Add wrapper over _PyLong_SMALL_INTS

Summary:
Creating a C++ API to load small PyLongObject instances.  Used in the HIR
builder and in the LIR generator.

There was the `Context::zero()` API but that's no longer used.  Remove it.

Reviewed By: yoney

Differential Revision: D113843660

fbshipit-source-id: f73bea6b6c6bf363d355fc6f4c8a60fe63feeb8a

Author: alexmalyshev

cinderx/Common/long.cpp

@@ -0,0 +1,25 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+#include "cinderx/Common/long.h"
+
+#include "cinderx/Common/log.h"
+
+extern "C" {
+
+#include "internal/pycore_long.h"
+
+} // extern "C"
+
+namespace cinderx {
+
+BorrowedRef<PyLongObject> smallInt(int32_t n) {
+  JIT_THROW_IF(
+      n < -_PY_NSMALLNEGINTS || n >= _PY_NSMALLPOSINTS,
+      "{} is out of bounds for small Python longs ([{}, {}])",
+      n,
+      -_PY_NSMALLNEGINTS,
+      _PY_NSMALLPOSINTS - 1);
+  return &_PyLong_SMALL_INTS[n + _PY_NSMALLNEGINTS];
+}
+
+} // namespace cinderx

cinderx/Common/long.h

@@ -0,0 +1,16 @@
+// Copyright (c) Meta Platforms, Inc. and affiliates.
+
+#pragma once
+
+#include "cinderx/python.h"
+
+#include "cinderx/Common/ref.h"
+
+#include <cstdint>
+
+namespace cinderx {
+
+// Load the PyLongObject for a small integer (from -5 to 256, inclusive).
+BorrowedRef<PyLongObject> smallInt(int32_t n);
+
+} // namespace cinderx

cinderx/Jit/context.cpp

@@ -122,9 +122,7 @@ std::optional<PyMethodDef*> Builtins::find(const std::string& name) const {
   return result->second;
 }
 
-Context::Context()
-    : zero_(Ref<>::steal(PyLong_FromLong(0))),
-      str_build_class_(Ref<>::create(&_Py_ID(__build_class__))) {
+Context::Context() : str_build_class_(Ref<>::create(&_Py_ID(__build_class__))) {
 #if PY_VERSION_HEX >= 0x030E0000
   for (int i = 0; i < NUM_COMMON_CONSTANTS; i++) {
     JIT_CHECK(Ci_common_consts[i] != nullptr, "common_consts[{}] is null", i);
@@ -413,10 +411,6 @@ void Context::watchType(
       type->tp_name);
 }
 
-BorrowedRef<> Context::zero() {
-  return zero_.get();
-}
-
 BorrowedRef<> Context::strBuildClass() {
   return str_build_class_.get();
 }

cinderx/Jit/context.h

@@ -453,7 +453,6 @@ class Context : public IJitContext, public CompiledFunctionOwner {
       CompilationKey& key,
       CompiledFunctionData&& compiled_func);
 
-  BorrowedRef<> zero() override;
   BorrowedRef<> strBuildClass();
 
   void watchPendingTypes();
@@ -532,7 +531,6 @@ class Context : public IJitContext, public CompiledFunctionOwner {
       std::unordered_set<TypeDeoptPatcher*>>
       type_deopt_patchers_;
 
-  Ref<> zero_;
   Ref<> str_build_class_;
   std::unordered_set<BorrowedRef<PyTypeObject>> pending_watches_;
 

cinderx/Jit/context_iface.h

@@ -17,8 +17,6 @@ class IJitContext {
 
   virtual CodeRuntime* lookupCodeRuntime(
       BorrowedRef<PyFunctionObject> func) = 0;
-
-  virtual BorrowedRef<> zero() = 0;
 };
 
 } // namespace cinderx::jit

cinderx/Jit/hir/builder.cpp

@@ -9,14 +9,14 @@
 extern "C" {
 
 #include "internal/pycore_intrinsics.h"
-#include "internal/pycore_long.h"
 #include "internal/pycore_pyerrors.h"
 #include "internal/pycore_runtime.h"
 
 } // extern "C"
 
 #include "cinderx/Common/code.h"
 #include "cinderx/Common/containers.h"
+#include "cinderx/Common/long.h"
 #include "cinderx/Common/py-portability.h"
 #include "cinderx/Common/ref.h"
 #include "cinderx/Interpreter/cinder_opcode.h"
@@ -3033,13 +3033,8 @@ void HIRBuilder::emitLoadSmallInt(
     [[maybe_unused]] const jit::BytecodeInstruction& bc_instr) {
 #if PY_VERSION_HEX >= 0x030E0000
   Register* tmp = allocateTemp();
-  JIT_CHECK(
-      bc_instr.oparg() < _PY_NSMALLPOSINTS, "LOAD_SMALL_INT out of range");
-  tc.emit<LoadConst>(
-      tmp,
-      Type::fromObject(
-          reinterpret_cast<PyObject*>(
-              &_PyLong_SMALL_INTS[_PY_NSMALLNEGINTS + bc_instr.oparg()])));
+  BorrowedRef<PyLongObject> small = smallInt(bc_instr.oparg());
+  tc.emit<LoadConst>(tmp, Type::fromObject(small.getObj()));
   tc.frame.stack.push(tmp);
 #else
   BUILDER_THROW("LOAD_SMALL_INT not supported on this Python version");

cinderx/Jit/lir/generator.cpp

@@ -25,6 +25,7 @@ extern "C" {
 
 #include "cinderx/Common/containers.h"
 #include "cinderx/Common/log.h"
+#include "cinderx/Common/long.h"
 #include "cinderx/Common/py-portability.h"
 #include "cinderx/Common/util.h"
 #include "cinderx/Interpreter/iter_helpers.h"
@@ -2779,7 +2780,9 @@ LIRGenerator::TranslatedBlock LIRGenerator::translateOneBasicBlock(
 
         // Special case for an uninitialized variable, we'll load zero.
         if (src_type == TNullptr) {
-          bbb.appendCallInstruction(output, PyLong_FromSize_t, size_t{0});
+          auto zero = reinterpret_cast<uint64_t>(smallInt(0).get());
+          bbb.appendInstr(
+              output, Instruction::kMove, Imm{zero, DataType::kObject});
           break;
         }
         if (src_type <= TCDouble) {