svn commit: r349971 - head/contrib/llvm/tools/lld/ELF

[Dimitry Andric]

Author: dim
Date: Sat Jul 13 15:04:30 2019
New Revision: 349971
URL: https://svnweb.freebsd.org/changeset/base/349971

Log:
  Pull in r365760 from upstream lld trunk (by Fangrui Song):
  
    [ELF] Handle non-glob patterns before glob patterns in version
    scripts & fix a corner case of --dynamic-list
  
    This fixes PR38549, which is silently accepted by ld.bfd.
    This seems correct because it makes sense to let non-glob patterns
    take precedence over glob patterns.
  
    lld issues an error because
    `assignWildcardVersion(ver, VER_NDX_LOCAL);` is processed before
    `assignExactVersion(ver, v.id, v.name);`.
  
    Move all assignWildcardVersion() calls after assignExactVersion()
    calls to fix this.
  
    Also, move handleDynamicList() to the bottom. computeBinding() called
    by includeInDynsym() has this cryptic rule:
  
        if (versionId == VER_NDX_LOCAL && isDefined() && !isPreemptible)
  	return STB_LOCAL;
  
    Before the change:
  
    * foo's version is set to VER_NDX_LOCAL due to `local: *`
    * handleDynamicList() is called
      - foo.computeBinding() is STB_LOCAL
      - foo.includeInDynsym() is false
      - foo.isPreemptible is not set (wrong)
    * foo's version is set to V1
  
    After the change:
  
    * foo's version is set to VER_NDX_LOCAL due to `local: *`
    * foo's version is set to V1
    * handleDynamicList() is called
      - foo.computeBinding() is STB_GLOBAL
      - foo.includeInDynsym() is true
      - foo.isPreemptible is set (correct)
  
    Reviewed By: ruiu
  
    Differential Revision: https://reviews.llvm.org/D64550
  
  This makes it longer necessary to patch the version scripts for the
  samba ports, to avoid "duplicate symbol 'pdb_search_init' in version
  script" errors.
  
  PR:		230602
  MFC after:	3 days

Modified:
  head/contrib/llvm/tools/lld/ELF/SymbolTable.cpp
  head/contrib/llvm/tools/lld/ELF/SymbolTable.h

Modified: head/contrib/llvm/tools/lld/ELF/SymbolTable.cpp
==============================================================================
--- head/contrib/llvm/tools/lld/ELF/SymbolTable.cpp	Sat Jul 13 14:42:09 2019	(r349970)
+++ head/contrib/llvm/tools/lld/ELF/SymbolTable.cpp	Sat Jul 13 15:04:30 2019	(r349971)
@@ -654,20 +654,6 @@ std::vector<Symbol *> SymbolTable::findAllByVersion(Sy
   return Res;
 }
 
-// If there's only one anonymous version definition in a version
-// script file, the script does not actually define any symbol version,
-// but just specifies symbols visibilities.
-void SymbolTable::handleAnonymousVersion() {
-  for (SymbolVersion &Ver : Config->VersionScriptGlobals)
-    assignExactVersion(Ver, VER_NDX_GLOBAL, "global");
-  for (SymbolVersion &Ver : Config->VersionScriptGlobals)
-    assignWildcardVersion(Ver, VER_NDX_GLOBAL);
-  for (SymbolVersion &Ver : Config->VersionScriptLocals)
-    assignExactVersion(Ver, VER_NDX_LOCAL, "local");
-  for (SymbolVersion &Ver : Config->VersionScriptLocals)
-    assignWildcardVersion(Ver, VER_NDX_LOCAL);
-}
-
 // Handles -dynamic-list.
 void SymbolTable::handleDynamicList() {
   for (SymbolVersion &Ver : Config->DynamicList) {
@@ -731,23 +717,27 @@ void SymbolTable::assignWildcardVersion(SymbolVersion 
 
 // This function processes version scripts by updating VersionId
 // member of symbols.
+// If there's only one anonymous version definition in a version
+// script file, the script does not actually define any symbol version,
+// but just specifies symbols visibilities.
 void SymbolTable::scanVersionScript() {
-  // Handle edge cases first.
-  handleAnonymousVersion();
-  handleDynamicList();
-
-  // Now we have version definitions, so we need to set version ids to symbols.
-  // Each version definition has a glob pattern, and all symbols that match
-  // with the pattern get that version.
-
   // First, we assign versions to exact matching symbols,
   // i.e. version definitions not containing any glob meta-characters.
+  for (SymbolVersion &Ver : Config->VersionScriptGlobals)
+    assignExactVersion(Ver, VER_NDX_GLOBAL, "global");
+  for (SymbolVersion &Ver : Config->VersionScriptLocals)
+    assignExactVersion(Ver, VER_NDX_LOCAL, "local");
   for (VersionDefinition &V : Config->VersionDefinitions)
     for (SymbolVersion &Ver : V.Globals)
       assignExactVersion(Ver, V.Id, V.Name);
 
   // Next, we assign versions to fuzzy matching symbols,
   // i.e. version definitions containing glob meta-characters.
+  for (SymbolVersion &Ver : Config->VersionScriptGlobals)
+    assignWildcardVersion(Ver, VER_NDX_GLOBAL);
+  for (SymbolVersion &Ver : Config->VersionScriptLocals)
+    assignWildcardVersion(Ver, VER_NDX_LOCAL);
+
   // Note that because the last match takes precedence over previous matches,
   // we iterate over the definitions in the reverse order.
   for (VersionDefinition &V : llvm::reverse(Config->VersionDefinitions))
@@ -759,6 +749,12 @@ void SymbolTable::scanVersionScript() {
   // Let them parse and update their names to exclude version suffix.
   for (Symbol *Sym : SymVector)
     Sym->parseSymbolVersion();
+
+  // isPreemptible is false at this point. To correctly compute the binding of a
+  // Defined (which is used by includeInDynsym()), we need to know if it is
+  // VER_NDX_LOCAL or not. If defaultSymbolVersion is VER_NDX_LOCAL, we should
+  // compute symbol versions before handling --dynamic-list.
+  handleDynamicList();
 }
 
 template void SymbolTable::addFile<ELF32LE>(InputFile *);

Modified: head/contrib/llvm/tools/lld/ELF/SymbolTable.h
==============================================================================
--- head/contrib/llvm/tools/lld/ELF/SymbolTable.h	Sat Jul 13 14:42:09 2019	(r349970)
+++ head/contrib/llvm/tools/lld/ELF/SymbolTable.h	Sat Jul 13 15:04:30 2019	(r349971)
@@ -90,7 +90,6 @@ class SymbolTable { (private)
   std::vector<Symbol *> findAllByVersion(SymbolVersion Ver);
 
   llvm::StringMap<std::vector<Symbol *>> &getDemangledSyms();
-  void handleAnonymousVersion();
   void assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
                           StringRef VersionName);
   void assignWildcardVersion(SymbolVersion Ver, uint16_t VersionId);