option to treat exception constructors as strict

Summary:
We also don't want to inline constructors of throwable (exception, error) classes, as they capture the current stack trace in a way that is sensitive to inlining.

This new behaviour is introduced via a new flag that is off by default. So this is in effect a behavior-preserving change.

TODO: Explore alternative approach that changes symbolication/positions.

Reviewed By: ssj933

Differential Revision: D63564560

fbshipit-source-id: f520533191c841ec0125b31a89c99e71fb4aa2e9

libredex/ConfigFiles.cpp

@@ -490,6 +490,8 @@ void ConfigFiles::load_inliner_config(inliner::InlinerConfig* inliner_config) {
   jw.get("virtual", true, inliner_config->virtual_inline);
   jw.get("true_virtual_inline", false, inliner_config->true_virtual_inline);
   jw.get("relaxed_init_inline", false, inliner_config->relaxed_init_inline);
+  jw.get("strict_throwable_init_inline", false,
+         inliner_config->strict_throwable_init_inline);
   jw.get("throws", false, inliner_config->throws_inline);
   jw.get("throw_after_no_return", false, inliner_config->throw_after_no_return);
   jw.get("max_cost_for_constant_propagation",

libredex/GlobalConfig.cpp

@@ -11,6 +11,8 @@ void InlinerConfig::bind_config() {
   bind("delete_non_virtuals", delete_non_virtuals, delete_non_virtuals);
   bind("true_virtual_inline", true_virtual_inline, true_virtual_inline);
   bind("relaxed_init_inline", relaxed_init_inline, relaxed_init_inline);
+  bind("strict_throwable_init_inline", strict_throwable_init_inline,
+       strict_throwable_init_inline);
   bind("intermediate_shrinking", intermediate_shrinking,
        intermediate_shrinking);
   bind("enforce_method_size_limit", enforce_method_size_limit,

libredex/InlinerConfig.h

@@ -25,6 +25,7 @@ struct InlinerConfig {
   bool virtual_inline{true};
   bool true_virtual_inline{false};
   bool relaxed_init_inline{false};
+  bool strict_throwable_init_inline{false};
   bool throws_inline{false};
   bool throw_after_no_return{false};
   bool enforce_method_size_limit{true};

service/method-inliner/Inliner.cpp

@@ -1680,11 +1680,19 @@ bool MultiMethodInliner::can_inline_init(const DexMethod* init_method) {
                     // TODO T184662680: While this is not a correctness issue,
                     // we should fully support relaxed init methods in
                     // class-merging.
-                    bool relaxed = m_config.relaxed_init_inline &&
-                                   m_shrinker.min_sdk() >= 21 &&
-                                   !klass::maybe_anonymous_class(
-                                       type_class(init_method->get_class())) &&
-                                   !is_finalizable(init_method->get_class());
+
+                    // We also don't want to inline constructors of throwable
+                    // (exception, error) classes, as they capture the current
+                    // stack trace in a way that is sensitive to inlining.
+                    bool relaxed =
+                        m_config.relaxed_init_inline &&
+                        m_shrinker.min_sdk() >= 21 &&
+                        !klass::maybe_anonymous_class(
+                            type_class(init_method->get_class())) &&
+                        !is_finalizable(init_method->get_class()) &&
+                        (!m_config.strict_throwable_init_inline ||
+                         !type::check_cast(init_method->get_class(),
+                                           type::java_lang_Throwable()));
                     return constructor_analysis::can_inline_init(
                         init_method, finalizable_fields, relaxed);
                   })