source: icGREP/icgrep-devel/icgrep/kernels/scanmatchgen.cpp @ 5098

Last change on this file since 5098 was 5096, checked in by cameron, 3 years ago

Simplify kernel DoBlock? interface

File size: 13.3 KB
Line 
1/*
2 *  Copyright (c) 2015 International Characters.
3 *  This software is licensed to the public under the Open Software License 3.0.
4 */
5
6#include "kernel.h"
7#include "scanmatchgen.h"
8#include <llvm/IR/Intrinsics.h>
9#include <IDISA/idisa_builder.h>
10#include <llvm/Support/raw_os_ostream.h>
11
12using namespace llvm;
13
14namespace kernel {
15
16Value * generateForwardZeroesMask(IDISA::IDISA_Builder * iBuilder, Value * bits) {
17    Value * bits_minus1 = iBuilder->CreateSub(bits, ConstantInt::get(bits->getType(), 1));
18    return iBuilder->CreateAnd(bits_minus1, iBuilder->CreateNot(bits));
19}
20
21Value * generatePopcount(IDISA::IDISA_Builder * iBuilder, Value * bits) {
22    Value * ctpopFunc = Intrinsic::getDeclaration(iBuilder->getModule(), Intrinsic::ctpop, bits->getType());
23    return iBuilder->CreateCall(ctpopFunc, std::vector<Value *>({bits}));
24}
25
26Value * generateCountForwardZeroes(IDISA::IDISA_Builder * iBuilder, Value * bits) {
27    Value * cttzFunc = Intrinsic::getDeclaration(iBuilder->getModule(), Intrinsic::cttz, bits->getType());
28    return iBuilder->CreateCall(cttzFunc, std::vector<Value *>({bits, ConstantInt::get(iBuilder->getInt1Ty(), 0)}));
29}
30
31Value * generateCountReverseZeroes(IDISA::IDISA_Builder * iBuilder, Value * bits) {
32    Value * ctlzFunc = Intrinsic::getDeclaration(iBuilder->getModule(), Intrinsic::ctlz, bits->getType());
33    return iBuilder->CreateCall(ctlzFunc, std::vector<Value *>({bits, ConstantInt::get(iBuilder->getInt1Ty(), 0)}));
34}
35
36Value * generateResetLowestBit(IDISA::IDISA_Builder * iBuilder, Value * bits) {
37    Value * bits_minus1 = iBuilder->CreateSub(bits, ConstantInt::get(bits->getType(), 1));
38    return iBuilder->CreateAnd(bits_minus1, bits);
39}
40
41       
42void scanMatchKernel::generateDoBlockMethod() {
43    IDISA::IDISA_Builder::InsertPoint savePoint = iBuilder->saveIP();
44    Module * m = iBuilder->getModule();
45    Function * scanWordFunction = generateScanWordRoutine(m);
46    const unsigned fieldCount = iBuilder->getBitBlockWidth() / mScanwordBitWidth;
47    Type * T = iBuilder->getIntNTy(mScanwordBitWidth);
48    Type * scanwordVectorType =  VectorType::get(T, fieldCount);
49
50    Function * doBlockFunction = m->getFunction(mKernelName + doBlock_suffix);
51
52    iBuilder->SetInsertPoint(BasicBlock::Create(iBuilder->getContext(), "entry", doBlockFunction, 0));
53    Value * kernelStuctParam = getParameter(doBlockFunction, "self");
54    Value * blockNo = getScalarField(kernelStuctParam, blockNoScalar);
55    Value * scanwordPos = iBuilder->CreateMul(blockNo, ConstantInt::get(blockNo->getType(), iBuilder->getBitBlockWidth()));
56   
57    Value * recordStart = getScalarField(kernelStuctParam, "LineStart");
58    Value * recordNum = getScalarField(kernelStuctParam, "LineNum");
59   
60    Value * matchResultsPtr = getCircularBufferBlockPointer(kernelStuctParam, "matchResults", blockNo);
61   
62    Value * matches = iBuilder->CreateBlockAlignedLoad(matchResultsPtr, {iBuilder->getInt32(0), iBuilder->getInt32(0)});
63    Value * linebreaks = iBuilder->CreateBlockAlignedLoad(matchResultsPtr, {iBuilder->getInt32(0), iBuilder->getInt32(1)});
64    Value * matchWordVector = iBuilder->CreateBitCast(matches, scanwordVectorType);
65    Value * breakWordVector = iBuilder->CreateBitCast(linebreaks, scanwordVectorType);
66    for(unsigned i = 0; i < fieldCount; ++i){
67        Value * matchWord = iBuilder->CreateExtractElement(matchWordVector, ConstantInt::get(T, i));
68        Value * recordBreaksWord = iBuilder->CreateExtractElement(breakWordVector, ConstantInt::get(T, i));
69        Value * wordResult = iBuilder->CreateCall(scanWordFunction, {kernelStuctParam, matchWord, recordBreaksWord, scanwordPos, recordStart, recordNum});
70        scanwordPos = iBuilder->CreateAdd(scanwordPos, ConstantInt::get(T, mScanwordBitWidth));
71        recordStart = iBuilder->CreateExtractValue(wordResult, std::vector<unsigned>({0}));
72        recordNum = iBuilder->CreateExtractValue(wordResult, std::vector<unsigned>({1}));
73    }
74    setScalarField(kernelStuctParam, "LineStart", recordStart);
75    setScalarField(kernelStuctParam, "LineNum", recordNum);
76    iBuilder -> CreateRetVoid();
77    iBuilder->restoreIP(savePoint);
78}
79
80   
81Function * scanMatchKernel::generateScanWordRoutine(Module * m) {
82    Function * function = m->getFunction("scan_matches_in_scanword");
83    if (LLVM_UNLIKELY(function != nullptr)) {
84        return function;
85    }
86   
87    LLVMContext & ctxt = m->getContext();
88    Type * T = iBuilder->getIntNTy(mScanwordBitWidth);
89    Type * S = PointerType::get(iBuilder->getIntNTy(8), 0);
90    Type * returnType = StructType::get(ctxt, std::vector<Type *>({T, T}));
91    FunctionType * functionType = FunctionType::get(returnType, std::vector<Type *>({PointerType::get(mKernelStateType, 0), T, T, T, T, T}), false);
92   
93    SmallVector<AttributeSet, 6> Attrs;
94    Attrs.push_back(AttributeSet::get(ctxt, ~0U, std::vector<Attribute::AttrKind>({ Attribute::NoUnwind, Attribute::UWTable })));
95    Attrs.push_back(AttributeSet::get(ctxt, 1, std::vector<Attribute::AttrKind>({})));
96    Attrs.push_back(AttributeSet::get(ctxt, 2, std::vector<Attribute::AttrKind>({})));
97    Attrs.push_back(AttributeSet::get(ctxt, 3, std::vector<Attribute::AttrKind>({})));
98    Attrs.push_back(AttributeSet::get(ctxt, 4, std::vector<Attribute::AttrKind>({})));
99    Attrs.push_back(AttributeSet::get(ctxt, 5, std::vector<Attribute::AttrKind>({})));
100    AttributeSet AttrSet = AttributeSet::get(ctxt, Attrs);
101   
102    function = Function::Create(functionType, GlobalValue::ExternalLinkage, "scan_matches_in_scanword", m);
103    function->setCallingConv(CallingConv::C);
104    function->setAttributes(AttrSet);
105    function->addFnAttr(llvm::Attribute::AlwaysInline);
106   
107    Function::arg_iterator args = function->arg_begin();
108    Value * instance = &*(args++);
109    instance->setName("this");
110    Value * matches_input_parm = &*(args++);
111    matches_input_parm->setName("matches");
112    Value * record_breaks_input_parm = &*(args++);
113    record_breaks_input_parm->setName("breaks");
114    Value * scanwordPos = &*(args++);
115    scanwordPos->setName("scanwordPos");
116    Value * recordStart_input_parm = &*(args++);
117    recordStart_input_parm->setName("pendingLineStart");
118    Value * recordNum_input_parm = &*(args++);
119    recordNum_input_parm->setName("lineNum");
120   
121    Constant * matchProcessor;
122    if (mIsNameExpression) {
123        matchProcessor = m->getOrInsertFunction("insert_codepoints", Type::getVoidTy(ctxt), T, T, T, S, nullptr);
124    } else {
125        matchProcessor = m->getOrInsertFunction("wrapped_report_match", Type::getVoidTy(ctxt), T, T, T, S, T, T, nullptr);
126    }
127    iBuilder->SetInsertPoint(BasicBlock::Create(ctxt, "entry", function,0));
128   
129    BasicBlock * entry_block = iBuilder->GetInsertBlock();
130    BasicBlock * matches_test_block = BasicBlock::Create(ctxt, "matches_test_block", function, 0);
131    BasicBlock * process_matches_loop_entry = BasicBlock::Create(ctxt, "process_matches_loop", function, 0);
132    BasicBlock * prior_breaks_block = BasicBlock::Create(ctxt, "prior_breaks_block", function, 0);
133    BasicBlock * loop_final_block = BasicBlock::Create(ctxt, "loop_final_block", function, 0);
134    BasicBlock * matches_done_block = BasicBlock::Create(ctxt, "matches_done_block", function, 0);
135    BasicBlock * remaining_breaks_block = BasicBlock::Create(ctxt, "remaining_breaks_block", function, 0);
136    BasicBlock * return_block = BasicBlock::Create(ctxt, "return_block", function, 0);
137   
138   
139    // The match scanner works with a loop involving four variables:
140    // (a) the bit stream scanword of matches marking the ends of selected records,
141    // (b) the bit stream scanword of record_breaks marking the ends of all records,
142    // (c) the integer lastRecordNum indicating the number of records processed so far,
143    // (d) the index lastRecordStart indicating the file position of the last record.
144    // We set up a loop structure, in which a set of 4 phi nodes initialize these
145    // variables from either the input to the scanner or the computed values within
146    // the loop body.
147   
148   
149    iBuilder->CreateBr(matches_test_block);
150   
151    // LOOP Test Block
152    iBuilder->SetInsertPoint(matches_test_block);
153    PHINode * matches_phi = iBuilder->CreatePHI(T, 2, "matches");
154    PHINode * record_breaks_phi = iBuilder->CreatePHI(T, 2, "record_breaks");
155    PHINode * recordNum_phi = iBuilder->CreatePHI(T, 2, "recordNum");
156    PHINode * recordStart_phi = iBuilder->CreatePHI(T, 2, "recordStart");
157    matches_phi->addIncoming(matches_input_parm, entry_block);
158    record_breaks_phi->addIncoming(record_breaks_input_parm, entry_block);
159    recordNum_phi->addIncoming(recordNum_input_parm, entry_block);
160    recordStart_phi->addIncoming(recordStart_input_parm, entry_block);
161    Value * have_matches_cond = iBuilder->CreateICmpNE(matches_phi, ConstantInt::get(T, 0));
162    iBuilder->CreateCondBr(have_matches_cond, process_matches_loop_entry, matches_done_block);
163   
164    // LOOP BODY
165    // The loop body is entered if we have more matches to process.
166    iBuilder->SetInsertPoint(process_matches_loop_entry);
167    Value * prior_breaks = iBuilder->CreateAnd(generateForwardZeroesMask(iBuilder, matches_phi), record_breaks_phi);
168    // Within the loop we have a conditional block that is executed if there are any prior
169    // record breaks.
170    Value * prior_breaks_cond = iBuilder->CreateICmpNE(prior_breaks, ConstantInt::get(T, 0));
171    iBuilder->CreateCondBr(prior_breaks_cond, prior_breaks_block, loop_final_block);
172   
173    // PRIOR_BREAKS_BLOCK
174    // If there are prior breaks, we count them and compute the record start position.
175    iBuilder->SetInsertPoint(prior_breaks_block);
176    Value * matchRecordNum = iBuilder->CreateAdd(generatePopcount(iBuilder, prior_breaks), recordNum_phi);
177    Value * reverseDistance = generateCountReverseZeroes(iBuilder, prior_breaks);
178    Value * width = ConstantInt::get(T, mScanwordBitWidth);
179    Value * matchRecordStart = iBuilder->CreateAdd(scanwordPos, iBuilder->CreateSub(width, reverseDistance));
180    iBuilder->CreateBr(loop_final_block);
181   
182    // LOOP FINAL BLOCK
183    // The prior breaks, if any have been counted.  Set up phi nodes for the recordNum
184    // and recortStart depending on whether the conditional execution of prior_breaks_block.
185    iBuilder->SetInsertPoint(loop_final_block);
186    PHINode * matchRecordNum_phi = iBuilder->CreatePHI(T, 2, "matchRecordNum");
187    PHINode * matchRecordStart_phi = iBuilder->CreatePHI(T, 2, "matchRecordStart");
188    matchRecordNum_phi->addIncoming(recordNum_phi, process_matches_loop_entry);
189    matchRecordNum_phi->addIncoming(matchRecordNum, prior_breaks_block);
190    matchRecordStart_phi->addIncoming(recordStart_phi, process_matches_loop_entry);
191    matchRecordStart_phi->addIncoming(matchRecordStart, prior_breaks_block);   
192    Value * matchRecordEnd = iBuilder->CreateAdd(scanwordPos, generateCountForwardZeroes(iBuilder, matches_phi));
193   
194
195    Value * fileBuf = getScalarField(instance, "FileBuf");
196    if (mIsNameExpression) {
197        iBuilder->CreateCall(matchProcessor, std::vector<Value *>({matchRecordNum_phi, matchRecordStart_phi, matchRecordEnd, fileBuf}));
198    } else {
199        Value * fileSize = getScalarField(instance, "FileSize");
200        Value * fileIdx = getScalarField(instance, "FileIdx");
201        iBuilder->CreateCall(matchProcessor, std::vector<Value *>({matchRecordNum_phi, matchRecordStart_phi, matchRecordEnd, fileBuf, fileSize, fileIdx}));
202    }
203   
204    Value * remaining_matches = generateResetLowestBit(iBuilder, matches_phi);
205    Value * remaining_breaks = iBuilder->CreateXor(record_breaks_phi, prior_breaks);
206    matches_phi->addIncoming(remaining_matches, loop_final_block);
207    record_breaks_phi->addIncoming(remaining_breaks, loop_final_block);
208    recordNum_phi->addIncoming(matchRecordNum_phi, loop_final_block);
209    recordStart_phi->addIncoming(matchRecordStart_phi, loop_final_block);
210    iBuilder->CreateBr(matches_test_block);
211   
212   
213    // LOOP EXIT/MATCHES_DONE
214    iBuilder->SetInsertPoint(matches_done_block);
215    // When the matches are done, there may be additional record breaks remaining
216    Value * more_breaks_cond = iBuilder->CreateICmpNE(record_breaks_phi, ConstantInt::get(T, 0));
217    iBuilder->CreateCondBr(more_breaks_cond, remaining_breaks_block, return_block);
218   
219    // REMAINING_BREAKS_BLOCK: process remaining record breaks after all matches are processed
220    iBuilder->SetInsertPoint(remaining_breaks_block);
221    Value * break_count = generatePopcount(iBuilder, record_breaks_phi);
222    Value * final_record_num = iBuilder->CreateAdd(recordNum_phi, break_count);
223    Value * reverseZeroes = generateCountReverseZeroes(iBuilder, record_breaks_phi);
224    Value * pendingLineStart = iBuilder->CreateAdd(scanwordPos, iBuilder->CreateSub(width, reverseZeroes));
225    iBuilder->CreateBr(return_block);
226   
227    // RETURN block
228    iBuilder->SetInsertPoint(return_block);
229    PHINode * finalRecordCount_phi = iBuilder->CreatePHI(T, 2, "finalRecordCount");
230    PHINode * finalRecordStart_phi = iBuilder->CreatePHI(T, 2, "finalRecordStart");
231    finalRecordCount_phi->addIncoming(recordNum_phi, matches_done_block);
232    finalRecordCount_phi->addIncoming(final_record_num, remaining_breaks_block);
233    finalRecordStart_phi->addIncoming(recordStart_phi, matches_done_block);
234    finalRecordStart_phi->addIncoming(pendingLineStart, remaining_breaks_block);
235    Value * retVal = UndefValue::get(returnType);
236    retVal = iBuilder->CreateInsertValue(retVal, finalRecordStart_phi, 0);
237    retVal = iBuilder->CreateInsertValue(retVal, finalRecordCount_phi, 1);
238    iBuilder->CreateRet(retVal);
239   
240    return function;
241}
242
243}
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