jdc 21-may-2010 To learn LLVM I made a wrapper got LLVM's C API. This wrapper is available at: http://github.com/jdc8/llvmtcl
The wrapper uses LLVM's C API as found in LLVM's header file Core.h in include\llvm-c.
Requirements:
There is a Makefile to build the extension;
Building a LLVM module and function:
lappend auto_path . package require llvmtcl namespace import llvmtcl::* # Initialize the JIT LLVMLinkInJIT LLVMInitializeNativeTarget # Create a module and builder set m [LLVMModuleCreateWithName "testmodule"] set bld [LLVMCreateBuilder] # Create a plus10 function, taking one argument and adding 6 and 4 to it set ft [LLVMFunctionType [LLVMInt32Type] [list [LLVMInt32Type]] 0] set plus10 [LLVMAddFunction $m "plus10" $ft] # Create constants set c6 [LLVMConstInt [LLVMInt32Type] 6 0] set c4 [LLVMConstInt [LLVMInt32Type] 4 0] # Create the basic blocks set entry [LLVMAppendBasicBlock $plus10 entry] # Put arguments on the stack to avoid having to write select and/or phi nodes LLVMPositionBuilderAtEnd $bld $entry set arg0_1 [LLVMGetParam $plus10 0] set arg0_2 [LLVMBuildAlloca $bld [LLVMInt32Type] arg0] set arg0_3 [LLVMBuildStore $bld $arg0_1 $arg0_2] # Do add 10 in two steps to see the optimizer @ work # Add 6 set arg0_4 [LLVMBuildLoad $bld $arg0_2 "arg0"] set add6 [LLVMBuildAdd $bld $arg0_4 $c6 "add6"] # Add 4 set add4 [LLVMBuildAdd $bld $add6 $c4 "add4"] # Set return LLVMBuildRet $bld $add4 # Show input puts "----- Input --------------------------------------------------" puts [LLVMDumpModule $m] # Verify the module lassign [LLVMVerifyModule $m LLVMReturnStatusAction] rt msg if {$rt} { error $msg }
This results in the following LLVM bit code:
; ModuleID = 'testmodule' define i32 @plus10(i32) { entry: %arg0 = alloca i32 ; <i32*> [#uses=2] store i32 %0, i32* %arg0 %arg01 = load i32* %arg0 ; <i32> [#uses=1] %add6 = add i32 %arg01, 6 ; <i32> [#uses=1] %add4 = add i32 %add6, 4 ; <i32> [#uses=1] ret i32 %add4 }
Now execute it:
# Execute lassign [LLVMCreateJITCompilerForModule $m 0] rt EE msg set i [LLVMCreateGenericValueOfInt [LLVMInt32Type] 4 0] set res [LLVMRunFunction $EE $plus10 $i] puts "plus10(4) = [LLVMGenericValueToInt $res 0]\n"
Now optimize the LLVM module:
# Optimize set td [LLVMCreateTargetData ""] LLVMSetDataLayout $m [LLVMCopyStringRepOfTargetData $td] LLVMOptimizeFunction $m $plus10 3 $td LLVMOptimizeModule $m 3 0 1 1 1 0 $td
Result of optimization:
; ModuleID = 'testmodule' target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64" define i32 @plus10(i32) readnone { entry: %add4 = add i32 %0, 10 ; <i32> [#uses=1] ret i32 %add4 }
The LLVM wrapper has limited support for converting Tcl into LLVM bit code and is based on the output of tcl::unsupported::disassemble. Current (stringent) limitation are:
(example still to be added)