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/compiler_enums.h b/compiler/dex/compiler_enums.h
index 97a682f..17b5bb5 100644
--- a/compiler/dex/compiler_enums.h
+++ b/compiler/dex/compiler_enums.h
@@ -412,6 +412,27 @@
std::ostream& operator<<(std::ostream& os, const OatBitMapKind& kind);
+// LIR fixup kinds for Arm
+enum FixupKind {
+ kFixupNone,
+ kFixupLabel, // For labels we just adjust the offset.
+ kFixupLoad, // Mostly for imediates.
+ kFixupVLoad, // FP load which *may* be pc-relative.
+ kFixupCBxZ, // Cbz, Cbnz.
+ kFixupPushPop, // Not really pc relative, but changes size based on args.
+ kFixupCondBranch, // Conditional branch
+ kFixupT1Branch, // Thumb1 Unconditional branch
+ kFixupT2Branch, // Thumb2 Unconditional branch
+ kFixupBlx1, // Blx1 (start of Blx1/Blx2 pair).
+ kFixupBl1, // Bl1 (start of Bl1/Bl2 pair).
+ kFixupAdr, // Adr.
+ kFixupMovImmLST, // kThumb2MovImm16LST.
+ kFixupMovImmHST, // kThumb2MovImm16HST.
+ kFixupAlign4, // Align to 4-byte boundary.
+};
+
+std::ostream& operator<<(std::ostream& os, const FixupKind& kind);
+
} // namespace art
#endif // ART_COMPILER_DEX_COMPILER_ENUMS_H_