Add option to configure a multiplier for different kinds of unused args

Summary: The default is always a multiplier of 1, so this is a behavior-preserving change.

Reviewed By: beicy

Differential Revision: D57005516

fbshipit-source-id: f67421702b647d7aa5c28009c4fc126a2226ce8c

opt/methodinline/MethodInlinePass.cpp

@@ -66,6 +66,39 @@ void MethodInlinePass::bind_config() {
   bind("cross_dex_penalty_const",
        DEFAULT_COST_CONFIG.cross_dex_penalty_const,
        m_inliner_cost_config.cross_dex_penalty_const);
+  bind("unused_arg_zero_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_zero_multiplier,
+       m_inliner_cost_config.unused_arg_zero_multiplier);
+  bind("unused_arg_non_zero_constant_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_non_zero_constant_multiplier,
+       m_inliner_cost_config.unused_arg_non_zero_constant_multiplier);
+  bind("unused_arg_nez_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_nez_multiplier,
+       m_inliner_cost_config.unused_arg_nez_multiplier);
+  bind("unused_arg_interval_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_interval_multiplier,
+       m_inliner_cost_config.unused_arg_interval_multiplier);
+  bind("unused_arg_singleton_object_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_singleton_object_multiplier,
+       m_inliner_cost_config.unused_arg_singleton_object_multiplier);
+  bind("unused_arg_object_with_immutable_attr_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_object_with_immutable_attr_multiplier,
+       m_inliner_cost_config.unused_arg_object_with_immutable_attr_multiplier);
+  bind("unused_arg_string_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_string_multiplier,
+       m_inliner_cost_config.unused_arg_string_multiplier);
+  bind("unused_arg_class_object_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_class_object_multiplier,
+       m_inliner_cost_config.unused_arg_class_object_multiplier);
+  bind("unused_arg_new_object_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_new_object_multiplier,
+       m_inliner_cost_config.unused_arg_new_object_multiplier);
+  bind("unused_arg_other_object_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_other_object_multiplier,
+       m_inliner_cost_config.unused_arg_other_object_multiplier);
+  bind("unused_arg_not_top_multiplier",
+       DEFAULT_COST_CONFIG.unused_arg_not_top_multiplier,
+       m_inliner_cost_config.unused_arg_not_top_multiplier);
 }
 
 void MethodInlinePass::run_pass(DexStoresVector& stores,

service/method-inliner/Inliner.cpp

@@ -1369,11 +1369,21 @@ InlinedCost MultiMethodInliner::get_inlined_cost(
       /* ignore_unreachable */ !reduced_code,
       [&](auto* insn) { return opcode::is_a_load_param(insn->opcode()); });
   auto def_use_chains = chains.get_def_use_chains();
+  size_t arg_idx = 0;
   for (auto& mie : cfg->get_param_instructions()) {
-    auto uses = def_use_chains[mie.insn];
-    if (uses.empty()) {
-      unused_args++;
+    auto it = def_use_chains.find(mie.insn);
+    if (it == def_use_chains.end() || it->second.empty()) {
+      float multiplier =
+          1.0f; // all other multipliers are relative to this normative value
+      if (call_site_summary) {
+        const auto& cv = call_site_summary->arguments.get(arg_idx);
+        if (!cv.is_top()) {
+          multiplier = get_unused_arg_multiplier(cv);
+        }
+      }
+      unused_args += multiplier;
     }
+    arg_idx++;
   }
   insn_size = cfg->estimate_code_units();
   if (returns > 1) {
@@ -1396,6 +1406,44 @@ InlinedCost MultiMethodInliner::get_inlined_cost(
                        insn_size};
 }
 
+float MultiMethodInliner::get_unused_arg_multiplier(
+    const ConstantValue& cv) const {
+  always_assert(!cv.is_top());
+  always_assert(!cv.is_bottom());
+  if (cv.is_zero()) {
+    return m_inliner_cost_config.unused_arg_zero_multiplier;
+  }
+  if (auto scd = cv.maybe_get<SignedConstantDomain>()) {
+    if (scd->get_constant()) {
+      return m_inliner_cost_config.unused_arg_non_zero_constant_multiplier;
+    }
+    if (scd->is_nez()) {
+      return m_inliner_cost_config.unused_arg_nez_multiplier;
+    }
+    return m_inliner_cost_config.unused_arg_interval_multiplier;
+  }
+  if (cv.is_object()) {
+    if (cv.is_singleton_object()) {
+      return m_inliner_cost_config.unused_arg_singleton_object_multiplier;
+    }
+    if (cv.is_object_with_immutable_attr()) {
+      return m_inliner_cost_config
+          .unused_arg_object_with_immutable_attr_multiplier;
+    }
+    if (cv.maybe_get<StringDomain>()) {
+      return m_inliner_cost_config.unused_arg_string_multiplier;
+    }
+    if (cv.maybe_get<ConstantClassObjectDomain>()) {
+      return m_inliner_cost_config.unused_arg_class_object_multiplier;
+    }
+    if (cv.maybe_get<NewObjectDomain>()) {
+      return m_inliner_cost_config.unused_arg_new_object_multiplier;
+    }
+    return m_inliner_cost_config.unused_arg_other_object_multiplier;
+  }
+  return m_inliner_cost_config.unused_arg_not_top_multiplier;
+}
+
 const InlinedCost* MultiMethodInliner::get_fully_inlined_cost(
     const DexMethod* callee) {
   return m_fully_inlined_costs

service/method-inliner/Inliner.h

@@ -87,6 +87,18 @@ struct InlinerCostConfig {
   size_t cross_dex_penalty_coe1;
   size_t cross_dex_penalty_coe2;
   size_t cross_dex_penalty_const;
+
+  float unused_arg_zero_multiplier;
+  float unused_arg_non_zero_constant_multiplier;
+  float unused_arg_nez_multiplier;
+  float unused_arg_interval_multiplier;
+  float unused_arg_singleton_object_multiplier;
+  float unused_arg_object_with_immutable_attr_multiplier;
+  float unused_arg_string_multiplier;
+  float unused_arg_class_object_multiplier;
+  float unused_arg_new_object_multiplier;
+  float unused_arg_other_object_multiplier;
+  float unused_arg_not_top_multiplier;
 };
 
 const struct InlinerCostConfig DEFAULT_COST_CONFIG = {
@@ -108,6 +120,17 @@ const struct InlinerCostConfig DEFAULT_COST_CONFIG = {
     1, // cross_dex_penalty_coe1;
     0, // cross_dex_penalty_coe2;
     1, // cross_dex_penalty_const;
+    1.0f, // unused_arg_zero_multiplier
+    1.0f, // unused_arg_non_zero_constant_multiplier
+    1.0f, // unused_arg_nez_multiplier
+    1.0f, // unused_arg_interval_multiplier
+    1.0f, // unused_arg_singleton_object_multiplier
+    1.0f, // unused_arg_object_with_immutable_attr_multiplier
+    1.0f, // unused_arg_string_multiplier
+    1.0f, // unused_arg_class_object_multiplier
+    1.0f, // unused_arg_new_object_multiplier
+    1.0f, // unused_arg_other_object_multiplier
+    1.0f, // unused_arg_not_top_multiplier
 };
 
 // All call-sites of a callee.
@@ -474,6 +497,8 @@ class MultiMethodInliner {
       const IRCode* code,
       const CallSiteSummary* call_site_summary = nullptr);
 
+  float get_unused_arg_multiplier(const ConstantValue&) const;
+
   /**
    * Estimate inlined cost for fully inlining a callee without using any
    * summaries for pruning.