oil: change std::stack reference to a std::function (#345)

Summary:

Previously on large types OIL would have problems with corrupting the `std::stack<exporter::inst::Inst>` that is passed to the processors. This change hides the implementation of the stack from the processors by wrapping the call to emplace in a `std::function` written by the non-generated code, which solves the test case I've seen for this crashing. It also allows us to easily change the stack implementation in future - I plan to change it to a `std::stack<T, std::vector<T>>` in a follow up.

Reviewed By: tyroguru

Differential Revision: D49273116

include/oi/exporters/inst.h

@@ -23,8 +23,8 @@
 
 #include <array>
 #include <cstdint>
+#include <functional>
 #include <initializer_list>
-#include <stack>
 #include <utility>
 #include <variant>
 
@@ -34,7 +34,9 @@ struct PopTypePath;
 struct Field;
 
 using Inst = std::variant<PopTypePath, std::reference_wrapper<const Field>>;
-using Processor = void (*)(result::Element&, std::stack<Inst>&, ParsedData);
+using Processor = void (*)(result::Element&,
+                           std::function<void(Inst)>,
+                           ParsedData);
 using ProcessorInst = std::pair<types::dy::Dynamic, Processor>;
 
 struct PopTypePath {};

oi/CodeGen.cpp

@@ -948,7 +948,8 @@ void genContainerTypeHandler(FeatureSet features,
     code += "  static void processor_";
     code += std::to_string(count++);
     code +=
-        "(result::Element& el, std::stack<inst::Inst>& ins, ParsedData d) {\n";
+        "(result::Element& el, std::function<void(inst::Inst)> stack_ins, "
+        "ParsedData d) {\n";
     code += pr.func;  // bad indentation
     code += "  }\n";
   }

oi/FuncGen.cpp

@@ -726,10 +726,10 @@ void FuncGen::DefineBasicTypeHandlers(std::string& code, FeatureSet features) {
 )";
   if (features[Feature::TreeBuilderV2]) {
     code += R"(private:
-        static void process_pointer(result::Element& el, std::stack<inst::Inst>& ins, ParsedData d) {
+        static void process_pointer(result::Element& el, std::function<void(inst::Inst)> stack_ins, ParsedData d) {
           el.pointer = std::get<ParsedData::VarInt>(d.val).value;
         }
-        static void process_pointer_content(result::Element& el, std::stack<inst::Inst>& ins, ParsedData d) {
+        static void process_pointer_content(result::Element& el, std::function<void(inst::Inst)> stack_ins, ParsedData d) {
           static constexpr std::array<std::string_view, 1> names{"TODO"};
           static constexpr auto childField = inst::Field{
             sizeof(T),
@@ -747,7 +747,7 @@ void FuncGen::DefineBasicTypeHandlers(std::string& code, FeatureSet features) {
             return;
 
           el.container_stats->length = 1;
-          ins.emplace(childField);
+          stack_ins(childField);
         }
 
         static constexpr auto choose_fields() {
@@ -862,7 +862,7 @@ el.container_stats.emplace(result::Element::ContainerStats{ .capacity = N0, .len
 auto list = std::get<ParsedData::List>(d.val);
 // assert(list.length == N0);
 for (size_t i = 0; i < N0; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 )",
   });
 

oi/IntrospectionResult.cpp

@@ -62,7 +62,8 @@ IntrospectionResult::const_iterator::operator++() {
 
             for (const auto& [dy, handler] : ty.processors) {
               auto parsed = exporters::ParsedData::parse(data_, dy);
-              handler(*next_, stack_, parsed);
+              handler(
+                  *next_, [this](auto i) { stack_.emplace(i); }, parsed);
             }
             for (auto it = ty.fields.rbegin(); it != ty.fields.rend(); ++it) {
               stack_.emplace(*it);

types/array_type.toml

@@ -71,5 +71,5 @@ size_t size = std::get<ParsedData::List>(d.val).length;
 el.exclusive_size = N0 == 0 ? 1 : 0;
 el.container_stats.emplace(result::Element::ContainerStats{ .capacity = size, .length = size });
 for (size_t i = 0; i < size; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/f14_fast_map.toml

@@ -120,5 +120,5 @@ static constexpr inst::Field element{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/f14_fast_set.toml

@@ -99,5 +99,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/f14_node_map.toml

@@ -120,5 +120,5 @@ static constexpr inst::Field element{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/f14_node_set.toml

@@ -99,5 +99,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/f14_value_map.toml

@@ -120,5 +120,5 @@ static constexpr inst::Field element{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/f14_value_set.toml

@@ -99,5 +99,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/f14_vector_map.toml

@@ -120,5 +120,5 @@ static constexpr inst::Field element{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/f14_vector_set.toml

@@ -99,5 +99,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/map_seq_type.toml

@@ -120,5 +120,5 @@ el.container_stats->length = list.length;
 el.exclusive_size += (el.container_stats->capacity - el.container_stats->length) * sizeof(element_type);
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(entry);
+  stack_ins(entry);
 '''

types/multi_map_type.toml

@@ -155,5 +155,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 });
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/multi_set_type.toml

@@ -138,5 +138,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 el.exclusive_size += el.container_stats->length * (element_size - sizeof(T0));
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/optional_type.toml

@@ -81,6 +81,6 @@ el.container_stats = result::Element::ContainerStats {
 
 if (sum.index == 1) {
   el.exclusive_size -= sizeof(T0);
-  ins.emplace(elementField);
+  stack_ins(elementField);
 }
 """

types/pair_type.toml

@@ -62,6 +62,6 @@ static constexpr auto firstField = make_field<DB, T0>("first");
 static constexpr auto secondField = make_field<DB, T1>("second");
 
 el.exclusive_size = sizeof(std::pair<T0, T1>) - sizeof(T0) - sizeof(T1);
-ins.emplace(secondField);
-ins.emplace(firstField);
+stack_ins(secondField);
+stack_ins(firstField);
 """

types/seq_type.toml

@@ -102,5 +102,5 @@ el.container_stats->length = list.length;
 el.exclusive_size += (el.container_stats->capacity - el.container_stats->length) * sizeof(T0);
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/set_type.toml

@@ -142,5 +142,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 el.exclusive_size += el.container_stats->length * (element_size - sizeof(T0));
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/shrd_ptr_type.toml

@@ -120,7 +120,7 @@ el.container_stats.emplace(result::Element::ContainerStats {
 if constexpr (!std::is_void<T0>::value) {
   if (sum.index == 1) {
     static constexpr auto element = make_field<DB, T0>("ptr_val");
-    ins.emplace(element);
+    stack_ins(element);
   }
 }
 """

types/small_vec_type.toml

@@ -126,5 +126,5 @@ if (uses_intern_storage) {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/std_map_type.toml

@@ -163,5 +163,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 });
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/std_unordered_map_type.toml

@@ -160,5 +160,5 @@ static constexpr auto element = inst::Field{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/std_unordered_multimap_type.toml

@@ -160,5 +160,5 @@ static constexpr auto element = inst::Field{
 };
 
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(element);
+  stack_ins(element);
 """

types/uniq_ptr_type.toml

@@ -106,7 +106,7 @@ el.container_stats.emplace(result::Element::ContainerStats {
 if constexpr (!std::is_void<T0>::value) {
   if (sum.index == 1) {
     static constexpr auto element = make_field<DB, T0>("ptr_val");
-    ins.emplace(element);
+    stack_ins(element);
   }
 }
 """

types/unordered_multiset_type.toml

@@ -133,5 +133,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """

types/unordered_set_type.toml

@@ -133,5 +133,5 @@ el.container_stats.emplace(result::Element::ContainerStats {
 
 static constexpr auto childField = make_field<DB, T0>("[]");
 for (size_t i = 0; i < list.length; i++)
-  ins.emplace(childField);
+  stack_ins(childField);
 """