gccrs: Support some LLVM builtin functions

gcc/rust/backend/rust-builtins.cc

@@ -29,6 +29,10 @@ BuiltinsContext &
 BuiltinsContext::get ()
 {
   static BuiltinsContext instance;
+
+  if (instance.setup_state == SetupState::UNINITIALIZED)
+    instance.setup ();
+
   return instance;
 }
 
@@ -44,7 +48,26 @@ BuiltinsContext::lookup_simple_builtin (const std::string &name, tree *builtin)
   return lookup_gcc_builtin (*to_search, builtin);
 }
 
-BuiltinsContext::BuiltinsContext () { setup (); }
+LlvmBuiltinMappingResult
+BuiltinsContext::map_llvm_to_gcc_builtin (const std::string &name,
+					  tree *resolved,
+					  LlvmBuiltinAdapter *adapter)
+{
+  rust_assert (resolved != nullptr);
+
+  auto mapping = llvm_to_gcc_builtin.find (name);
+  if (mapping == llvm_to_gcc_builtin.end ())
+    return LlvmBuiltinMappingResult::NOT_MAPPED;
+
+  *resolved = NULL_TREE;
+  if (!lookup_gcc_builtin (mapping->second.gcc_name, resolved))
+    return LlvmBuiltinMappingResult::TARGET_UNAVAILABLE;
+
+  *adapter = mapping->second.adapter;
+  return LlvmBuiltinMappingResult::RESOLVED;
+}
+
+BuiltinsContext::BuiltinsContext () : setup_state (SetupState::UNINITIALIZED) {}
 
 /**
  * Define a function type according to `builtin-types.def`
@@ -355,14 +378,83 @@ BuiltinsContext::register_rust_mappings ()
   };
 }
 
+void
+BuiltinsContext::register_llvm_to_gcc_builtin ()
+{
+  llvm_to_gcc_builtin = {
+    {"llvm.x86.rdrand.16",
+     {"__builtin_ia32_rdrand16_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+    {"llvm.x86.rdrand.32",
+     {"__builtin_ia32_rdrand32_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+    {"llvm.x86.rdrand.64",
+     {"__builtin_ia32_rdrand64_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+    {"llvm.x86.rdseed.16",
+     {"__builtin_ia32_rdseed_hi_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+    {"llvm.x86.rdseed.32",
+     {"__builtin_ia32_rdseed_si_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+    {"llvm.x86.rdseed.64",
+     {"__builtin_ia32_rdseed_di_step",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_VALUE_STATUS}},
+
+    {"llvm.x86.addcarry.32",
+     {"__builtin_ia32_addcarryx_u32",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_STATUS_VALUE}},
+    {"llvm.x86.addcarryx.u32",
+     {"__builtin_ia32_addcarryx_u32", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+    {"llvm.x86.subborrow.32",
+     {"__builtin_ia32_sbb_u32",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_STATUS_VALUE}},
+    {"llvm.x86.addcarry.64",
+     {"__builtin_ia32_addcarryx_u64",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_STATUS_VALUE}},
+    {"llvm.x86.addcarryx.u64",
+     {"__builtin_ia32_addcarryx_u64", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+    {"llvm.x86.subborrow.64",
+     {"__builtin_ia32_sbb_u64",
+      LlvmBuiltinAdapter::OUTPUT_POINTER_STATUS_VALUE}},
+
+    {"llvm.x86.vcvtph2ps.128",
+     {"__builtin_ia32_vcvtph2ps", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+    {"llvm.x86.vcvtph2ps.256",
+     {"__builtin_ia32_vcvtph2ps256", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+    {"llvm.x86.vcvtps2ph.128",
+     {"__builtin_ia32_vcvtps2ph", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+    {"llvm.x86.vcvtps2ph.256",
+     {"__builtin_ia32_vcvtps2ph256", LlvmBuiltinAdapter::FORWARD_ARGUMENTS}},
+  };
+}
+
+void
+BuiltinsContext::register_builtin (tree decl)
+{
+  rust_assert (TREE_CODE (decl) == FUNCTION_DECL);
+  rust_assert (DECL_NAME (decl));
+
+  const char *name = IDENTIFIER_POINTER (DECL_NAME (decl));
+  builtin_functions.insert ({std::string (name), decl});
+}
+
 void
 BuiltinsContext::setup ()
 {
+  rust_assert (setup_state == SetupState::UNINITIALIZED);
+  setup_state = SetupState::INITIALIZING;
+
   define_builtin_types ();
   define_builtin_attributes ();
   define_builtins ();
 
+  targetm.init_builtins ();
+
   register_rust_mappings ();
+  register_llvm_to_gcc_builtin ();
+
+  setup_state = SetupState::READY;
 }
 
 bool

gcc/rust/backend/rust-builtins.h

@@ -79,13 +79,39 @@ namespace Compile {
 // };
 // Some(cx.get_intrinsic(&llvm_name))
 
+enum class LlvmBuiltinMappingResult
+{
+  NOT_MAPPED,
+  TARGET_UNAVAILABLE,
+  RESOLVED,
+};
+
+enum class LlvmBuiltinAdapter
+{
+  OUTPUT_POINTER_VALUE_STATUS,
+  OUTPUT_POINTER_STATUS_VALUE,
+  FORWARD_ARGUMENTS,
+};
+
+struct LlvmBuiltinMapping
+{
+  std::string gcc_name;
+  LlvmBuiltinAdapter adapter;
+};
+
 class BuiltinsContext
 {
 public:
   static BuiltinsContext &get ();
 
   bool lookup_simple_builtin (const std::string &name, tree *builtin);
 
+  LlvmBuiltinMappingResult
+  map_llvm_to_gcc_builtin (const std::string &name, tree *resolved,
+			   LlvmBuiltinAdapter *adapter);
+
+  void register_builtin (tree decl);
+
 private:
   enum Type
   {
@@ -166,6 +192,15 @@ class BuiltinsContext
     ATTR_LAST,
   };
 
+  enum class SetupState
+  {
+    UNINITIALIZED,
+    INITIALIZING,
+    READY,
+  };
+
+  SetupState setup_state;
+
   /**
    * All builtin types, as defined in `builtin-types.def`
    *
@@ -190,6 +225,7 @@ class BuiltinsContext
   void define_builtins ();
 
   void register_rust_mappings ();
+  void register_llvm_to_gcc_builtin ();
 
   BuiltinsContext ();
 
@@ -204,6 +240,7 @@ class BuiltinsContext
   // A mapping of the GCC built-ins exposed to GCC Rust.
   std::map<std::string, tree> builtin_functions;
   std::map<std::string, std::string> rust_intrinsic_to_gcc_builtin;
+  std::map<std::string, LlvmBuiltinMapping> llvm_to_gcc_builtin;
 };
 
 } // namespace Compile