[refactor] Remove SNodeAttr and decouple SNode from LLVM (taichi-…

…dev#817)

taichi/codegen/codegen_llvm.cpp

@@ -1,5 +1,7 @@
 #include "codegen_llvm.h"
 
+#include "taichi/struct/struct_llvm.h"
+
 TLANG_NAMESPACE_BEGIN
 
 // TODO: sort function definitions to match declaration order in header
@@ -206,14 +208,6 @@ std::unique_ptr<RuntimeObject> CodeGenLLVM::emit_struct_meta_object(
     TI_P(snode_type_name(snode->type));
     TI_NOT_IMPLEMENTED;
   }
-  if (false) {
-    // auto ptr_type = llvm::Type::getInt8PtrTy(*llvm_context, 0);
-    auto ptr_type = llvm::PointerType::get(meta->type, 0);
-    auto ptr = meta->ptr;  // builder->CreatePointerCast(meta->ptr, ptr_type);
-    auto struct_meta_size = tlctx->get_type_size(meta->type);
-    builder->CreateIntrinsic(llvm::Intrinsic::invariant_start, {ptr_type},
-                             {tlctx->get_constant(struct_meta_size), ptr});
-  }
   return meta;
 }
 
@@ -223,13 +217,17 @@ void CodeGenLLVM::emit_struct_meta_base(const std::string &name,
   RuntimeObject common("StructMeta", this, builder.get(), node_meta);
   std::size_t element_size;
   if (snode->type == SNodeType::dense) {
-    auto element_ty = snode_attr[snode].llvm_body_type->getArrayElementType();
+    auto body_type =
+        StructCompilerLLVM::get_llvm_body_type(module.get(), snode);
+    auto element_ty = body_type->getArrayElementType();
     element_size = tlctx->get_type_size(element_ty);
   } else if (snode->type == SNodeType::pointer) {
-    auto element_ty = tlctx->snode_attr[snode->ch[0]].llvm_type;
+    auto element_ty = StructCompilerLLVM::get_llvm_node_type(
+        module.get(), snode->ch[0].get());
     element_size = tlctx->get_type_size(element_ty);
   } else {
-    auto element_ty = tlctx->snode_attr[snode].llvm_element_type;
+    auto element_ty =
+        StructCompilerLLVM::get_llvm_element_type(module.get(), snode);
     element_size = tlctx->get_type_size(element_ty);
   }
   common.set("snode_id", tlctx->get_constant(snode->id));
@@ -266,13 +264,12 @@ void CodeGenLLVM::emit_struct_meta_base(const std::string &name,
 }
 
 CodeGenLLVM::CodeGenLLVM(Kernel *kernel, IRNode *ir)
-    // TODO: simplify ModuleBuilder ctor input
-    : ModuleBuilder(kernel->program.get_llvm_context(kernel->arch)
-                        ->clone_struct_module()),
+    // TODO: simplify LLVMModuleBuilder ctor input
+    : LLVMModuleBuilder(kernel->program.get_llvm_context(kernel->arch)
+                            ->clone_struct_module()),
       kernel(kernel),
       ir(ir),
-      prog(&kernel->program),
-      snode_attr(prog->get_llvm_context(kernel->arch)->snode_attr) {
+      prog(&kernel->program) {
   if (ir == nullptr)
     this->ir = kernel->ir;
   initialize_context();
@@ -1117,8 +1114,9 @@ llvm::Value *CodeGenLLVM::call(SNode *snode,
 
 void CodeGenLLVM::visit(GetRootStmt *stmt) {
   llvm_val[stmt] = builder->CreateBitCast(
-      get_root(),
-      PointerType::get(snode_attr[prog->snode_root.get()].llvm_type, 0));
+      get_root(), PointerType::get(StructCompilerLLVM::get_llvm_node_type(
+                                       module.get(), prog->snode_root.get()),
+                                   0));
 }
 
 void CodeGenLLVM::visit(OffsetAndExtractBitsStmt *stmt) {
@@ -1184,7 +1182,9 @@ void CodeGenLLVM::visit(GetChStmt *stmt) {
       {builder->CreateBitCast(llvm_val[stmt->input_ptr],
                               PointerType::getInt8PtrTy(*llvm_context))});
   llvm_val[stmt] = builder->CreateBitCast(
-      ch, PointerType::get(snode_attr[stmt->output_snode].llvm_type, 0));
+      ch, PointerType::get(StructCompilerLLVM::get_llvm_node_type(
+                               module.get(), stmt->output_snode),
+                           0));
 }
 
 void CodeGenLLVM::visit(ExternalPtrStmt *stmt) {

taichi/codegen/codegen_llvm.h

@@ -48,7 +48,7 @@ class FunctionCreationGuard {
   ~FunctionCreationGuard();
 };
 
-class CodeGenLLVM : public IRVisitor, public ModuleBuilder {
+class CodeGenLLVM : public IRVisitor, public LLVMModuleBuilder {
  public:
   static uint64 task_counter;
 
@@ -66,15 +66,14 @@ class CodeGenLLVM : public IRVisitor, public ModuleBuilder {
   llvm::BasicBlock *current_while_after_loop;
   llvm::FunctionType *task_function_type;
   OffloadedStmt *current_offloaded_stmt;
-  SNodeAttributes &snode_attr;
   std::unordered_map<Stmt *, llvm::Value *> llvm_val;
   llvm::Function *func;
   std::unique_ptr<OffloadedTask> current_task;
   std::vector<OffloadedTask> offloaded_tasks;
   BasicBlock *func_body_bb;
 
   using IRVisitor::visit;
-  using ModuleBuilder::call;
+  using LLVMModuleBuilder::call;
 
   CodeGenLLVM(Kernel *kernel, IRNode *ir = nullptr);
 

taichi/codegen/codegen_llvm_cuda.cpp

@@ -135,7 +135,7 @@ class CodeGenLLVMCUDA : public CodeGenLLVM {
 
     auto format_str = "[debug] " + stmt->str + " = " + format + "\n";
 
-    llvm_val[stmt] = ModuleBuilder::call(
+    llvm_val[stmt] = LLVMModuleBuilder::call(
         builder.get(), "vprintf",
         builder->CreateGlobalStringPtr(format_str, "format_string"),
         builder->CreateBitCast(values,

taichi/ir/snode.h

@@ -256,28 +256,4 @@ class SNode {
   uint64 fetch_reader_result();  // TODO: refactor
 };
 
-class SNodeAttribute {
- public:
-  llvm::Type *llvm_type, *llvm_body_type, *llvm_aux_type;
-  llvm::Type *llvm_element_type;
-};
-
-class SNodeAttributes {
- private:
-  std::map<SNode *, SNodeAttribute> snode_llvm_attr;
-
- public:
-  SNodeAttribute &operator[](SNode &snode) {
-    return snode_llvm_attr[&snode];
-  }
-
-  SNodeAttribute &operator[](SNode *snode) {
-    return snode_llvm_attr[snode];
-  }
-
-  SNodeAttribute &operator[](const std::unique_ptr<SNode> &snode) {
-    return snode_llvm_attr[snode.get()];
-  }
-};
-
 TLANG_NAMESPACE_END

taichi/llvm/llvm_codegen_utils.h

@@ -50,15 +50,15 @@ inline bool check_func_call_signature(llvm::Value *func, Args &&... args) {
   return check_func_call_signature(func, {args...});
 }
 
-class ModuleBuilder {
+class LLVMModuleBuilder {
  public:
   std::unique_ptr<llvm::Module> module;
   llvm::BasicBlock *entry_block;
   std::unique_ptr<llvm::IRBuilder<>> builder;
   TaichiLLVMContext *tlctx;
   llvm::LLVMContext *llvm_context;
 
-  ModuleBuilder(std::unique_ptr<llvm::Module> &&module)
+  LLVMModuleBuilder(std::unique_ptr<llvm::Module> &&module)
       : module(std::move(module)) {
   }
 
@@ -131,12 +131,12 @@ class RuntimeObject {
  public:
   std::string cls_name;
   llvm::Value *ptr;
-  ModuleBuilder *mb;
+  LLVMModuleBuilder *mb;
   llvm::Type *type;
   llvm::IRBuilder<> *builder;
 
   RuntimeObject(const std::string &cls_name,
-                ModuleBuilder *mb,
+                LLVMModuleBuilder *mb,
                 llvm::IRBuilder<> *builder,
                 llvm::Value *init = nullptr)
       : cls_name(cls_name), mb(mb), builder(builder) {

taichi/llvm/llvm_context.h

@@ -24,8 +24,6 @@ class TaichiLLVMContext {
   std::mutex mut;
   Arch arch;
 
-  SNodeAttributes snode_attr;
-
   TaichiLLVMContext(Arch arch);
 
   std::unique_ptr<llvm::Module> get_init_module();

taichi/program/program.cpp

@@ -11,6 +11,7 @@
 #include "taichi/codegen/codegen_opengl.h"
 #include "taichi/codegen/codegen_cpu.h"
 #include "taichi/struct/struct.h"
+#include "taichi/struct/struct_llvm.h"
 #include "taichi/struct/struct_metal.h"
 #include "taichi/struct/struct_opengl.h"
 #include "taichi/system/unified_allocator.h"
@@ -215,15 +216,15 @@ void Program::initialize_runtime_system(StructCompiler *scomp) {
   for (int i = 0; i < (int)snodes.size(); i++) {
     if (is_gc_able(snodes[i]->type)) {
       std::size_t node_size;
-      if (snodes[i]->type == SNodeType::pointer)
-        node_size = tlctx->get_type_size(
-            scomp->snode_attr[snodes[i]].llvm_element_type);
-      else {
+      auto element_size =
+          tlctx->get_type_size(StructCompilerLLVM::get_llvm_element_type(
+              tlctx->struct_module.get(), snodes[i]));
+      if (snodes[i]->type == SNodeType::pointer) {
+        // pointer. Allocators are for single elements
+        node_size = element_size;
+      } else {
         // dynamic. Allocators are for the chunks
-        node_size = sizeof(void *) +
-                    tlctx->get_type_size(
-                        scomp->snode_attr[snodes[i]].llvm_element_type) *
-                        snodes[i]->chunk_size;
+        node_size = sizeof(void *) + element_size * snodes[i]->chunk_size;
       }
       TI_TRACE("Initializing allocator for snode {} (node size {})",
                snodes[i]->id, node_size);

taichi/struct/struct.h

@@ -14,8 +14,6 @@ class StructCompiler {
   std::size_t root_size;
   Program *prog;
 
-  SNodeAttributes snode_attr;
-
   explicit StructCompiler(Program *prog);
 
   virtual ~StructCompiler() = default;

taichi/struct/struct_llvm.cpp

@@ -13,7 +13,7 @@ using namespace llvm;
 
 StructCompilerLLVM::StructCompilerLLVM(Program *prog, Arch arch)
     : StructCompiler(prog),
-      ModuleBuilder(prog->get_llvm_context(arch)->get_init_module()),
+      LLVMModuleBuilder(prog->get_llvm_context(arch)->get_init_module()),
       arch(arch) {
   tlctx = prog->get_llvm_context(arch);
   llvm_ctx = tlctx->ctx.get();
@@ -22,23 +22,20 @@ StructCompilerLLVM::StructCompilerLLVM(Program *prog, Arch arch)
 void StructCompilerLLVM::generate_types(SNode &snode) {
   TI_AUTO_PROF;
   auto type = snode.type;
-  llvm::Type *llvm_type = nullptr;
+  llvm::Type *node_type = nullptr;
 
   auto ctx = llvm_ctx;
 
   // create children type that supports forking...
 
   std::vector<llvm::Type *> ch_types;
   for (int i = 0; i < snode.ch.size(); i++) {
-    auto ch = snode_attr[snode.ch[i]].llvm_type;
+    auto ch = get_llvm_node_type(module.get(), snode.ch[i].get());
     ch_types.push_back(ch);
   }
 
   auto ch_type =
       llvm::StructType::create(*ctx, ch_types, snode.node_type_name + "_ch");
-  ch_type->setName(snode.node_type_name + "_ch");
-
-  snode_attr[snode].llvm_element_type = ch_type;
 
   llvm::Type *body_type = nullptr, *aux_type = nullptr;
   if (type == SNodeType::dense || type == SNodeType::bitmasked) {
@@ -69,15 +66,21 @@ void StructCompilerLLVM::generate_types(SNode &snode) {
     TI_NOT_IMPLEMENTED;
   }
   if (aux_type != nullptr) {
-    llvm_type = llvm::StructType::create(*ctx, {aux_type, body_type}, "");
+    node_type = llvm::StructType::create(*ctx, {aux_type, body_type}, "");
   } else {
-    llvm_type = body_type;
+    node_type = body_type;
   }
 
-  TI_ASSERT(llvm_type != nullptr);
-  snode_attr[snode].llvm_type = llvm_type;
-  snode_attr[snode].llvm_aux_type = aux_type;
-  snode_attr[snode].llvm_body_type = body_type;
+  TI_ASSERT(node_type != nullptr);
+  TI_ASSERT(body_type != nullptr);
+
+  // Here we create a stub holding 4 LLVM types as struct members.
+  // The aim is to give a **unique** name to the stub, so that we can look up
+  // these types using this name. This decouples them from the LLVM context.
+  // Note that body_type might not have a unique name, since literal structs
+  // (such as {i32, i32}) are uniqued in LLVM.
+  llvm::StructType::create(*ctx, {node_type, body_type, aux_type, ch_type},
+                           type_stub_name(&snode));
 }
 
 void StructCompilerLLVM::generate_refine_coordinates(SNode *snode) {
@@ -140,7 +143,7 @@ void StructCompilerLLVM::generate_child_accessors(SNode &snode) {
     auto parent = snode.parent;
 
     auto inp_type =
-        llvm::PointerType::get(snode_attr[parent].llvm_element_type, 0);
+        llvm::PointerType::get(get_llvm_element_type(module.get(), parent), 0);
 
     auto ft =
         llvm::FunctionType::get(llvm::Type::getInt8PtrTy(*llvm_ctx),
@@ -174,6 +177,10 @@ void StructCompilerLLVM::generate_child_accessors(SNode &snode) {
   stack.pop_back();
 }
 
+std::string StructCompilerLLVM::type_stub_name(SNode *snode) {
+  return snode->node_type_name + "_type_stubs";
+}
+
 void StructCompilerLLVM::run(SNode &root, bool host) {
   TI_AUTO_PROF;
   // bottom to top
@@ -197,11 +204,44 @@ void StructCompilerLLVM::run(SNode &root, bool host) {
 
   TI_ASSERT((int)snodes.size() <= taichi_max_num_snodes);
 
-  root_size =
-      tlctx->get_data_layout().getTypeAllocSize(snode_attr[root].llvm_type);
+  auto node_type = get_llvm_node_type(module.get(), &root);
+  root_size = tlctx->get_data_layout().getTypeAllocSize(node_type);
 
   tlctx->set_struct_module(module);
-  tlctx->snode_attr = snode_attr;
+}
+
+llvm::Type *StructCompilerLLVM::get_stub(llvm::Module *module,
+                                         SNode *snode,
+                                         uint32 index) {
+  TI_ASSERT(module);
+  TI_ASSERT(snode);
+  auto stub = module->getTypeByName(type_stub_name(snode));
+  TI_ASSERT(stub);
+  TI_ASSERT(stub->getStructNumElements() == 4);
+  TI_ASSERT(0 <= index && index < 4);
+  auto type = stub->getContainedType(index);
+  TI_ASSERT(type);
+  return type;
+}
+
+llvm::Type *StructCompilerLLVM::get_llvm_node_type(llvm::Module *module,
+                                                   SNode *snode) {
+  return get_stub(module, snode, 0);
+}
+
+llvm::Type *StructCompilerLLVM::get_llvm_body_type(llvm::Module *module,
+                                                   SNode *snode) {
+  return get_stub(module, snode, 1);
+}
+
+llvm::Type *StructCompilerLLVM::get_llvm_aux_type(llvm::Module *module,
+                                                  SNode *snode) {
+  return get_stub(module, snode, 2);
+}
+
+llvm::Type *StructCompilerLLVM::get_llvm_element_type(llvm::Module *module,
+                                                      SNode *snode) {
+  return get_stub(module, snode, 3);
 }
 
 std::unique_ptr<StructCompiler> StructCompiler::make(Program *prog, Arch arch) {

taichi/struct/struct_llvm.h

@@ -1,11 +1,11 @@
 // Codegen for the hierarchical data structure (LLVM)
 
-#include "struct.h"
+#include "taichi/struct/struct.h"
 #include "taichi/llvm/llvm_codegen_utils.h"
 
 TLANG_NAMESPACE_BEGIN
 
-class StructCompilerLLVM : public StructCompiler, public ModuleBuilder {
+class StructCompilerLLVM : public StructCompiler, public LLVMModuleBuilder {
  public:
   StructCompilerLLVM(Program *prog, Arch arch);
 
@@ -20,6 +20,18 @@ class StructCompilerLLVM : public StructCompiler, public ModuleBuilder {
   void run(SNode &node, bool host) override;
 
   void generate_refine_coordinates(SNode *snode);
+
+  static std::string type_stub_name(SNode *snode);
+
+  static llvm::Type *get_stub(llvm::Module *module, SNode *snode, uint32 index);
+
+  static llvm::Type *get_llvm_node_type(llvm::Module *module, SNode *snode);
+
+  static llvm::Type *get_llvm_body_type(llvm::Module *module, SNode *snode);
+
+  static llvm::Type *get_llvm_aux_type(llvm::Module *module, SNode *snode);
+
+  static llvm::Type *get_llvm_element_type(llvm::Module *module, SNode *snode);
 };
 
 TLANG_NAMESPACE_END