llvm-mc: Improve indirect symbol support (add the indirect index table).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80059 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 4b26574..fc5d31c 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -70,6 +70,13 @@
STF_PrivateExtern = 0x10
};
+ /// IndirectSymbolFlags - Flags for encoding special values in the indirect
+ /// symbol entry.
+ enum IndirectSymbolFlags {
+ ISF_Local = 0x80000000,
+ ISF_Absolute = 0x40000000
+ };
+
/// MachSymbolData - Helper struct for containing some precomputed information
/// on symbols.
struct MachSymbolData {
@@ -315,7 +322,8 @@
Write32(0); // FIXME: Value
}
- void BindIndirectSymbols(MCAssembler &Asm) {
+ void BindIndirectSymbols(MCAssembler &Asm,
+ DenseMap<MCSymbol*, MCSymbolData*> &SymbolMap) {
// This is the point where 'as' creates actual symbols for indirect symbols
// (in the following two passes). It would be easier for us to do this
// sooner when we see the attribute, but that makes getting the order in the
@@ -323,13 +331,6 @@
//
// FIXME: Revisit this when the dust settles.
- // FIXME: This should not be needed.
- DenseMap<MCSymbol*, MCSymbolData *> SymbolMap;
-
- for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
- ie = Asm.symbol_end(); it != ie; ++it)
- SymbolMap[&it->getSymbol()] = it;
-
// Bind non lazy symbol pointers first.
for (MCAssembler::indirect_symbol_iterator it = Asm.indirect_symbol_begin(),
ie = Asm.indirect_symbol_end(); it != ie; ++it) {
@@ -474,7 +475,16 @@
void WriteObject(MCAssembler &Asm) {
unsigned NumSections = Asm.size();
- BindIndirectSymbols(Asm);
+ // Compute the symbol -> symbol data map.
+ //
+ // FIXME: This should not be here.
+ DenseMap<MCSymbol*, MCSymbolData *> SymbolMap;
+ for (MCAssembler::symbol_iterator it = Asm.symbol_begin(),
+ ie = Asm.symbol_end(); it != ie; ++it)
+ SymbolMap[&it->getSymbol()] = it;
+
+ // Create symbol data for any indirect symbols.
+ BindIndirectSymbols(Asm, SymbolMap);
// Compute symbol table information.
SmallString<256> StringTable;
@@ -567,11 +577,47 @@
// Write the symbol table data, if used.
if (NumSymbols) {
+ // FIXME: We shouldn't need this index table.
+ DenseMap<MCSymbol*, unsigned> SymbolIndexMap;
+ for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) {
+ MCSymbol &Symbol = LocalSymbolData[i].SymbolData->getSymbol();
+ SymbolIndexMap.insert(std::make_pair(&Symbol, SymbolIndexMap.size()));
+ }
+ for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i) {
+ MCSymbol &Symbol = ExternalSymbolData[i].SymbolData->getSymbol();
+ SymbolIndexMap.insert(std::make_pair(&Symbol, SymbolIndexMap.size()));
+ }
+ for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i) {
+ MCSymbol &Symbol = UndefinedSymbolData[i].SymbolData->getSymbol();
+ SymbolIndexMap.insert(std::make_pair(&Symbol, SymbolIndexMap.size()));
+ }
+
// Write the indirect symbol entries.
//
// FIXME: We need the symbol index map for this.
- for (unsigned i = 0, e = Asm.indirect_symbol_size(); i != e; ++i)
- Write32(0);
+ for (MCAssembler::indirect_symbol_iterator
+ it = Asm.indirect_symbol_begin(),
+ ie = Asm.indirect_symbol_end(); it != ie; ++it) {
+ // Indirect symbols in the non lazy symbol pointer section have some
+ // special handling.
+ const MCSectionMachO &Section =
+ static_cast<const MCSectionMachO&>(it->SectionData->getSection());
+ unsigned Type =
+ Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
+ if (Type == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
+ // If this symbol is defined and internal, mark it as such.
+ if (it->Symbol->isDefined() &&
+ !SymbolMap.lookup(it->Symbol)->isExternal()) {
+ uint32_t Flags = ISF_Local;
+ if (it->Symbol->isAbsolute())
+ Flags |= ISF_Absolute;
+ Write32(Flags);
+ continue;
+ }
+ }
+
+ Write32(SymbolIndexMap[it->Symbol]);
+ }
// FIXME: Check that offsets match computed ones.