468 lines
13 KiB
C++
468 lines
13 KiB
C++
//===-- BrainF.cpp - BrainF compiler example ----------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===--------------------------------------------------------------------===//
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//
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// This class compiles the BrainF language into LLVM assembly.
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//
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// The BrainF language has 8 commands:
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// Command Equivalent C Action
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// ------- ------------ ------
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// , *h=getchar(); Read a character from stdin, 255 on EOF
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// . putchar(*h); Write a character to stdout
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// - --*h; Decrement tape
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// + ++*h; Increment tape
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// < --h; Move head left
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// > ++h; Move head right
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// [ while(*h) { Start loop
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// ] } End loop
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//
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//===--------------------------------------------------------------------===//
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#include "BrainF.h"
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/Intrinsics.h"
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#include "llvm/ADT/STLExtras.h"
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#include <iostream>
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using namespace llvm;
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//Set the constants for naming
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const char *BrainF::tapereg = "tape";
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const char *BrainF::headreg = "head";
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const char *BrainF::label = "brainf";
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const char *BrainF::testreg = "test";
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Module *BrainF::parse(std::istream *in1, int mem, CompileFlags cf,
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LLVMContext& Context) {
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in = in1;
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memtotal = mem;
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comflag = cf;
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header(Context);
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readloop(0, 0, 0, Context);
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delete builder;
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return module;
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}
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void BrainF::header(LLVMContext& C) {
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module = new Module("BrainF", C);
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//Function prototypes
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//declare void @llvm.memset.p0i8.i32(i8 *, i8, i32, i32, i1)
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Type *Tys[] = { Type::getInt8PtrTy(C), Type::getInt32Ty(C) };
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Function *memset_func = Intrinsic::getDeclaration(module, Intrinsic::memset,
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Tys);
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//declare i32 @getchar()
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getchar_func = cast<Function>(module->
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getOrInsertFunction("getchar", IntegerType::getInt32Ty(C), NULL));
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//declare i32 @putchar(i32)
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putchar_func = cast<Function>(module->
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getOrInsertFunction("putchar", IntegerType::getInt32Ty(C),
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IntegerType::getInt32Ty(C), NULL));
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//Function header
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//define void @brainf()
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brainf_func = cast<Function>(module->
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getOrInsertFunction("brainf", Type::getVoidTy(C), NULL));
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builder = new IRBuilder<>(BasicBlock::Create(C, label, brainf_func));
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//%arr = malloc i8, i32 %d
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ConstantInt *val_mem = ConstantInt::get(C, APInt(32, memtotal));
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BasicBlock* BB = builder->GetInsertBlock();
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Type* IntPtrTy = IntegerType::getInt32Ty(C);
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Type* Int8Ty = IntegerType::getInt8Ty(C);
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Constant* allocsize = ConstantExpr::getSizeOf(Int8Ty);
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allocsize = ConstantExpr::getTruncOrBitCast(allocsize, IntPtrTy);
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ptr_arr = CallInst::CreateMalloc(BB, IntPtrTy, Int8Ty, allocsize, val_mem,
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NULL, "arr");
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BB->getInstList().push_back(cast<Instruction>(ptr_arr));
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//call void @llvm.memset.p0i8.i32(i8 *%arr, i8 0, i32 %d, i32 1, i1 0)
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{
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Value *memset_params[] = {
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ptr_arr,
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ConstantInt::get(C, APInt(8, 0)),
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val_mem,
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ConstantInt::get(C, APInt(32, 1)),
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ConstantInt::get(C, APInt(1, 0))
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};
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CallInst *memset_call = builder->
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CreateCall(memset_func, memset_params);
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memset_call->setTailCall(false);
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}
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//%arrmax = getelementptr i8 *%arr, i32 %d
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if (comflag & flag_arraybounds) {
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ptr_arrmax = builder->
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CreateGEP(ptr_arr, ConstantInt::get(C, APInt(32, memtotal)), "arrmax");
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}
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//%head.%d = getelementptr i8 *%arr, i32 %d
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curhead = builder->CreateGEP(ptr_arr,
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ConstantInt::get(C, APInt(32, memtotal/2)),
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headreg);
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//Function footer
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//brainf.end:
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endbb = BasicBlock::Create(C, label, brainf_func);
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//call free(i8 *%arr)
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endbb->getInstList().push_back(CallInst::CreateFree(ptr_arr, endbb));
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//ret void
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ReturnInst::Create(C, endbb);
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//Error block for array out of bounds
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if (comflag & flag_arraybounds)
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{
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//@aberrormsg = internal constant [%d x i8] c"\00"
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Constant *msg_0 =
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ConstantDataArray::getString(C, "Error: The head has left the tape.",
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true);
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GlobalVariable *aberrormsg = new GlobalVariable(
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*module,
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msg_0->getType(),
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true,
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GlobalValue::InternalLinkage,
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msg_0,
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"aberrormsg");
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//declare i32 @puts(i8 *)
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Function *puts_func = cast<Function>(module->
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getOrInsertFunction("puts", IntegerType::getInt32Ty(C),
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PointerType::getUnqual(IntegerType::getInt8Ty(C)), NULL));
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//brainf.aberror:
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aberrorbb = BasicBlock::Create(C, label, brainf_func);
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//call i32 @puts(i8 *getelementptr([%d x i8] *@aberrormsg, i32 0, i32 0))
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{
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Constant *zero_32 = Constant::getNullValue(IntegerType::getInt32Ty(C));
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Constant *gep_params[] = {
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zero_32,
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zero_32
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};
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Constant *msgptr = ConstantExpr::
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getGetElementPtr(aberrormsg, gep_params);
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Value *puts_params[] = {
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msgptr
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};
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CallInst *puts_call =
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CallInst::Create(puts_func,
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puts_params,
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"", aberrorbb);
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puts_call->setTailCall(false);
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}
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//br label %brainf.end
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BranchInst::Create(endbb, aberrorbb);
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}
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}
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void BrainF::readloop(PHINode *phi, BasicBlock *oldbb, BasicBlock *testbb,
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LLVMContext &C) {
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Symbol cursym = SYM_NONE;
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int curvalue = 0;
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Symbol nextsym = SYM_NONE;
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int nextvalue = 0;
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char c;
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int loop;
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int direction;
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while(cursym != SYM_EOF && cursym != SYM_ENDLOOP) {
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// Write out commands
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switch(cursym) {
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case SYM_NONE:
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// Do nothing
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break;
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case SYM_READ:
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{
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//%tape.%d = call i32 @getchar()
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CallInst *getchar_call = builder->CreateCall(getchar_func, tapereg);
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getchar_call->setTailCall(false);
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Value *tape_0 = getchar_call;
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//%tape.%d = trunc i32 %tape.%d to i8
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Value *tape_1 = builder->
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CreateTrunc(tape_0, IntegerType::getInt8Ty(C), tapereg);
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//store i8 %tape.%d, i8 *%head.%d
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builder->CreateStore(tape_1, curhead);
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}
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break;
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case SYM_WRITE:
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{
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//%tape.%d = load i8 *%head.%d
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LoadInst *tape_0 = builder->CreateLoad(curhead, tapereg);
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//%tape.%d = sext i8 %tape.%d to i32
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Value *tape_1 = builder->
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CreateSExt(tape_0, IntegerType::getInt32Ty(C), tapereg);
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//call i32 @putchar(i32 %tape.%d)
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Value *putchar_params[] = {
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tape_1
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};
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CallInst *putchar_call = builder->
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CreateCall(putchar_func,
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putchar_params);
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putchar_call->setTailCall(false);
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}
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break;
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case SYM_MOVE:
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{
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//%head.%d = getelementptr i8 *%head.%d, i32 %d
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curhead = builder->
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CreateGEP(curhead, ConstantInt::get(C, APInt(32, curvalue)),
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headreg);
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//Error block for array out of bounds
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if (comflag & flag_arraybounds)
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{
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//%test.%d = icmp uge i8 *%head.%d, %arrmax
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Value *test_0 = builder->
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CreateICmpUGE(curhead, ptr_arrmax, testreg);
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//%test.%d = icmp ult i8 *%head.%d, %arr
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Value *test_1 = builder->
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CreateICmpULT(curhead, ptr_arr, testreg);
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//%test.%d = or i1 %test.%d, %test.%d
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Value *test_2 = builder->
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CreateOr(test_0, test_1, testreg);
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//br i1 %test.%d, label %main.%d, label %main.%d
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BasicBlock *nextbb = BasicBlock::Create(C, label, brainf_func);
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builder->CreateCondBr(test_2, aberrorbb, nextbb);
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//main.%d:
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builder->SetInsertPoint(nextbb);
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}
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}
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break;
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case SYM_CHANGE:
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{
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//%tape.%d = load i8 *%head.%d
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LoadInst *tape_0 = builder->CreateLoad(curhead, tapereg);
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//%tape.%d = add i8 %tape.%d, %d
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Value *tape_1 = builder->
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CreateAdd(tape_0, ConstantInt::get(C, APInt(8, curvalue)), tapereg);
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//store i8 %tape.%d, i8 *%head.%d\n"
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builder->CreateStore(tape_1, curhead);
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}
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break;
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case SYM_LOOP:
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{
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//br label %main.%d
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BasicBlock *testbb = BasicBlock::Create(C, label, brainf_func);
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builder->CreateBr(testbb);
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//main.%d:
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BasicBlock *bb_0 = builder->GetInsertBlock();
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BasicBlock *bb_1 = BasicBlock::Create(C, label, brainf_func);
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builder->SetInsertPoint(bb_1);
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// Make part of PHI instruction now, wait until end of loop to finish
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PHINode *phi_0 =
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PHINode::Create(PointerType::getUnqual(IntegerType::getInt8Ty(C)),
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2, headreg, testbb);
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phi_0->addIncoming(curhead, bb_0);
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curhead = phi_0;
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readloop(phi_0, bb_1, testbb, C);
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}
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break;
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default:
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std::cerr << "Error: Unknown symbol.\n";
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abort();
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break;
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}
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cursym = nextsym;
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curvalue = nextvalue;
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nextsym = SYM_NONE;
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// Reading stdin loop
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loop = (cursym == SYM_NONE)
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|| (cursym == SYM_MOVE)
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|| (cursym == SYM_CHANGE);
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while(loop) {
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*in>>c;
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if (in->eof()) {
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if (cursym == SYM_NONE) {
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cursym = SYM_EOF;
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} else {
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nextsym = SYM_EOF;
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}
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loop = 0;
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} else {
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direction = 1;
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switch(c) {
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case '-':
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direction = -1;
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// Fall through
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case '+':
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if (cursym == SYM_CHANGE) {
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curvalue += direction;
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// loop = 1
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} else {
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if (cursym == SYM_NONE) {
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cursym = SYM_CHANGE;
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curvalue = direction;
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// loop = 1
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} else {
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nextsym = SYM_CHANGE;
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nextvalue = direction;
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loop = 0;
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}
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}
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break;
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case '<':
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direction = -1;
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// Fall through
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case '>':
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if (cursym == SYM_MOVE) {
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curvalue += direction;
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// loop = 1
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} else {
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if (cursym == SYM_NONE) {
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cursym = SYM_MOVE;
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curvalue = direction;
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// loop = 1
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} else {
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nextsym = SYM_MOVE;
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nextvalue = direction;
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loop = 0;
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}
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}
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break;
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case ',':
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if (cursym == SYM_NONE) {
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cursym = SYM_READ;
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} else {
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nextsym = SYM_READ;
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}
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loop = 0;
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break;
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case '.':
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if (cursym == SYM_NONE) {
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cursym = SYM_WRITE;
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} else {
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nextsym = SYM_WRITE;
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}
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loop = 0;
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break;
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case '[':
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if (cursym == SYM_NONE) {
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cursym = SYM_LOOP;
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} else {
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nextsym = SYM_LOOP;
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}
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loop = 0;
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break;
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case ']':
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if (cursym == SYM_NONE) {
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cursym = SYM_ENDLOOP;
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} else {
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nextsym = SYM_ENDLOOP;
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}
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loop = 0;
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break;
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// Ignore other characters
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default:
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break;
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}
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}
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}
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}
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if (cursym == SYM_ENDLOOP) {
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if (!phi) {
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std::cerr << "Error: Extra ']'\n";
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abort();
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}
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// Write loop test
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{
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//br label %main.%d
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builder->CreateBr(testbb);
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//main.%d:
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//%head.%d = phi i8 *[%head.%d, %main.%d], [%head.%d, %main.%d]
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//Finish phi made at beginning of loop
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phi->addIncoming(curhead, builder->GetInsertBlock());
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Value *head_0 = phi;
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//%tape.%d = load i8 *%head.%d
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LoadInst *tape_0 = new LoadInst(head_0, tapereg, testbb);
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//%test.%d = icmp eq i8 %tape.%d, 0
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ICmpInst *test_0 = new ICmpInst(*testbb, ICmpInst::ICMP_EQ, tape_0,
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ConstantInt::get(C, APInt(8, 0)), testreg);
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//br i1 %test.%d, label %main.%d, label %main.%d
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BasicBlock *bb_0 = BasicBlock::Create(C, label, brainf_func);
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BranchInst::Create(bb_0, oldbb, test_0, testbb);
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//main.%d:
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builder->SetInsertPoint(bb_0);
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//%head.%d = phi i8 *[%head.%d, %main.%d]
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PHINode *phi_1 = builder->
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CreatePHI(PointerType::getUnqual(IntegerType::getInt8Ty(C)), 1,
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headreg);
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phi_1->addIncoming(head_0, testbb);
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curhead = phi_1;
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}
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return;
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}
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//End of the program, so go to return block
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builder->CreateBr(endbb);
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if (phi) {
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std::cerr << "Error: Missing ']'\n";
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abort();
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}
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}
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