do lto before dce, since lto opens up dce opportunities

kripken · kripken · commit 98fda6ea8171 · 2012-12-21T10:47:40.000-08:00
diff --git a/emcc b/emcc
@@ -1055,19 +1055,21 @@ try:
       if DEBUG: save_intermediate('opt', 'bc')
       # Do LTO in a separate pass to work around LLVM bug XXX (see failure e.g. in cubescript)
     if shared.Building.can_build_standalone():
+      # If we can LTO, do it before dce, since it opens up dce opportunities
+      if llvm_lto and shared.Building.can_use_unsafe_opts():
+        if not shared.Building.can_inline(): link_opts.append('-disable-inlining')
+        link_opts += ['-std-link-opts', '-disable-internalize']
+        if DEBUG: print >> sys.stderr, 'emcc: LLVM linktime:', link_opts
+        shared.Building.llvm_opt(in_temp(target_basename + '.bc'), link_opts)
+        if DEBUG: save_intermediate('linktime', 'bc')
+        link_opts = []
       # At minimum remove dead functions etc., this potentially saves a lot in the size of the generated code (and the time to compile it)
       exports = ','.join(map(lambda exp: exp[1:], shared.Settings.EXPORTED_FUNCTIONS))
       # internalize carefully, llvm 3.2 will remove even main if not told not to
       link_opts += ['-internalize', '-internalize-public-api-list=' + exports, '-globaldce']
       if DEBUG: print >> sys.stderr, 'emcc: LLVM linktime:', link_opts
       shared.Building.llvm_opt(in_temp(target_basename + '.bc'), link_opts)
       if DEBUG: save_intermediate('dce', 'bc')
-      if llvm_lto and shared.Building.can_use_unsafe_opts():
-        if not shared.Building.can_inline(): link_opts.append('-disable-inlining')
-        link_opts = ['-std-link-opts', '-disable-internalize']
-        if DEBUG: print >> sys.stderr, 'emcc: LLVM linktime:', link_opts
-        shared.Building.llvm_opt(in_temp(target_basename + '.bc'), link_opts)
-        if DEBUG: save_intermediate('linktime', 'bc')
 
   # Prepare .ll for Emscripten
   if not LEAVE_INPUTS_RAW:
