(optionally) run BranchPrefixHoisting

Reviewed By: ssj933

Differential Revision: D66525536

fbshipit-source-id: 3077eb8eaf0805344b1898d4afec89adb3dfb633

libredex/ConfigFiles.cpp

@@ -517,6 +517,8 @@ void ConfigFiles::load_inliner_config(inliner::InlinerConfig* inliner_config) {
   jw.get("run_reg_alloc", false, shrinker_config.run_reg_alloc);
   jw.get("run_fast_reg_alloc", false, shrinker_config.run_fast_reg_alloc);
   jw.get("run_dedup_blocks", false, shrinker_config.run_dedup_blocks);
+  jw.get("run_branch_prefix_hoisting", false,
+         shrinker_config.run_branch_prefix_hoisting);
   jw.get("debug", false, inliner_config->debug);
   jw.get("blocklist", {}, inliner_config->blocklist);
   jw.get("caller_blocklist", {}, inliner_config->caller_blocklist);

libredex/GlobalConfig.cpp

@@ -28,6 +28,8 @@ void InlinerConfig::bind_config() {
   bind("run_cse", shrinker.run_cse, shrinker.run_cse);
   bind("run_dedup_blocks", shrinker.run_dedup_blocks,
        shrinker.run_dedup_blocks);
+  bind("run_branch_prefix_hoisting", shrinker.run_branch_prefix_hoisting,
+       shrinker.run_branch_prefix_hoisting);
   bind("run_copy_prop", shrinker.run_copy_prop, shrinker.run_copy_prop);
   bind("run_reg_alloc", shrinker.run_reg_alloc, shrinker.run_reg_alloc);
   bind("run_fast_reg_alloc", shrinker.run_fast_reg_alloc,

libredex/ShrinkerConfig.h

@@ -22,6 +22,7 @@ struct ShrinkerConfig {
   bool run_reg_alloc{false};
   bool run_fast_reg_alloc{false};
   bool run_dedup_blocks{false};
+  bool run_branch_prefix_hoisting{false};
 
   bool normalize_new_instances{true};
 

opt/shrinker/ShrinkerPass.cpp

@@ -28,6 +28,8 @@ void ShrinkerPass::bind_config() {
        "Whether to run fast register allocation.");
   bind("run_dedup_blocks", true, m_config.run_dedup_blocks,
        "Whether to run dedup-blocks.");
+  bind("run_branch_prefix_hoisting", true, m_config.run_branch_prefix_hoisting,
+       "Whether to run branch-prefix hoisting.");
 
   bind("compute_pure_methods", true, m_config.compute_pure_methods,
        "Whether to compute pure methods with a relatively expensive analysis "
@@ -87,6 +89,8 @@ void ShrinkerPass::run_pass(DexStoresVector& stores,
                   shrinker.get_dedup_blocks_stats().insns_removed);
   mgr.incr_metric("blocks_eliminated_by_dedup_blocks",
                   shrinker.get_dedup_blocks_stats().blocks_removed);
+  mgr.incr_metric("instructions_eliminated_branch_prefix_hoisting",
+                  shrinker.get_branch_prefix_hoisting_stats());
   mgr.incr_metric("methods_reg_alloced", shrinker.get_methods_reg_alloced());
   mgr.incr_metric("localdce_init_class_instructions_added",
                   shrinker.get_local_dce_stats().init_class_instructions_added);
@@ -110,6 +114,8 @@ void ShrinkerPass::run_pass(DexStoresVector& stores,
                    shrinker.get_local_dce_seconds());
   Timer::add_timer("Shrinker.Shrinking.DedupBlocks",
                    shrinker.get_dedup_blocks_seconds());
+  Timer::add_timer("Shrinker.Shrinking.BranchPrefixHoisting",
+                   shrinker.get_branch_prefix_hoisting_seconds());
   Timer::add_timer("Shrinker.Shrinking.RegAlloc",
                    shrinker.get_reg_alloc_seconds());
 }

service/method-inliner/MethodInliner.cpp

@@ -1102,6 +1102,8 @@ void run_inliner(
                   inliner.get_info().unreachable_insns);
   mgr.incr_metric("instructions_eliminated_dedup_blocks",
                   shrinker.get_dedup_blocks_stats().insns_removed);
+  mgr.incr_metric("instructions_eliminated_branch_prefix_hoisting",
+                  shrinker.get_branch_prefix_hoisting_stats());
   mgr.incr_metric("blocks_eliminated_by_dedup_blocks",
                   shrinker.get_dedup_blocks_stats().blocks_removed);
   mgr.incr_metric("methods_reg_alloced", shrinker.get_methods_reg_alloced());
@@ -1128,6 +1130,8 @@ void run_inliner(
                    shrinker.get_local_dce_seconds());
   Timer::add_timer("Inliner.Shrinking.DedupBlocks",
                    shrinker.get_dedup_blocks_seconds());
+  Timer::add_timer("Inliner.Shrinking.BranchPrefixHoisting",
+                   shrinker.get_branch_prefix_hoisting_seconds());
   Timer::add_timer("Inliner.Shrinking.RegAlloc",
                    shrinker.get_reg_alloc_seconds());
   Timer::add_timer("Inliner.Inlining.inline_callees",

service/shrinker/Shrinker.cpp

@@ -9,6 +9,8 @@
 
 #include <fstream>
 
+#include "BranchPrefixHoisting.h"
+#include "ConstantUses.h"
 #include "ConstructorParams.h"
 #include "LinearScan.h"
 #include "RandomForest.h"
@@ -86,7 +88,7 @@ Shrinker::Shrinker(
       m_enabled(config.run_const_prop || config.run_cse ||
                 config.run_copy_prop || config.run_local_dce ||
                 config.run_reg_alloc || config.run_fast_reg_alloc ||
-                config.run_dedup_blocks),
+                config.run_dedup_blocks || config.run_branch_prefix_hoisting),
       m_init_classes_with_side_effects(init_classes_with_side_effects),
       m_pure_methods(configured_pure_methods),
       m_finalish_field_names(configured_finalish_field_names),
@@ -218,6 +220,7 @@ void Shrinker::shrink_code(
   copy_propagation_impl::Stats copy_prop_stats;
   LocalDce::Stats local_dce_stats;
   dedup_blocks_impl::Stats dedup_blocks_stats;
+  size_t branch_prefix_hoisting_stats{0};
 
   code->build_cfg();
   if (m_config.run_const_prop) {
@@ -312,6 +315,19 @@ void Shrinker::shrink_code(
     dedup_blocks_stats = dedup_blocks.get_stats();
   }
 
+  if (m_config.run_branch_prefix_hoisting) {
+    auto timer = m_branch_prefix_hoisting_timer.scope();
+    auto& cfg = code->cfg();
+    Lazy<const constant_uses::ConstantUses> constant_uses([&] {
+      return std::make_unique<const constant_uses::ConstantUses>(
+          cfg, is_static, declaring_type, proto->get_rtype(), proto->get_args(),
+          method_describer,
+          /* force_type_inference */ true);
+    });
+    branch_prefix_hoisting_stats = branch_prefix_hoisting_impl::process_cfg(
+        cfg, constant_uses, /* can_allocate_regs */ true);
+  }
+
   auto data_after_dedup = get_features(kMMINLDataCollectionLevel);
   if (traceEnabled(MMINL, kMMINLDataCollectionLevel)) {
     TRACE(
@@ -331,6 +347,7 @@ void Shrinker::shrink_code(
   m_dedup_blocks_stats += dedup_blocks_stats;
   m_methods_shrunk++;
   m_methods_reg_alloced += reg_alloc_inc;
+  m_branch_prefix_hoisting_stats += branch_prefix_hoisting_stats;
 }
 
 void Shrinker::log_metrics(ScopedMetrics& sm) const {

service/shrinker/Shrinker.h

@@ -82,6 +82,9 @@ class Shrinker {
   const dedup_blocks_impl::Stats& get_dedup_blocks_stats() const {
     return m_dedup_blocks_stats;
   }
+  size_t get_branch_prefix_hoisting_stats() const {
+    return m_branch_prefix_hoisting_stats;
+  }
   size_t get_methods_shrunk() const { return m_methods_shrunk; }
   size_t get_methods_reg_alloced() const { return m_methods_reg_alloced; }
 
@@ -104,6 +107,9 @@ class Shrinker {
   double get_local_dce_seconds() const {
     return m_local_dce_timer.get_seconds();
   }
+  double get_branch_prefix_hoisting_seconds() const {
+    return m_branch_prefix_hoisting_timer.get_seconds();
+  }
   double get_dedup_blocks_seconds() const {
     return m_dedup_blocks_timer.get_seconds();
   }
@@ -167,6 +173,8 @@ class Shrinker {
   copy_propagation_impl::Stats m_copy_prop_stats;
   AccumulatingTimer m_local_dce_timer;
   LocalDce::Stats m_local_dce_stats;
+  AccumulatingTimer m_branch_prefix_hoisting_timer;
+  size_t m_branch_prefix_hoisting_stats{0};
   AccumulatingTimer m_dedup_blocks_timer;
   dedup_blocks_impl::Stats m_dedup_blocks_stats;
   AccumulatingTimer m_reg_alloc_timer;