Make thread_local variables constinit (#1206)

By declaring all thread_local variables that can easily be given static
initialization constinit, and removing the destructor of `arena`, we can
remove the call to `__tls_init` which is inserted into every single
allocation, significantly speeding up the code. One consequence of this
is that threads are responsible for calling munmap explicitly before
exiting now; my understanding is they are pretty much always doing this
currently via `free_all_kore_mem`, so this shouldn't break anything, but
it needs testing to make sure.

Author: dwightguth

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 3.5)
+cmake_minimum_required (VERSION 3.12)
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
 
@@ -12,6 +12,9 @@ project(KLLVM CXX C)
 
 set(CMAKE_DISABLE_SOURCE_CHANGES  ON)
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
+set(CMAKE_CXX_STANDARD          20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS        OFF)
 
 include(CTest)
 

bin/llvm-kompile-clang

@@ -50,7 +50,7 @@ infer_library_name() {
   fi
 }
 
-clangpp_args=("--std=c++17")
+clangpp_args=("--std=c++20")
 while [[ $# -gt 0 ]]; do
   if $output; then
     output=false

cmake/KLLVMCompilerFlags.cmake

@@ -1,7 +1,3 @@
-set(CMAKE_CXX_STANDARD          20)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_EXTENSIONS        OFF)
-
 # Required to build the Python bindings as a static library that is then linked
 # into a shared library with the interpreter library generated by llvm-kompile.
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)

cmake/LLVMKompile.cmake

@@ -1,6 +1,6 @@
 set(CMAKE_DISABLE_SOURCE_CHANGES ON)
 set(CMAKE_DISABLE_IN_SOURCE_BUILD ON)
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 

include/runtime/arena.h

@@ -29,17 +29,10 @@ size_t const MIN_SPACE = 1024 * 1024;
 // once.
 class arena {
 public:
-  arena(char id, bool trigger_collection)
+  constexpr arena(char id, bool trigger_collection)
       : allocation_semispace_id(id)
       , trigger_collection(trigger_collection) { }
 
-  ~arena() {
-    if (current_addr_ptr)
-      munmap(current_addr_ptr, HYPERBLOCK_SIZE);
-    if (collection_addr_ptr)
-      munmap(collection_addr_ptr, HYPERBLOCK_SIZE);
-  }
-
   char *evacuate(char *scan_ptr);
 
   // Allocates the requested number of bytes as a contiguous region and returns a
@@ -163,7 +156,7 @@ inline char arena::get_arena_semispace_id_of_object(void *ptr) {
 //
 extern bool time_for_collection;
 #else
-extern thread_local bool time_for_collection;
+extern thread_local constinit bool time_for_collection;
 #endif
 
 size_t get_gc_threshold();

include/runtime/collect.h

@@ -26,8 +26,8 @@ using set_node = set::iterator::node_t;
 using set_impl = set::iterator::tree_t;
 
 extern "C" {
-extern thread_local size_t numBytesLiveAtCollection[1 << AGE_WIDTH];
-extern thread_local bool collect_old;
+extern thread_local constinit size_t numBytesLiveAtCollection[1 << AGE_WIDTH];
+extern thread_local constinit bool collect_old;
 size_t get_size(uint64_t, uint16_t);
 void migrate_static_roots(void);
 void migrate(block **block_ptr);

include/runtime/header.h

@@ -53,7 +53,7 @@ void hash_exit(void);
 //
 extern bool gc_enabled;
 #else
-extern thread_local bool gc_enabled;
+extern thread_local constinit bool gc_enabled;
 #endif
 }
 

runtime/alloc/arena.cpp

@@ -19,8 +19,8 @@ extern size_t const VAR_BLOCK_SIZE = BLOCK_SIZE;
 bool time_for_collection = false;
 bool gc_enabled = true;
 #else
-thread_local bool time_for_collection = false;
-thread_local bool gc_enabled = true;
+thread_local constinit bool time_for_collection = false;
+thread_local constinit bool gc_enabled = true;
 #endif
 
 void arena::initialize_semispace() {

runtime/arithmetic/int.cpp

@@ -374,7 +374,7 @@ void int_hash(mpz_t i, void *hasher) {
 }
 
 thread_local gmp_randstate_t kllvm_rand_state;
-thread_local bool kllvm_rand_state_initialized = false;
+thread_local constinit bool kllvm_rand_state_initialized = false;
 
 SortK hook_INT_srand(SortInt seed) {
   if (!kllvm_rand_state_initialized) {

runtime/collect/collect.cpp

@@ -10,22 +10,22 @@
 #include <cstring>
 
 extern "C" {
-extern thread_local arena youngspace;
-extern thread_local arena oldspace;
-extern thread_local arena alwaysgcspace;
+extern thread_local constinit arena youngspace;
+extern thread_local constinit arena oldspace;
+extern thread_local constinit arena alwaysgcspace;
 
 char *youngspace_ptr(void);
 char *oldspace_ptr(void);
 
 static thread_local bool is_gc = false;
-bool thread_local collect_old = false;
+bool thread_local constinit collect_old = false;
 #ifndef GC_DBG
 static thread_local uint8_t num_collection_only_young = 0;
 #else
 static thread_local char *last_alloc_ptr;
 #endif
 
-size_t thread_local numBytesLiveAtCollection[1 << AGE_WIDTH];
+size_t thread_local constinit numBytesLiveAtCollection[1 << AGE_WIDTH];
 
 bool during_gc() {
   return is_gc;