Add more merging/coalescing test cases and make core linking work for them

llvm-svn: 147130

3 files changed, 77 insertions, 21 deletions

diff --git a/lld/lib/Core/SymbolTable.cpp b/lld/lib/Core/SymbolTable.cpp
index ebd4c0bde50..223f15e6cda 100644
--- a/lld/lib/Core/SymbolTable.cpp
+++ b/lld/lib/Core/SymbolTable.cpp
@@ -24,6 +24,10 @@
 
 namespace lld {
 
+SymbolTable::SymbolTable(Platform& plat)
+  : _platform(plat) {
+}
+
 void SymbolTable::add(const Atom &atom) {
   assert(atom.scope() != Atom::scopeTranslationUnit);
   if ( !atom.internalName() ) {
@@ -39,6 +43,7 @@ enum NameCollisionResolution {
   NCR_Second,
   NCR_Weak,
   NCR_Larger,
+  NCR_Dup,
   NCR_Error
 };
 
@@ -46,7 +51,7 @@ static NameCollisionResolution cases[6][6] = {
   //regular     weak         tentative   absolute    undef      sharedLib
   {
     // first is regular
-    NCR_Error,  NCR_First,   NCR_First,  NCR_Error,  NCR_First, NCR_First
+    NCR_Dup,    NCR_First,   NCR_First,  NCR_Error,  NCR_First, NCR_First
   },
   {
     // first is weak
@@ -75,26 +80,44 @@ static NameCollisionResolution collide(Atom::Definition first,
   return cases[first][second];
 }
 
-void SymbolTable::addByName(const Atom &atom) {
-  llvm::StringRef name = atom.name();
+void SymbolTable::addByName(const Atom & newAtom) {
+  llvm::StringRef name = newAtom.name();
   const Atom *existing = this->findByName(name);
   if (existing == NULL) {
     // name is not in symbol table yet, add it associate with this atom
-    _nameTable[name] = &atom;
+    _nameTable[name] = &newAtom;
   } else {
     // name is already in symbol table and associated with another atom
-    switch (collide(existing->definition(), atom.definition())) {
+    switch (collide(existing->definition(), newAtom.definition())) {
     case NCR_First:
       // using first, just add new to _replacedAtoms
-      _replacedAtoms[&atom] = existing;
+      _replacedAtoms[&newAtom] = existing;
       break;
     case NCR_Second:
       // using second, update tables
-      _nameTable[name] = &atom;
-      _replacedAtoms[existing] = &atom;
+      _nameTable[name] = &newAtom;
+      _replacedAtoms[existing] = &newAtom;
+      break;
+    case NCR_Dup:
+      if ( existing->mergeDuplicates() && newAtom.mergeDuplicates() ) {
+          // using existing atom, add new atom to _replacedAtoms
+        _replacedAtoms[&newAtom] = existing;
+      }
+      else {
+        const Atom& use = _platform.handleMultipleDefinitions(*existing, newAtom);
+        if ( &use == existing ) {
+          // using existing atom, add new atom to _replacedAtoms
+          _replacedAtoms[&newAtom] = existing;
+        }
+        else {
+          // using new atom, update tables
+          _nameTable[name] = &newAtom;
+          _replacedAtoms[existing] = &newAtom;
+        }
+      }
       break;
     default:
-      llvm::report_fatal_error("unhandled switch clause");
+      llvm::report_fatal_error("SymbolTable::addByName(): unhandled switch clause");
     }
   }
 }
diff --git a/lld/lib/Core/YamlReader.cpp b/lld/lib/Core/YamlReader.cpp
index 6250939b8a7..c35664e0280 100644
--- a/lld/lib/Core/YamlReader.cpp
+++ b/lld/lib/Core/YamlReader.cpp
@@ -137,6 +137,8 @@ void YAML::parse(llvm::MemoryBuffer *mb, std::vector<const Entry *> &entries) {
         state = inTriplePeriod;
       } else if (c == '\n') {
         // ignore empty lines
+      } else if (c == '\t') {
+        llvm::report_fatal_error("TAB character found in yaml file");
       } else {
         return;
       }
@@ -244,13 +246,14 @@ public:
           , ContentType ct
           , SectionChoice sc
           , bool intn
+          , bool md
           , DeadStripKind dsk
           , bool tb
           , bool al
           , Alignment a
           , YAMLFile& f
           , const char *n)
-    : Atom(ord, d, s, ct, sc, intn, dsk, tb, al, a)
+    : Atom(ord, d, s, ct, sc, intn, md, dsk, tb, al, a)
     , _file(f)
     , _name(n)
     , _size(0)
@@ -311,6 +314,7 @@ public:
   void setType(const char *n);
   void setAlign2(const char *n);
   void setDefinition(const char *n);
+  void setMergeDuplicates(const char *n);
 
   void setFixupKind(const char *n);
   void setFixupOffset(const char *n);
@@ -328,7 +332,7 @@ private:
   Atom::Definition _def;
   Atom::SectionChoice _sectionChoice;
   bool _internalName;
-  bool _userVisibleName;
+  bool _mergeDuplicates;
   Atom::DeadStripKind _dontDeadStrip;
   bool _thumb;
   bool _alias;
@@ -341,7 +345,8 @@ YAMLAtomState::YAMLAtomState()
   , _align(0, 0)
   , _type(Atom::typeData)
   , _scope(Atom::scopeGlobal)
-  , _userVisibleName(true)
+  , _internalName(false)
+  , _mergeDuplicates(false)
   , _dontDeadStrip(Atom::deadStripNormal)
   , _thumb(false)
   , _alias(false) {
@@ -354,8 +359,8 @@ YAMLAtomState::YAMLAtomState()
 
 void YAMLAtomState::makeAtom(YAMLFile& f) {
   Atom *a = new YAMLAtom(_ordinal, _def, _scope, _type, _sectionChoice,
-                         _internalName, _dontDeadStrip, _thumb, _alias,
-                         _align, f, _name);
+                         _internalName, _mergeDuplicates, _dontDeadStrip, 
+                         _thumb, _alias, _align, f, _name);
 
   f._atoms.push_back(a);
   ++_ordinal;
@@ -369,6 +374,7 @@ void YAMLAtomState::makeAtom(YAMLFile& f) {
   _def              = Atom::definitionRegular;
   _sectionChoice    = Atom::sectionBasedOnContent;
   _internalName     = false;
+  _mergeDuplicates  = false;
   _dontDeadStrip    = Atom::deadStripNormal;
   _thumb            = false;
   _alias            = false;
@@ -419,12 +425,23 @@ void YAMLAtomState::setDefinition(const char *s) {
     _def = Atom::definitionRegular;
   else if (strcmp(s, "tentative") == 0)
     _def = Atom::definitionTentative;
+  else if (strcmp(s, "weak") == 0)
+    _def = Atom::definitionWeak;
   else if (strcmp(s, "absolute") == 0)
     _def = Atom::definitionAbsolute;
   else
     llvm::report_fatal_error("bad definition value");
 }
 
+void YAMLAtomState::setMergeDuplicates(const char *s) {
+  if (strcmp(s, "true") == 0)
+    _mergeDuplicates = true;
+  else if (strcmp(s, "false") == 0)
+    _mergeDuplicates = false;
+  else
+    llvm::report_fatal_error("bad merge-duplicates value");
+}
+
 void YAMLAtomState::setFixupKind(const char *s) {
   if (strcmp(s, "pcrel32") == 0)
     _ref.kind = 1;
@@ -525,6 +542,9 @@ llvm::error_code parseObjectText( llvm::MemoryBuffer *mb
         } else if (strcmp(entry->key, "definition") == 0) {
           atomState.setDefinition(entry->value);
           haveAtom = true;
+        } else if (strcmp(entry->key, "merge-duplicates") == 0) {
+          atomState.setMergeDuplicates(entry->value);
+          haveAtom = true;
         } else if (strcmp(entry->key, "fixups") == 0) {
           inFixups = true;
         }
diff --git a/lld/lib/Core/YamlWriter.cpp b/lld/lib/Core/YamlWriter.cpp
index 711fd1ac027..e5711068c7c 100644
--- a/lld/lib/Core/YamlWriter.cpp
+++ b/lld/lib/Core/YamlWriter.cpp
@@ -28,11 +28,22 @@ public:
 
   virtual void doFile(const class File &) { }
   virtual void doAtom(const class Atom &atom) {
-    _out << "    - name:        " << atom.name() << "\n";
-    _out << "      internal-name:" << atom.internalName() << "\n";
-    _out << "      definition:  " << definitionString(atom.definition()) <<"\n";
-    _out << "      scope:       " << scopeString(atom.scope()) << "\n";
-    _out << "      type:        " << typeString(atom.contentType()) << "\n";
+    _out << "    - name:             " << atom.name() << "\n";
+    
+    if ( atom.internalName() )
+      _out << "      internal-name:     true\n";
+      
+    if ( atom.definition() != Atom::definitionRegular )
+      _out << "      definition:       " << definitionString(atom.definition()) <<"\n";
+      
+    if ( atom.scope() != Atom::scopeTranslationUnit )
+      _out << "      scope:            " << scopeString(atom.scope()) << "\n";
+      
+    _out << "      type:             " << typeString(atom.contentType()) << "\n";
+    
+    if ( atom.mergeDuplicates() )
+      _out << "      merge-duplicates: true\n";
+      
     if (atom.referencesBegin() != atom.referencesEnd()) {
       _out << "      fixups:\n";
       for (Reference::iterator it = atom.referencesBegin(),
@@ -76,6 +87,8 @@ private:
     switch (def) {
     case Atom::definitionRegular:
       return "regular";
+    case Atom::definitionWeak:
+      return "weak";
     case Atom::definitionTentative:
       return "tentative";
     case Atom::definitionAbsolute:
@@ -88,11 +101,11 @@ private:
   llvm::raw_ostream &_out;
 };
 
-void writeObjectText(File *file, llvm::raw_ostream &out) {
+void writeObjectText(File &file, llvm::raw_ostream &out) {
   Handler h(out);
   out << "---\n";
   out << "atoms:\n";
-  file->forEachAtom(h);
+  file.forEachAtom(h);
   out << "...\n";
 }