Revert "[MC] Factor MCObjectStreamer::addFragmentAtoms out of MachO streamer."
This reverts rL331412. We didn't up using fragment atoms
in the wasm object writer after all.
Differential Revision: https://reviews.llvm.org/D48173
llvm-svn: 334734
diff --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 4b74c56..69995fa 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -459,7 +459,30 @@
// We have to set the fragment atom associations so we can relax properly for
// Mach-O.
- addFragmentAtoms();
+
+ // First, scan the symbol table to build a lookup table from fragments to
+ // defining symbols.
+ DenseMap<const MCFragment *, const MCSymbol *> DefiningSymbolMap;
+ for (const MCSymbol &Symbol : getAssembler().symbols()) {
+ if (getAssembler().isSymbolLinkerVisible(Symbol) && Symbol.isInSection() &&
+ !Symbol.isVariable()) {
+ // An atom defining symbol should never be internal to a fragment.
+ assert(Symbol.getOffset() == 0 &&
+ "Invalid offset in atom defining symbol!");
+ DefiningSymbolMap[Symbol.getFragment()] = &Symbol;
+ }
+ }
+
+ // Set the fragment atom associations by tracking the last seen atom defining
+ // symbol.
+ for (MCSection &Sec : getAssembler()) {
+ const MCSymbol *CurrentAtom = nullptr;
+ for (MCFragment &Frag : Sec) {
+ if (const MCSymbol *Symbol = DefiningSymbolMap.lookup(&Frag))
+ CurrentAtom = Symbol;
+ Frag.setAtom(CurrentAtom);
+ }
+ }
this->MCObjectStreamer::FinishImpl();
}