ICF

Makefile

@@ -11,7 +11,8 @@ LDFLAGS=-L$(TBB_LIBDIR) -Wl,-rpath=$(TBB_LIBDIR) \
         -L$(MALLOC_LIBDIR) -Wl,-rpath=$(MALLOC_LIBDIR)
 LIBS=-lcrypto -pthread -ltbb -lmimalloc
 OBJS=main.o object_file.o input_sections.o output_chunks.o mapfile.o perf.o \
-     linker_script.o archive_file.o output_file.o subprocess.o gc_sections.o
+     linker_script.o archive_file.o output_file.o subprocess.o gc_sections.o \
+     icf.o
 
 mold: $(OBJS)
 	$(CXX) $(CFLAGS) $(OBJS) -o $@ $(LDFLAGS) $(LIBS)

main.cc

@@ -940,6 +940,10 @@ static Config parse_nonpositional_args(std::span<std::string_view> args,
       conf.print_gc_sections = true;
     } else if (read_flag(args, "no-print-gc-sections")) {
       conf.print_gc_sections = false;
+    } else if (read_flag(args, "icf")) {
+      conf.icf = true;
+    } else if (read_flag(args, "no-icf")) {
+      conf.icf = false;
     } else if (read_flag(args, "quick-exit")) {
       conf.quick_exit = true;
     } else if (read_flag(args, "no-quick-exit")) {
@@ -1194,6 +1198,10 @@ int main(int argc, char **argv) {
   if (config.gc_sections)
     gc_sections();
 
+  // Merge identical read-only sections.
+  if (config.icf)
+    icf_sections();
+
   // Merge string constants in SHF_MERGE sections.
   handle_mergeable_strings();
 

mold.h

@@ -1073,6 +1073,12 @@ private:
 
 void gc_sections();
 
+//
+// icf_sections.cc
+//
+
+void icf_sections();
+
 //
 // icf.cc
 //