Merge pull request #112 from ruby-llvm/read-write-ir

Parse and Write IR for LLVM::Module

lib/llvm/core.rb

@@ -134,6 +134,20 @@ module C
     # @return [Bool]
     # @scope class
     attach_function :is_literal_struct, :LLVMIsLiteralStruct, [:pointer], :bool
+
+    # /**
+    #  * Read LLVM IR from a memory buffer and convert it into an in-memory Module
+    #  * object. Returns 0 on success.
+    #  * Optionally returns a human-readable description of any errors that
+    #  * occurred during parsing IR. OutMessage must be disposed with
+    #  * LLVMDisposeMessage.
+    #  *
+    #  * @see llvm::ParseIR()
+    #  */
+    # LLVMBool LLVMParseIRInContext(LLVMContextRef ContextRef,
+    #                               LLVMMemoryBufferRef MemBuf, LLVMModuleRef *OutM,
+    #                               char **OutMessage);
+    attach_function :parse_ir_in_context, :LLVMParseIRInContext, [:pointer, :pointer, :pointer, :pointer], :bool
   end
 
   # Yields a pointer suitable for storing an LLVM output message.

lib/llvm/core/bitcode.rb

@@ -36,6 +36,28 @@ def write_bitcode(path_or_io)
       end
       status == 0
     end
+
+    def self.parse_ir(path_or_memory_buffer, context = Context.global)
+      memory_buffer = case path_or_memory_buffer
+      when MemoryBuffer then path_or_memory_buffer
+      else MemoryBuffer.from_file(path_or_memory_buffer)
+      end
+      FFI::MemoryPointer.new(:pointer) do |mod_ref|
+        FFI::MemoryPointer.new(:pointer) do |msg_ref|
+          status = C.parse_ir_in_context(context, memory_buffer, mod_ref, msg_ref)
+          raise msg_ref.get_pointer(0).get_string(0) if status
+          return from_ptr(mod_ref.get_pointer(0))
+        end
+      end
+    end
+
+    def write_ir!(filename)
+      FFI::MemoryPointer.new(:pointer) do |msg_ref|
+        status = C.print_module_to_file(self, filename, msg_ref)
+        raise msg_ref.get_pointer(0).get_string(0) if status != 0
+      end
+      self
+    end
   end
 
   # @private

test/bitcode_test.rb

@@ -22,5 +22,11 @@ def test_bitcode
       result = run_function_on_module(new_module, "test_function").to_i
       assert_equal 1, result
     end
+    Tempfile.open("ir") do |tmp|
+      assert test_module.write_ir!(tmp.path)
+      new_module = LLVM::Module.parse_ir(tmp.path)
+      result = run_function_on_module(new_module, "test_function").to_i
+      assert_equal 1, result
+    end
   end
 end