Compile-time tuning: assembly phase
Not as much compile-time gain from reworking the assembly phase as I'd
hoped, but still worthwhile. Should see ~2% improvement thanks to
the assembly rework. On the other hand, expect some huge gains for some
application thanks to better detection of large machine-generated init
methods. Thinkfree shows a 25% improvement.
The major assembly change was to establish thread the LIR nodes that
require fixup into a fixup chain. Only those are processed during the
final assembly pass(es). This doesn't help for methods which only
require a single pass to assemble, but does speed up the larger methods
which required multiple assembly passes.
Also replaced the block_map_ basic block lookup table (which contained
space for a BasicBlock* for each dex instruction unit) with a block id
map - cutting its space requirements by half in a 32-bit pointer
environment.
Changes:
o Reduce size of LIR struct by 12.5% (one of the big memory users)
o Repurpose the use/def portion of the LIR after optimization complete.
o Encode instruction bits to LIR
o Thread LIR nodes requiring pc fixup
o Change follow-on assembly passes to only consider fixup LIRs
o Switch on pc-rel fixup kind
o Fast-path for small methods - single pass assembly
o Avoid using cb[n]z for null checks (almost always exceed displacement)
o Improve detection of large initialization methods.
o Rework def/use flag setup.
o Remove a sequential search from FindBlock using lookup table of 16-bit
block ids rather than full block pointers.
o Eliminate pcRelFixup and use fixup kind instead.
o Add check for 16-bit overflow on dex offset.
Change-Id: I4c6615f83fed46f84629ad6cfe4237205a9562b4
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index fefcab9..2952570 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -117,6 +117,11 @@
#endif
) {
VLOG(compiler) << "Compiling " << PrettyMethod(method_idx, dex_file) << "...";
+ if (code_item->insns_size_in_code_units_ >= 0x10000) {
+ LOG(INFO) << "Method size exceeds compiler limits: " << code_item->insns_size_in_code_units_
+ << " in " << PrettyMethod(method_idx, dex_file);
+ return NULL;
+ }
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
CompilationUnit cu(&compiler.GetArenaPool());
@@ -151,7 +156,7 @@
*/
if (compiler_backend == kPortable) {
- // Fused long branches not currently usseful in bitcode.
+ // Fused long branches not currently useful in bitcode.
cu.disable_opt |= (1 << kBranchFusing);
}