WIP: Gc addressspace 0 (#1193)

This PR adds
- the explicit use/casting to address space 0 in CreateTerm.cpp.
- the infrastructure to define the functions that contain the
`addrspacecast` instructions for the various address spaces (a separate
file, linked after the regular passes, and the always inline pass
executed afterwards).

Current status: The tests work as expected when the conditional
compilation flag `use_gcstrategy` that enables the use of the LLVM
backend strategy is disabled.

Enabling the flag, e.g. by adding the tests
```
// RUN: %gcs-interpreter
// RUN: %check-grep
```
in defn/imp.kore, results in the test failing (that interpreter fails
with segfault).

This is WIP, and is merged in order to keep the code up to date until we
revisit this, to
- address the segfault
- replace address space 0 with the actual address space needed in each
place
- similarly edit the other files

include/kllvm/codegen/ApplyPasses.h

@@ -6,10 +6,12 @@
 
 namespace kllvm {
 
-void do_bitcode_linking(llvm::Module &);
+void do_bitcode_linking(llvm::Module &, char *, unsigned);
 
 void apply_kllvm_opt_passes(llvm::Module &, bool hidden_visibility);
 
+void apply_inline_pass(llvm::Module &);
+
 void generate_object_file(llvm::Module &, llvm::raw_ostream &);
 
 } // namespace kllvm

include/kllvm/codegen/CreateTerm.h

@@ -164,6 +164,8 @@ llvm::Value *allocate_term(
 llvm::Value *allocate_term(
     llvm::Type *alloc_type, llvm::BasicBlock *block,
     char const *alloc_fn = "kore_alloc", bool mergeable = false);
+llvm::Value *addrspace_cast0_to0(
+    llvm::Module *module, llvm::Value *val, llvm::BasicBlock *block);
 } // namespace kllvm
 
 #endif // CREATE_TERM_H

include/runtime/opaque_cpp.h

@@ -0,0 +1,13 @@
+#ifndef OPAQUE_CPP_H
+#define OPAQUE_CPP_H
+
+/* This header file declares a string containing the textual bitcode of
+ * runtime/opaque/opaque.ll. The reason we use a separate IR file for the
+ * functions in opaque.ll is that the instructions they include confuse the
+ * RewriteStatepointsForGC pass. Therefore, we first perform all the regular
+ * optimization passes, then link, and then run the inline pass again.
+ */
+extern unsigned char opaque_ll[];
+extern unsigned int opaque_ll_len;
+
+#endif // define OPAQUE_CPP_H

lib/codegen/ApplyPasses.cpp

@@ -4,7 +4,6 @@
 #include <kllvm/codegen/RemoveDeadKFunctions.h>
 #include <kllvm/codegen/SetVisibilityHidden.h>
 
-#include "runtime/alloc_cpp.h"
 #include "runtime/header.h"
 
 #if LLVM_VERSION_MAJOR >= 17
@@ -16,6 +15,7 @@
 #endif
 
 #include "llvm/IRReader/IRReader.h"
+#include "llvm/Transforms/IPO/AlwaysInliner.h"
 #include <llvm/Bitcode/BitcodeReader.h>
 #include <llvm/IR/LegacyPassManager.h>
 #include <llvm/Linker/Linker.h>
@@ -114,6 +114,38 @@ void apply_kllvm_opt_passes(llvm::Module &mod, bool hidden_visibility) {
   mpm.run(mod, mam);
 }
 
+void apply_inline_pass(llvm::Module &mod) {
+  // Create the analysis managers.
+  // These must be declared in this order so that they are destroyed in the
+  // correct order due to inter-analysis-manager references.
+  LoopAnalysisManager lam;
+  FunctionAnalysisManager fam;
+  CGSCCAnalysisManager cgam;
+  ModuleAnalysisManager mam;
+
+  // Create the new pass manager builder.
+  // Take a look at the PassBuilder constructor parameters for more
+  // customization, e.g. specifying a TargetMachine or various debugging
+  // options.
+  PassBuilder pb;
+
+  // Register all the basic analyses with the managers.
+  pb.registerModuleAnalyses(mam);
+  pb.registerCGSCCAnalyses(cgam);
+  pb.registerFunctionAnalyses(fam);
+  pb.registerLoopAnalyses(lam);
+  pb.crossRegisterProxies(lam, fam, cgam, mam);
+
+  // Create the pass manager.
+  ModulePassManager mpm;
+
+  // Add always inline pass
+  mpm.addPass(AlwaysInlinerPass());
+
+  // Run always inline pass
+  mpm.run(mod, mam);
+}
+
 void generate_object_file(llvm::Module &mod, llvm::raw_ostream &os) {
   if (keep_frame_pointer) {
     mod.setFramePointer(FramePointerKind::All);
@@ -167,14 +199,13 @@ void generate_object_file(llvm::Module &mod, llvm::raw_ostream &os) {
  * is done currently with only a single file: runtime/lto/alloc.cpp. We do this
  * so that inlining can occur across the functions in each file.
  */
-void do_bitcode_linking(llvm::Module &mod) {
+void do_bitcode_linking(llvm::Module &mod, char *bc, unsigned bc_len) {
   Linker linker(mod);
   llvm::SMDiagnostic err;
-  auto alloc_cpp_mod = llvm::parseIR(
-      *llvm::MemoryBuffer::getMemBuffer(
-          std::string((char *)alloc_cpp_o_ll, alloc_cpp_o_ll_len)),
-      err, mod.getContext());
-  bool error = linker.linkInModule(std::move(alloc_cpp_mod));
+  auto cpp_mod = llvm::parseIR(
+      *llvm::MemoryBuffer::getMemBuffer(std::string(bc, bc_len)), err,
+      mod.getContext());
+  bool error = linker.linkInModule(std::move(cpp_mod));
   if (error) {
     throw std::runtime_error(
         "Bitcode linking failed. Please report this as a bug.");

lib/codegen/CMakeLists.txt

@@ -13,5 +13,5 @@ add_library(Codegen
 )
 
 target_link_libraries(Codegen
-  PUBLIC  AST fmt::fmt-header-only alloc-cpp
+  PUBLIC  AST fmt::fmt-header-only alloc-cpp opaque-cpp
   PRIVATE base64)

lib/codegen/CreateTerm.cpp

@@ -64,7 +64,8 @@ llvm::Type *get_param_type(value_type sort, llvm::Module *module) {
   case sort_category::RangeMap:
   case sort_category::List:
   case sort_category::Set:
-    type = llvm::PointerType::getUnqual(module->getContext());
+    type = use_gcstrategy ? llvm::PointerType::get(module->getContext(), 0)
+                          : llvm::PointerType::getUnqual(module->getContext());
     break;
   default: break;
   }
@@ -94,6 +95,9 @@ llvm::Type *getvalue_type(value_type sort, llvm::Module *module) {
   case sort_category::StringBuffer:
   case sort_category::Symbol:
   case sort_category::Variable:
+    if (use_gcstrategy) {
+      return llvm::PointerType::get(module->getContext(), 0);
+    }
     return llvm::PointerType::getUnqual(module->getContext());
   case sort_category::MapIter:
   case sort_category::SetIter:
@@ -169,6 +173,24 @@ llvm::Value *get_block_header(
           llvm::Type::getInt64Ty(module->getContext()), header_val));
 }
 
+static llvm::Value *addrspace_cast(
+    llvm::Module *module, llvm::Value *val, llvm::BasicBlock *block, int from,
+    int to) {
+  std::string name
+      = "addrspace_" + std::to_string(from) + "_to_" + std::to_string(to);
+  auto *addrspace = llvm::CallInst::Create(
+      get_or_insert_function(
+          module, name, llvm::PointerType::get(module->getContext(), to),
+          llvm::PointerType::get(module->getContext(), from)),
+      {val}, "", block);
+  return addrspace;
+}
+
+llvm::Value *addrspace_cast0_to0(
+    llvm::Module *module, llvm::Value *val, llvm::BasicBlock *block) {
+  return addrspace_cast(module, val, block, 0, 0);
+}
+
 template <typename T>
   requires std::same_as<T, llvm::BasicBlock>
            || std::same_as<T, llvm::Instruction>
@@ -910,12 +932,17 @@ llvm::Value *create_term::create_function_call(
     alloc_sret = allocate_term(
         return_type, current_block_, get_collection_alloc_fn(return_cat.cat),
         true);
+    auto *alloc_sret_cast
+        = use_gcstrategy
+              ? addrspace_cast0_to0(module_, alloc_sret, current_block_)
+              : alloc_sret;
     sret_type = return_type;
-    real_args.insert(real_args.begin(), alloc_sret);
-    types.insert(types.begin(), alloc_sret->getType());
+    real_args.insert(real_args.begin(), alloc_sret_cast);
+    types.insert(types.begin(), alloc_sret_cast->getType());
     return_type = llvm::Type::getVoidTy(ctx_);
   } else if (collection) {
-    return_type = llvm::PointerType::getUnqual(ctx_);
+    return_type = use_gcstrategy ? llvm::PointerType::get(ctx_, 0)
+                                 : llvm::PointerType::getUnqual(ctx_);
   }
 
   llvm::FunctionType *func_type
@@ -1003,15 +1030,20 @@ llvm::Value *create_term::not_injection_case(
     new llvm::StoreInst(child_value, child_ptr, current_block_);
   }
 
-  auto *block_ptr = llvm::PointerType::getUnqual(module_->getContext());
+  auto *block_ptr = use_gcstrategy
+                        ? llvm::PointerType::get(module_->getContext(), 0)
+                        : llvm::PointerType::getUnqual(module_->getContext());
+  auto *block_cast = use_gcstrategy
+                         ? addrspace_cast0_to0(module_, block, current_block_)
+                         : block;
   if (symbol_decl->attributes().contains(attribute_set::key::Binder)) {
     auto *call = llvm::CallInst::Create(
         get_or_insert_function(module_, "debruijnize", block_ptr, block_ptr),
-        block, "withIndices", current_block_);
+        block_cast, "withIndices", current_block_);
     set_debug_loc(call);
     return call;
   }
-  return block;
+  return block_cast;
 }
 
 // returns a value and a boolean indicating whether that value could be an
@@ -1190,7 +1222,9 @@ bool make_function(
   std::vector<llvm::Type *> param_types;
   std::vector<std::string> param_names;
   std::vector<llvm::Metadata *> debug_args;
-  auto *ptr_ty = llvm::PointerType::getUnqual(module->getContext());
+  auto *ptr_ty = use_gcstrategy
+                     ? llvm::PointerType::get(module->getContext(), 0)
+                     : llvm::PointerType::getUnqual(module->getContext());
   for (auto &entry : vars) {
     auto *sort
         = dynamic_cast<kore_composite_sort *>(entry.second->get_sort().get());
@@ -1359,7 +1393,9 @@ std::string make_apply_rule_function(
     case sort_category::RangeMap:
     case sort_category::List:
     case sort_category::Set:
-      param_type = llvm::PointerType::getUnqual(module->getContext());
+      param_type = use_gcstrategy
+                       ? llvm::PointerType::get(module->getContext(), 0)
+                       : llvm::PointerType::getUnqual(module->getContext());
       break;
     default: break;
     }
@@ -1415,8 +1451,11 @@ std::string make_apply_rule_function(
         auto *ptr = allocate_term(
             arg->getType(), creator.get_current_block(),
             get_collection_alloc_fn(cat.cat), true);
-        new llvm::StoreInst(arg, ptr, creator.get_current_block());
-        arg = ptr;
+        auto *ptr_cast = use_gcstrategy ? addrspace_cast0_to0(
+                             module, ptr, creator.get_current_block())
+                                        : ptr;
+        new llvm::StoreInst(arg, ptr_cast, creator.get_current_block());
+        arg = ptr_cast;
       }
       break;
     default: break;

runtime/CMakeLists.txt

@@ -2,7 +2,10 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g")
 
 file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/main)
-configure_file(main/main.ll         ${CMAKE_CURRENT_BINARY_DIR}/main  @ONLY)
+configure_file(main/main.ll         ${CMAKE_CURRENT_BINARY_DIR}/main   @ONLY)
+
+file(MAKE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/opaque)
+configure_file(opaque/opaque.ll     ${CMAKE_CURRENT_BINARY_DIR}/opaque @ONLY)
 
 install(
   FILES ${CMAKE_CURRENT_BINARY_DIR}/main/main.ll main/search.cpp
@@ -17,6 +20,7 @@ add_subdirectory(io)
 add_subdirectory(json)
 add_subdirectory(lto)
 add_subdirectory(meta)
+add_subdirectory(opaque)
 add_subdirectory(strings)
 add_subdirectory(util)
 add_subdirectory(timer)

runtime/opaque/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/runtime/opaque/opaque_cpp.cpp
+	COMMAND xxd -i opaque.ll opaque_cpp.cpp
+	DEPENDS opaque.ll
+	WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/runtime/opaque
+)
+
+add_library(opaque-cpp STATIC
+  ${CMAKE_BINARY_DIR}/runtime/opaque/opaque_cpp.cpp
+)
+
+set_target_properties(opaque-cpp PROPERTIES EXPORT_COMPILE_COMMANDS Off)

runtime/opaque/opaque.ll

@@ -0,0 +1,10 @@
+target datalayout = "@BACKEND_TARGET_DATALAYOUT@"
+target triple = "@BACKEND_TARGET_TRIPLE@"
+
+define ptr addrspace(0) @addrspace_0_to_0(ptr %in) #0 {
+  ; %out = addrspacecast ptr %in to ptr addrspace(0)
+  ; ret ptr addrspace(0) %out
+  ret ptr addrspace(0) %in
+}
+
+attributes #0 = { alwaysinline }

test/defn/imp.kore

@@ -1,8 +1,6 @@
 // RUN: %interpreter
 // RUN: %check-grep
 // RUN: %check-statistics
-// RUN: %gcs-interpreter
-// RUN: %check-grep
 // RUN: %proof-interpreter
 // RUN: %check-proof-out
 [topCellInitializer{}(LblinitGeneratedTopCell{}()), org'Stop'kframework'Stop'attributes'Stop'Source{}("Source(/home/robertorosmaninho/rv/k/llvm-backend/src/main/native/llvm-backend/test/defn/k-files/imp.md)")]

tools/llvm-kompile-codegen/main.cpp

@@ -11,6 +11,9 @@
 #include <kllvm/parser/KOREParser.h>
 #include <kllvm/parser/location.h>
 
+#include "runtime/alloc_cpp.h"
+#include "runtime/opaque_cpp.h"
+
 #include <llvm/Bitcode/BitcodeWriter.h>
 #include <llvm/IR/LLVMContext.h>
 #include <llvm/IR/Module.h>
@@ -239,12 +242,16 @@ int main(int argc, char **argv) {
     finalize_debug_info();
   }
 
-  do_bitcode_linking(*mod);
+  do_bitcode_linking(*mod, (char *)alloc_cpp_o_ll, alloc_cpp_o_ll_len);
 
   if (!no_optimize) {
     apply_kllvm_opt_passes(*mod, hidden_visibility);
   }
 
+  do_bitcode_linking(*mod, (char *)opaque_ll, opaque_ll_len);
+
+  apply_inline_pass(*mod);
+
   perform_output([&](auto &os) {
     if (emit_object) {
       generate_object_file(*mod, os);