Revert "[core] support .gnu.linkonce sections"

This reverts commit 5d5ca72a7876c3dd3dd1db83dc6a0d74be9e2cd1.

Discuss on a better design to raise error when there is a similar group with Gnu
linkonce sections and COMDAT sections.

llvm-svn: 205224

11 files changed, 11 insertions, 597 deletions

diff --git a/lld/include/lld/Core/DefinedAtom.h b/lld/include/lld/Core/DefinedAtom.h
index b911d2323b1..de325ada4b8 100644
--- a/lld/include/lld/Core/DefinedAtom.h
+++ b/lld/include/lld/Core/DefinedAtom.h
@@ -147,7 +147,6 @@ public:
     typeRWNote,             // Identifies readwrite note sections [ELF]
     typeNoAlloc,            // Identifies non allocatable sections [ELF]
     typeGroupComdat,        // Identifies a section group [ELF, COFF]
-    typeGnuLinkOnce,        // Identifies a gnu.linkonce section [ELF]
   };
 
   // Permission bits for atoms and segments. The order of these values are
diff --git a/lld/include/lld/Core/Resolver.h b/lld/include/lld/Core/Resolver.h
index b6d8185b3cd..006ed6e0e79 100644
--- a/lld/include/lld/Core/Resolver.h
+++ b/lld/include/lld/Core/Resolver.h
@@ -67,8 +67,8 @@ public:
 private:
   typedef std::function<void(StringRef, bool)> UndefCallback;
 
-  /// \brief Add section group/.gnu.linkonce if it does not exist previously.
-  bool maybeAddSectionGroupOrGnuLinkOnce(const DefinedAtom &atom);
+  /// \brief Add section group if it does not exist previously.
+  void maybeAddSectionGroup(const DefinedAtom &atom);
 
   /// \brief The main function that iterates over the files to resolve
   bool resolveUndefines();
diff --git a/lld/lib/Core/DefinedAtom.cpp b/lld/lib/Core/DefinedAtom.cpp
index 806bd6f4521..8362aadb21c 100644
--- a/lld/lib/Core/DefinedAtom.cpp
+++ b/lld/lib/Core/DefinedAtom.cpp
@@ -72,7 +72,6 @@ DefinedAtom::ContentPermissions DefinedAtom::permissions(ContentType type) {
     return permRW_L;
 
   case typeGroupComdat:
-  case typeGnuLinkOnce:
   case typeUnknown:
   case typeTempLTO:
     return permUnknown;
diff --git a/lld/lib/Core/Resolver.cpp b/lld/lib/Core/Resolver.cpp
index 6ff898726b3..9555fef22ba 100644
--- a/lld/lib/Core/Resolver.cpp
+++ b/lld/lib/Core/Resolver.cpp
@@ -184,22 +184,11 @@ void Resolver::doUndefinedAtom(const UndefinedAtom &atom) {
 }
 
 /// \brief Add the section group and the group-child reference members.
-bool Resolver::maybeAddSectionGroupOrGnuLinkOnce(const DefinedAtom &atom) {
+void Resolver::maybeAddSectionGroup(const DefinedAtom &atom) {
   // First time adding a group ?
   bool isFirstTime = _symbolTable.addGroup(atom);
-
-  if (!isFirstTime) {
-    // If duplicate symbols are allowed, select the first group.
-    if (_context.getAllowDuplicates())
-      return true;
-    const DefinedAtom *prevGroup = llvm::dyn_cast<DefinedAtom>(_symbolTable.findGroup(atom.name()));
-    assert(prevGroup && "Internal Error: The group atom could only be a defined atom");
-    // The atoms should be of the same content type, reject invalid group
-    // resolution behaviors.
-    if (atom.contentType() != prevGroup->contentType())
-      return false;
-    return true;
-  }
+  if (!isFirstTime)
+    return;
 
   for (const Reference *r : atom) {
     if ((r->kindNamespace() == lld::Reference::KindNamespace::all) &&
@@ -211,7 +200,6 @@ bool Resolver::maybeAddSectionGroupOrGnuLinkOnce(const DefinedAtom &atom) {
       _symbolTable.add(*target);
     }
   }
-  return true;
 }
 
 // called on each atom when a file is added
@@ -241,14 +229,8 @@ void Resolver::doDefinedAtom(const DefinedAtom &atom) {
   // add to list of known atoms
   _atoms.push_back(&atom);
 
-  if ((atom.contentType() == DefinedAtom::typeGroupComdat) ||
-      (atom.contentType() == DefinedAtom::typeGnuLinkOnce)) {
-    // Raise error if there exists a similar gnu linkonce section.
-    if (!maybeAddSectionGroupOrGnuLinkOnce(atom)) {
-      llvm::errs() << "SymbolTable: error while merging " << atom.name() << "\n";
-      llvm::report_fatal_error("duplicate symbol error");
-    }
-  }
+  if (atom.contentType() == DefinedAtom::typeGroupComdat)
+    maybeAddSectionGroup(atom);
   else
     _symbolTable.add(atom);
 
diff --git a/lld/lib/ReaderWriter/Native/WriterNative.cpp b/lld/lib/ReaderWriter/Native/WriterNative.cpp
index c1173380faa..9735783b0a9 100644
--- a/lld/lib/ReaderWriter/Native/WriterNative.cpp
+++ b/lld/lib/ReaderWriter/Native/WriterNative.cpp
@@ -41,8 +41,7 @@ public:
       // We are trying to process all atoms, but the defined() iterator does not
       // return group children. So, when a group parent is found, we need to
       // handle each child atom.
-      if (defAtom->contentType() == DefinedAtom::typeGroupComdat ||
-          defAtom->contentType() == DefinedAtom::typeGnuLinkOnce) {
+      if (defAtom->contentType() == DefinedAtom::typeGroupComdat) {
         for (const Reference *r : *defAtom) {
           if (r->kindNamespace() != lld::Reference::KindNamespace::all)
             continue;
diff --git a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
index b2295f87d66..49de7f551cf 100644
--- a/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
+++ b/lld/lib/ReaderWriter/YAML/ReaderWriterYAML.cpp
@@ -71,9 +71,7 @@ public:
       if (!atom->name().empty())
         buildDuplicateNameMap(*atom);
 
-      if (atom->contentType() == DefinedAtom::typeGroupComdat ||
-          atom->contentType() == DefinedAtom::typeGnuLinkOnce) {
-
+      if (atom->contentType() == DefinedAtom::typeGroupComdat) {
         for (const lld::Reference *ref : *atom) {
           if (ref->kindNamespace() != lld::Reference::KindNamespace::all)
             continue;
@@ -231,8 +229,7 @@ private:
     }
 
     if (const lld::DefinedAtom *da = dyn_cast<DefinedAtom>(atom)) {
-      if (da->contentType() == DefinedAtom::typeGroupComdat ||
-          da->contentType() == DefinedAtom::typeGnuLinkOnce) {
+      if (da->contentType() == DefinedAtom::typeGroupComdat) {
         if (_groupMap.count(name)) {
           _io.setError(Twine("duplicate group name: ") + name);
         } else {
@@ -479,8 +476,7 @@ template <> struct ScalarEnumerationTraits<lld::DefinedAtom::ContentType> {
     io.enumCase(value, "ro-note",         DefinedAtom::typeRONote);
     io.enumCase(value, "rw-note",         DefinedAtom::typeRWNote);
     io.enumCase(value, "no-alloc",        DefinedAtom::typeNoAlloc);
-    io.enumCase(value, "group-comdat",    DefinedAtom::typeGroupComdat);
-    io.enumCase(value, "gnu-linkonce",    DefinedAtom::typeGnuLinkOnce);
+    io.enumCase(value, "group-comdat", DefinedAtom::typeGroupComdat);
   }
 };
 
diff --git a/lld/test/core/gnulinkonce-rearrange-resolve.objtxt b/lld/test/core/gnulinkonce-rearrange-resolve.objtxt
deleted file mode 100644
index dbcc95591a9..00000000000
--- a/lld/test/core/gnulinkonce-rearrange-resolve.objtxt
+++ /dev/null
@@ -1,115 +0,0 @@
-# RUN: lld -core %s | FileCheck %s
-
-#
-# Test that gnu linkonce sections are parsed and the first section selected for symbol
-# resolution
-#
-
----
-defined-atoms:
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
----
-defined-atoms:
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-...
-
-# CHECK: defined-atoms:
-# CHECK:   - name:            g1
-# CHECK:     ref-name:        [[PARENT:[a-zA-Z\.0-9_]+]]
-# CHECK:     type:            gnu-linkonce
-# CHECK:     references:
-# CHECK:       - kind:            group-child
-# CHECK:         target:          f1
-# CHECK:       - kind:            group-child
-# CHECK:         target:          f2
-# CHECK:       - kind:            group-child
-# CHECK:         target:          [[CHILD:[a-zA-Z\.0-9_]+]]
-# CHECK:       - kind:            group-child
-# CHECK:         target:          d1
-# CHECK:   - name:            f1
-# CHECK:     references:
-# CHECK:       - kind:            group-parent
-# CHECK:         target:          [[PARENT]]
-# CHECK:   - name:            f2
-# CHECK:     references:
-# CHECK:       - kind:            group-parent
-# CHECK:         target:          [[PARENT]]
-# CHECK:   - name:            g1
-# CHECK:     ref-name:        [[CHILD]]
-# CHECK:     references:
-# CHECK:       - kind:            group-parent
-# CHECK:         target:          [[PARENT]]
-# CHECK:   - name:            d1
-# CHECK:     references:
-# CHECK:       - kind:            group-parent
-# CHECK:         target:          [[PARENT]]
diff --git a/lld/test/core/gnulinkonce-remaining-undef.objtxt b/lld/test/core/gnulinkonce-remaining-undef.objtxt
deleted file mode 100644
index ee5f681ac02..00000000000
--- a/lld/test/core/gnulinkonce-remaining-undef.objtxt
+++ /dev/null
@@ -1,113 +0,0 @@
-# RUN: lld -core %s | FileCheck %s
-
-#
-# Test that gnu linkonce sections are parsed and the first section selected for
-# symbol resolution. The second file which has the same gnu linkonce section has
-# a unresolved undefined symbol. lets make sure that the symbol is kept around
-# in the final link and remains undefined.
-#
-
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
----
-defined-atoms:
-  - name:            anotherfunction
-    scope:           global
-    type:            data
-    references:
-      - kind:            layout-before
-        target:          f3
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f3
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          f3
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
-undefined-atoms:
-    - name:              f3
-      can-be-null:       never
-...
-
-#CHECK:   - name:            anotherfunction
-#CHECK:     scope:           global
-#CHECK:     type:            data
-#CHECK:     references:
-#CHECK:       - kind:            layout-before
-#CHECK:         offset:          0
-#CHECK:         target:          f3
-#CHECK: undefined-atoms:
-#CHECK:   - name:            f3
diff --git a/lld/test/core/gnulinkonce-resolve.objtxt b/lld/test/core/gnulinkonce-resolve.objtxt
deleted file mode 100644
index ff099a5ba9d..00000000000
--- a/lld/test/core/gnulinkonce-resolve.objtxt
+++ /dev/null
@@ -1,133 +0,0 @@
-# RUN: lld -core %s | FileCheck %s
-
-#
-# Test that gnu linkonce sections are parsed and the first section selected for symbol
-# resolution
-#
-
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
-...
-
-#CHECK: defined-atoms:
-#CHECK:   - name:            g1
-#CHECK:     ref-name:        [[PARENT:[a-zA-Z\.0-9_]+]]
-#CHECK:     scope:           global
-#CHECK:     type:            gnu-linkonce
-#CHECK:     references:
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDONE:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDTWO:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDTHREE:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDFOUR:[a-zA-Z\.0-9_]+]]
-#CHECK:   - name:            f1
-#CHECK:     ref-name:        [[GCHILDONE]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            f2
-#CHECK:     ref-name:        [[GCHILDTWO]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            g1
-#CHECK:     ref-name:        [[GCHILDTHREE]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            d1
-#CHECK:     ref-name:        [[GCHILDFOUR]]
-#CHECK:     scope:           global
-#CHECK:     type:            data
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK: ...
diff --git a/lld/test/core/gnulinkonce-simple.objtxt b/lld/test/core/gnulinkonce-simple.objtxt
deleted file mode 100644
index 1a96b62669b..00000000000
--- a/lld/test/core/gnulinkonce-simple.objtxt
+++ /dev/null
@@ -1,112 +0,0 @@
-# RUN: lld -core %s | FileCheck %s
-
-#
-# Test that gnu linkonce sections are parsed properly when there is a reference to a
-# atom from outside the gnu linkonce section.
-#
-
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          d1
-      - kind:            group-child
-        target:          g1
-  - name:            anotherfunction
-    scope:           global
-    type:            data
-    references:
-      - kind:            layout-before
-        target:          f1
-
-undefined-atoms:
-    - name:              f1
-      can-be-null:       never
-...
-
-#CHECK: defined-atoms:
-#CHECK:   - name:            g1
-#CHECK:     ref-name:        [[PARENT:[a-zA-Z\.0-9_]+]]
-#CHECK:     scope:           global
-#CHECK:     type:            gnu-linkonce
-#CHECK:     references:
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDONE:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDTWO:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDTHREE:[a-zA-Z\.0-9_]+]]
-#CHECK:       - kind:            group-child
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDFOUR:[a-zA-Z\.0-9_]+]]
-#CHECK:   - name:            f1
-#CHECK:     ref-name:        [[GCHILDONE]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            f2
-#CHECK:     ref-name:        [[GCHILDTWO]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            d1
-#CHECK:     ref-name:        [[GCHILDTHREE]]
-#CHECK:     scope:           global
-#CHECK:     type:            data
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            g1
-#CHECK:     ref-name:        [[GCHILDFOUR]]
-#CHECK:     scope:           global
-#CHECK:     references:
-#CHECK:       - kind:            group-parent
-#CHECK:         offset:          0
-#CHECK:         target:          [[PARENT]]
-#CHECK:   - name:            anotherfunction
-#CHECK:     scope:           global
-#CHECK:     type:            data
-#CHECK:     references:
-#CHECK:       - kind:            layout-before
-#CHECK:         offset:          0
-#CHECK:         target:          [[GCHILDONE]]
-#CHECK: ...
diff --git a/lld/test/core/sectiongroup-gnulinkonce-error.objtxt b/lld/test/core/sectiongroup-gnulinkonce-error.objtxt
deleted file mode 100644
index e54cdfe0571..00000000000
--- a/lld/test/core/sectiongroup-gnulinkonce-error.objtxt
+++ /dev/null
@@ -1,88 +0,0 @@
-# RUN: not lld -core %s 2>&1 | FileCheck %s
-
-#
-# Test that section groups/gnu linkonce sections are parsed and a merge error 
-# is displayed at the time of symbol resolution.
-#
-
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            group-comdat
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
----
-defined-atoms:
-  - name:            f1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            f2
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            code
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            d1
-    scope:           global
-    type:            data
-    references:
-      - kind:            group-parent
-        target:          g1
-  - name:            g1
-    scope:           global
-    type:            gnu-linkonce
-    references:
-      - kind:            group-child
-        target:          f1
-      - kind:            group-child
-        target:          f2
-      - kind:            group-child
-        target:          g1
-      - kind:            group-child
-        target:          d1
-...
-
-#CHECK: SymbolTable: error while merging g1
-#CHECK: LLVM ERROR: duplicate symbol error
-