Welcome to Chapter 7 of the "Implementing a language with LLVM" tutorial. In chapters 1 through 6, we've built a very @@ -70,10 +70,10 @@ support for this, though the way it works is a bit unexpected for some.
To understand why mutable variables cause complexities in SSA construction, @@ -144,10 +144,10 @@ logic.
The 'trick' here is that while LLVM does require all register values to be in SSA form, it does not require (or permit) memory objects to be in SSA form. @@ -325,11 +325,10 @@ variables now!
Now that we know the sort of problem we want to tackle, lets see what this looks like in the context of our little Kaleidoscope language. We're going to @@ -382,11 +381,10 @@ Kaleidoscope to support new variable definitions.
The symbol table in Kaleidoscope is managed at code generation time by the @@ -543,7 +541,7 @@ good codegen once again:
let main () =
...
- let the_fpm = PassManager.create_function the_module_provider in
+ let the_fpm = PassManager.create_function Codegen.the_module in
(* Set up the optimizer pipeline. Start with registering info about how the
* target lays out data structures. *)
@@ -581,12 +579,12 @@ then: ; preds = %entry
else: ; preds = %entry
%x3 = load double* %x1
- %subtmp = sub double %x3, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
+ %subtmp = fsub double %x3, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
%x4 = load double* %x1
- %subtmp5 = sub double %x4, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp5 = fsub double %x4, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
br label %ifcont
ifcont: ; preds = %else, %then
@@ -619,11 +617,11 @@ then:
br label %ifcont
else:
- %subtmp = sub double %x, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
- %subtmp5 = sub double %x, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp = fsub double %x, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
+ %subtmp5 = fsub double %x, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
br label %ifcont
ifcont: ; preds = %else, %then
@@ -649,11 +647,11 @@ entry:
br i1 %ifcond, label %else, label %ifcont
else:
- %subtmp = sub double %x, 1.000000e+00
- %calltmp = call double @fib( double %subtmp )
- %subtmp5 = sub double %x, 2.000000e+00
- %calltmp6 = call double @fib( double %subtmp5 )
- %addtmp = add double %calltmp, %calltmp6
+ %subtmp = fsub double %x, 1.000000e+00
+ %calltmp = call double @fib(double %subtmp)
+ %subtmp5 = fsub double %x, 2.000000e+00
+ %calltmp6 = call double @fib(double %subtmp5)
+ %addtmp = fadd double %calltmp, %calltmp6
ret double %addtmp
ifcont:
@@ -672,10 +670,10 @@ we'll add the assignment operator.
With our current framework, adding a new assignment operator is really simple. We will parse it just like any other binary operator, but handle it @@ -773,11 +771,10 @@ add this next!
Adding var/in is just like any other other extensions we made to Kaleidoscope: we extend the lexer, the parser, the AST and the code generator. @@ -956,10 +953,10 @@ anywhere in sight.
Here is the complete code listing for our running example, enhanced with mutable @@ -999,7 +996,7 @@ ocaml_lib ~extern:true "llvm_executionengine";; ocaml_lib ~extern:true "llvm_target";; ocaml_lib ~extern:true "llvm_scalar_opts";; -flag ["link"; "ocaml"; "g++"] (S[A"-cc"; A"g++"]);; +flag ["link"; "ocaml"; "g++"] (S[A"-cc"; A"g++"; A"-cclib"; A"-rdynamic"]);; dep ["link"; "ocaml"; "use_bindings"] ["bindings.o"];; @@ -1388,6 +1385,7 @@ let context = global_context () let the_module = create_module context "my cool jit" let builder = builder context let named_values:(string, llvalue) Hashtbl.t = Hashtbl.create 10 +let double_type = double_type context (* Create an alloca instruction in the entry block of the function. This * is used for mutable variables etc. *) @@ -1482,7 +1480,7 @@ let rec codegen_expr = function let start_bb = insertion_block builder in let the_function = block_parent start_bb in - let then_bb = append_block "then" the_function in + let then_bb = append_block context "then" the_function in (* Emit 'then' value. *) position_at_end then_bb builder; @@ -1494,7 +1492,7 @@ let rec codegen_expr = function let new_then_bb = insertion_block builder in (* Emit 'else' value. *) - let else_bb = append_block "else" the_function in + let else_bb = append_block context "else" the_function in position_at_end else_bb builder; let else_val = codegen_expr else_ in @@ -1503,7 +1501,7 @@ let rec codegen_expr = function let new_else_bb = insertion_block builder in (* Emit merge block. *) - let merge_bb = append_block "ifcont" the_function in + let merge_bb = append_block context "ifcont" the_function in position_at_end merge_bb builder; let incoming = [(then_val, new_then_bb); (else_val, new_else_bb)] in let phi = build_phi incoming "iftmp" builder in @@ -1555,7 +1553,7 @@ let rec codegen_expr = function (* Make the new basic block for the loop header, inserting after current * block. *) - let loop_bb = append_block "loop" the_function in + let loop_bb = append_block context "loop" the_function in (* Insert an explicit fall through from the current block to the * loop_bb. *) @@ -1599,7 +1597,7 @@ let rec codegen_expr = function let end_cond = build_fcmp Fcmp.One end_cond zero "loopcond" builder in (* Create the "after loop" block and insert it. *) - let after_bb = append_block "afterloop" the_function in + let after_bb = append_block context "afterloop" the_function in (* Insert the conditional branch into the end of loop_end_bb. *) ignore (build_cond_br end_cond loop_bb after_bb builder); @@ -1723,7 +1721,7 @@ let codegen_func the_fpm = function end; (* Create a new basic block to start insertion into. *) - let bb = append_block "entry" the_function in + let bb = append_block context "entry" the_function in position_at_end bb builder; try @@ -1791,7 +1789,7 @@ let rec main_loop the_fpm the_execution_engine stream = the_execution_engine in print_string "Evaluated to "; - print_float (GenericValue.as_float double_type result); + print_float (GenericValue.as_float Codegen.double_type result); print_newline (); with Stream.Error s | Codegen.Error s -> (* Skip token for error recovery. *) @@ -1816,6 +1814,8 @@ open Llvm_target open Llvm_scalar_opts let main () = + ignore (initialize_native_target ()); + (* Install standard binary operators. * 1 is the lowest precedence. *) Hashtbl.add Parser.binop_precedence '=' 2; @@ -1829,9 +1829,8 @@ let main () = let stream = Lexer.lex (Stream.of_channel stdin) in (* Create the JIT. *) - let the_module_provider = ModuleProvider.create Codegen.the_module in - let the_execution_engine = ExecutionEngine.create the_module_provider in - let the_fpm = PassManager.create_function the_module_provider in + let the_execution_engine = ExecutionEngine.create Codegen.the_module in + let the_fpm = PassManager.create_function Codegen.the_module in (* Set up the optimizer pipeline. Start with registering info about how the * target lays out data structures. *) @@ -1841,7 +1840,7 @@ let main () = add_memory_to_register_promotion the_fpm; (* Do simple "peephole" optimizations and bit-twiddling optzn. *) - add_instruction_combining the_fpm; + add_instruction_combination the_fpm; (* reassociate expressions. *) add_reassociation the_fpm; @@ -1885,7 +1884,7 @@ extern double printd(double X) { -Next: Conclusion and other useful LLVM tidbits +Next: Conclusion and other useful LLVM tidbits