymbolAuxData(Obj, Symbol + I, Aux)))
         break;
@@ -987,7 +978,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
                     makeArrayRef(WeakExternalCharacteristics));
       W.printBinary("Unused", makeArrayRef(Aux->Unused));
 
-    } else if (Symbol->StorageClass == COFF::IMAGE_SYM_CLASS_FILE) {
+    } else if (Symbol->isFileRecord()) {
       const coff_aux_file_record *Aux;
       if (error(getSymbolAuxData(Obj, Symbol + I, Aux)))
         break;
@@ -995,11 +986,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
       DictScope AS(W, "AuxFileRecord");
       W.printString("FileName", StringRef(Aux->FileName));
 
-    // C++/CLI creates external ABS symbols for non-const appdomain globals.
-    // These are also followed by an auxiliary section definition.
-    } else if (Symbol->StorageClass == COFF::IMAGE_SYM_CLASS_STATIC ||
-               (Symbol->StorageClass == COFF::IMAGE_SYM_CLASS_EXTERNAL &&
-                Symbol->SectionNumber == COFF::IMAGE_SYM_ABSOLUTE)) {
+    } else if (Symbol->isSectionDefinition()) {
       const coff_aux_section_definition *Aux;
       if (error(getSymbolAuxData(Obj, Symbol + I, Aux)))
         break;
@@ -1026,7 +1013,7 @@ void COFFDumper::printSymbol(const SymbolRef &Sym) {
 
         W.printNumber("AssocSection", AssocName, Aux->Number);
       }
-    } else if (Symbol->StorageClass == COFF::IMAGE_SYM_CLASS_CLR_TOKEN) {
+    } else if (Symbol->isCLRToken()) {
       const coff_aux_clr_token *Aux;
       if (error(getSymbolAuxData(Obj, Symbol + I, Aux)))
         break;
diff --git a/tools/obj2yaml/coff2yaml.cpp b/tools/obj2yaml/coff2yaml.cpp
index 6cf79aeabc..b003029407 100644
--- a/tools/obj2yaml/coff2yaml.cpp
+++ b/tools/obj2yaml/coff2yaml.cpp
@@ -78,6 +78,61 @@ void COFFDumper::dumpSections(unsigned NumSections) {
   }
 }
 
+static void
+dumpFunctionDefinition(COFFYAML::Symbol *Sym,
+                       const object::coff_aux_function_definition *ObjFD) {
+  COFF::AuxiliaryFunctionDefinition YAMLFD;
+  YAMLFD.TagIndex = ObjFD->TagIndex;
+  YAMLFD.TotalSize = ObjFD->TotalSize;
+  YAMLFD.PointerToLinenumber = ObjFD->PointerToLinenumber;
+  YAMLFD.PointerToNextFunction = ObjFD->PointerToNextFunction;
+
+  Sym->FunctionDefinition = YAMLFD;
+}
+
+static void
+dumpbfAndEfLineInfo(COFFYAML::Symbol *Sym,
+                    const object::coff_aux_bf_and_ef_symbol *ObjBES) {
+  COFF::AuxiliarybfAndefSymbol YAMLAAS;
+  YAMLAAS.Linenumber = ObjBES->Linenumber;
+  YAMLAAS.PointerToNextFunction = ObjBES->PointerToNextFunction;
+
+  Sym->bfAndefSymbol = YAMLAAS;
+}
+
+static void dumpWeakExternal(COFFYAML::Symbol *Sym,
+                             const object::coff_aux_weak_external *ObjWE) {
+  COFF::AuxiliaryWeakExternal YAMLWE;
+  YAMLWE.TagIndex = ObjWE->TagIndex;
+  YAMLWE.Characteristics = ObjWE->Characteristics;
+
+  Sym->WeakExternal = YAMLWE;
+}
+
+static void
+dumpSectionDefinition(COFFYAML::Symbol *Sym,
+                      const object::coff_aux_section_definition *ObjSD) {
+  COFF::AuxiliarySectionDefinition YAMLASD;
+  YAMLASD.Length = ObjSD->Length;
+  YAMLASD.NumberOfRelocations = ObjSD->NumberOfRelocations;
+  YAMLASD.NumberOfLinenumbers = ObjSD->NumberOfLinenumbers;
+  YAMLASD.CheckSum = ObjSD->CheckSum;
+  YAMLASD.Number = ObjSD->Number;
+  YAMLASD.Selection = ObjSD->Selection;
+
+  Sym->SectionDefinition = YAMLASD;
+}
+
+static void
+dumpCLRTokenDefinition(COFFYAML::Symbol *Sym,
+                       const object::coff_aux_clr_token *ObjCLRToken) {
+  COFF::AuxiliaryCLRToken YAMLCLRToken;
+  YAMLCLRToken.AuxType = ObjCLRToken->AuxType;
+  YAMLCLRToken.SymbolTableIndex = ObjCLRToken->SymbolTableIndex;
+
+  Sym->CLRToken = YAMLCLRToken;
+}
+
 void COFFDumper::dumpSymbols(unsigned NumSymbols) {
   std::vector<COFFYAML::Symbol> &Symbols = YAMLObj.Symbols;
   for (const auto &S : Obj.symbols()) {
@@ -90,7 +145,62 @@ void COFFDumper::dumpSymbols(unsigned NumSymbols) {
     Sym.Header.Value = Symbol->Value;
     Sym.Header.SectionNumber = Symbol->SectionNumber;
     Sym.Header.NumberOfAuxSymbols = Symbol->NumberOfAuxSymbols;
-    Sym.AuxiliaryData = object::yaml::BinaryRef(Obj.getSymbolAuxData(Symbol));
+
+    if (Symbol->NumberOfAuxSymbols > 0) {
+      ArrayRef<uint8_t> AuxData = Obj.getSymbolAuxData(Symbol);
+      if (Symbol->isFunctionDefinition()) {
+        // This symbol represents a function definition.
+        assert(Symbol->NumberOfAuxSymbols == 1 &&
+               "Expected a single aux symbol to describe this function!");
+
+        const object::coff_aux_function_definition *ObjFD =
+            reinterpret_cast<const object::coff_aux_function_definition *>(
+                AuxData.data());
+        dumpFunctionDefinition(&Sym, ObjFD);
+      } else if (Symbol->StorageClass == COFF::IMAGE_SYM_CLASS_FUNCTION) {
+        // This symbol describes function line number information.
+        assert(Symbol->NumberOfAuxSymbols == 1 &&
+               "Exepected a single aux symbol to describe this section!");
+
+        const object::coff_aux_bf_and_ef_symbol *ObjBES =
+            reinterpret_cast<const object::coff_aux_bf_and_ef_symbol *>(
+                AuxData.data());
+        dumpbfAndEfLineInfo(&Sym, ObjBES);
+      } else if (Symbol->isWeakExternal()) {
+        // This symbol represents a weak external definition.
+        assert(Symbol->NumberOfAuxSymbols == 1 &&
+               "Exepected a single aux symbol to describe this section!");
+
+        const object::coff_aux_weak_external *ObjWE =
+            reinterpret_cast<const object::coff_aux_weak_external *>(
+                AuxData.data());
+        dumpWeakExternal(&Sym, ObjWE);
+      } else if (Symbol->isFileRecord()) {
+        // This symbol represents a file record.
+        Sym.File = StringRef(reinterpret_cast<const char *>(AuxData.data()),
+                             Symbol->NumberOfAuxSymbols * COFF::SymbolSize);
+      } else if (Symbol->isSectionDefinition()) {
+        // This symbol represents a section definition.
+        assert(Symbol->NumberOfAuxSymbols == 1 &&
+               "Expected a single aux symbol to describe this section!");
+
+        const object::coff_aux_section_definition *ObjSD =
+            reinterpret_cast<const object::coff_aux_section_definition *>(
+                AuxData.data());
+        dumpSectionDefinition(&Sym, ObjSD);
+      } else if (Symbol->isCLRToken()) {
+        // This symbol represents a CLR token definition.
+        assert(Symbol->NumberOfAuxSymbols == 1 &&
+               "Expected a single aux symbol to describe this CLR Token");
+
+        const object::coff_aux_clr_token *ObjCLRToken =
+            reinterpret_cast<const object::coff_aux_clr_token *>(
+                AuxData.data());
+        dumpCLRTokenDefinition(&Sym, ObjCLRToken);
+      } else {
+        llvm_unreachable("Unhandled auxiliary symbol!");
+      }
+    }
     Symbols.push_back(Sym);
   }
 }
diff --git a/tools/yaml2obj/yaml2coff.cpp b/tools/yaml2obj/yaml2coff.cpp
index c757eb64fb..a0ede246bd 100644
--- a/tools/yaml2obj/yaml2coff.cpp
+++ b/tools/yaml2obj/yaml2coff.cpp
@@ -14,6 +14,7 @@
 
 #include "yaml2obj.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringSwitch.h"
@@ -153,13 +154,22 @@ static bool layoutCOFF(COFFParser &CP) {
   for (std::vector<COFFYAML::Symbol>::iterator i = CP.Obj.Symbols.begin(),
                                                e = CP.Obj.Symbols.end();
                                                i != e; ++i) {
-    unsigned AuxBytes = i->AuxiliaryData.binary_size();
-    if (AuxBytes % COFF::SymbolSize != 0) {
-      errs() << "AuxiliaryData size not a multiple of symbol size!\n";
-      return false;
-    }
-    i->Header.NumberOfAuxSymbols = AuxBytes / COFF::SymbolSize;
-    NumberOfSymbols += 1 + i->Header.NumberOfAuxSymbols;
+    uint32_t NumberOfAuxSymbols = 0;
+    if (i->FunctionDefinition)
+      NumberOfAuxSymbols += 1;
+    if (i->bfAndefSymbol)
+      NumberOfAuxSymbols += 1;
+    if (i->WeakExternal)
+      NumberOfAuxSymbols += 1;
+    if (!i->File.empty())
+      NumberOfAuxSymbols +=
+          (i->File.size() + COFF::SymbolSize - 1) / COFF::SymbolSize;
+    if (i->SectionDefinition)
+      NumberOfAuxSymbols += 1;
+    if (i->CLRToken)
+      NumberOfAuxSymbols += 1;
+    i->Header.NumberOfAuxSymbols = NumberOfAuxSymbols;
+    NumberOfSymbols += 1 + NumberOfAuxSymbols;
   }
 
   // Store all the allocated start addresses in the header.
@@ -194,6 +204,24 @@ binary_le_impl<value_type> binary_le(value_type V) {
   return binary_le_impl<value_type>(V);
 }
 
+template <size_t NumBytes>
+struct zeros_impl {
+  zeros_impl() {}
+};
+
+template <size_t NumBytes>
+raw_ostream &operator<<(raw_ostream &OS, const zeros_impl<NumBytes> &) {
+  char Buffer[NumBytes];
+  memset(Buffer, 0, sizeof(Buffer));
+  OS.write(Buffer, sizeof(Buffer));
+  return OS;
+}
+
+template <typename T>
+zeros_impl<sizeof(T)> zeros(const T &) {
+  return zeros_impl<sizeof(T)>();
+}
+
 bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
   OS << binary_le(CP.Obj.Header.Machine)
      << binary_le(CP.Obj.Header.NumberOfSections)
@@ -253,7 +281,45 @@ bool writeCOFF(COFFParser &CP, raw_ostream &OS) {
        << binary_le(i->Header.Type)
        << binary_le(i->Header.StorageClass)
        << binary_le(i->Header.NumberOfAuxSymbols);
-    i->AuxiliaryData.writeAsBinary(OS);
+
+    if (i->FunctionDefinition)
+      OS << binary_le(i->FunctionDefinition->TagIndex)
+         << binary_le(i->FunctionDefinition->TotalSize)
+         << binary_le(i->FunctionDefinition->PointerToLinenumber)
+         << binary_le(i->FunctionDefinition->PointerToNextFunction)
+         << zeros(i->FunctionDefinition->unused);
+    if (i->bfAndefSymbol)
+      OS << zeros(i->bfAndefSymbol->unused1)
+         << binary_le(i->bfAndefSymbol->Linenumber)
+         << zeros(i->bfAndefSymbol->unused2)
+         << binary_le(i->bfAndefSymbol->PointerToNextFunction)
+         << zeros(i->bfAndefSymbol->unused3);
+    if (i->WeakExternal)
+      OS << binary_le(i->WeakExternal->TagIndex)
+         << binary_le(i->WeakExternal->Characteristics)
+         << zeros(i->WeakExternal->unused);
+    if (!i->File.empty()) {
+      uint32_t NumberOfAuxRecords =
+          (i->File.size() + COFF::SymbolSize - 1) / COFF::SymbolSize;
+      uint32_t NumberOfAuxBytes = NumberOfAuxRecords * COFF::SymbolSize;
+      uint32_t NumZeros = NumberOfAuxBytes - i->File.size();
+      OS.write(i->File.data(), i->File.size());
+      for (uint32_t Padding = 0; Padding < NumZeros; ++Padding)
+        OS.write(0);
+    }
+    if (i->SectionDefinition)
+      OS << binary_le(i->SectionDefinition->Length)
+         << binary_le(i->SectionDefinition->NumberOfRelocations)
+         << binary_le(i->SectionDefinition->NumberOfLinenumbers)
+         << binary_le(i->SectionDefinition->CheckSum)
+         << binary_le(i->SectionDefinition->Number)
+         << binary_le(i->SectionDefinition->Selection)
+         << zeros(i->SectionDefinition->unused);
+    if (i->CLRToken)
+      OS << binary_le(i->CLRToken->AuxType)
+         << zeros(i->CLRToken->unused1)
+         << binary_le(i->CLRToken->SymbolTableIndex)
+         << zeros(i->CLRToken->unused2);
   }
 
   // Output string table.