[mach-o] Add support for using export tries
On Darwin at runtime, dyld will prefer to use the export trie of a dylib instead
of the traditional symbol table (which is large and requires a binary search).
This change enables the linker to generate an export trie and to prefer it if
found in a dylib being linked against. This also simples the yaml for dylibs
because the yaml form of the trie can be reduced to just a sequence of names.
llvm-svn: 217066
diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
index cf0a9cf..3bc05c3 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
@@ -109,6 +109,7 @@
std::error_code addSymbols(const lld::File &atomFile, NormalizedFile &file);
void addIndirectSymbols(const lld::File &atomFile, NormalizedFile &file);
void addRebaseAndBindingInfo(const lld::File &, NormalizedFile &file);
+ void addExportInfo(const lld::File &, NormalizedFile &file);
void addSectionRelocs(const lld::File &, NormalizedFile &file);
void buildDataInCodeArray(const lld::File &, NormalizedFile &file);
void addDependentDylibs(const lld::File &, NormalizedFile &file);
@@ -1085,6 +1086,35 @@
}
}
+
+void Util::addExportInfo(const lld::File &atomFile, NormalizedFile &nFile) {
+ if (_context.outputMachOType() == llvm::MachO::MH_OBJECT)
+ return;
+
+ for (SectionInfo *sect : _sectionInfos) {
+ for (const AtomInfo &info : sect->atomsAndOffsets) {
+ const DefinedAtom *atom = info.atom;
+ if (atom->scope() != Atom::scopeGlobal)
+ continue;
+ if (_context.exportRestrictMode()) {
+ if (!_context.exportSymbolNamed(atom->name()))
+ continue;
+ }
+ Export exprt;
+ exprt.name = atom->name();
+ exprt.offset = _atomToAddress[atom]; // FIXME: subtract base address
+ exprt.kind = EXPORT_SYMBOL_FLAGS_KIND_REGULAR;
+ if (atom->merge() == DefinedAtom::mergeAsWeak)
+ exprt.flags = EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION;
+ else
+ exprt.flags = 0;
+ exprt.otherOffset = 0;
+ exprt.otherName = StringRef();
+ nFile.exportInfo.push_back(exprt);
+ }
+ }
+}
+
uint32_t Util::fileFlags() {
// FIXME: these need to determined at runtime.
if (_context.outputMachOType() == MH_OBJECT) {
@@ -1128,6 +1158,7 @@
}
util.addIndirectSymbols(atomFile, normFile);
util.addRebaseAndBindingInfo(atomFile, normFile);
+ util.addExportInfo(atomFile, normFile);
util.addSectionRelocs(atomFile, normFile);
util.buildDataInCodeArray(atomFile, normFile);
util.copyEntryPointAddress(normFile);