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doris/be/src/exec/hash_table.cpp
EmmyMiao87 b187c0881c Fix bug of null safe equal join (#2193)
2019-11-14 08:52:48 +08:00

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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
#include "exec/hash_table.hpp"
#include "codegen/codegen_anyval.h"
#include "codegen/llvm_codegen.h"
#include "exprs/expr.h"
#include "runtime/raw_value.h"
#include "runtime/string_value.hpp"
#include "runtime/mem_tracker.h"
#include "runtime/runtime_state.h"
#include "util/doris_metrics.h"
using llvm::BasicBlock;
using llvm::Value;
using llvm::Function;
using llvm::Type;
using llvm::PointerType;
using llvm::LLVMContext;
using llvm::PHINode;
namespace doris {
const float HashTable::MAX_BUCKET_OCCUPANCY_FRACTION = 0.75f;
const char* HashTable::_s_llvm_class_name = "class.doris::HashTable";
HashTable::HashTable(const vector<ExprContext*>& build_expr_ctxs,
const vector<ExprContext*>& probe_expr_ctxs,
int num_build_tuples, bool stores_nulls,
const std::vector<bool>& finds_nulls,
int32_t initial_seed,
MemTracker* mem_tracker, int64_t num_buckets) :
_build_expr_ctxs(build_expr_ctxs),
_probe_expr_ctxs(probe_expr_ctxs),
_num_build_tuples(num_build_tuples),
_stores_nulls(stores_nulls),
_finds_nulls(finds_nulls),
_initial_seed(initial_seed),
_node_byte_size(sizeof(Node) + sizeof(Tuple*) * _num_build_tuples),
_num_filled_buckets(0),
_nodes(NULL),
_num_nodes(0),
_exceeded_limit(false),
_mem_tracker(mem_tracker),
_mem_limit_exceeded(false) {
DCHECK(mem_tracker != NULL);
DCHECK_EQ(_build_expr_ctxs.size(), _probe_expr_ctxs.size());
DCHECK_EQ((num_buckets & (num_buckets - 1)), 0) << "num_buckets must be a power of 2";
_buckets.resize(num_buckets);
_num_buckets = num_buckets;
_num_buckets_till_resize = MAX_BUCKET_OCCUPANCY_FRACTION * _num_buckets;
_mem_tracker->consume(_buckets.capacity() * sizeof(Bucket));
// Compute the layout and buffer size to store the evaluated expr results
_results_buffer_size = Expr::compute_results_layout(_build_expr_ctxs,
&_expr_values_buffer_offsets, &_var_result_begin);
_expr_values_buffer = new uint8_t[_results_buffer_size];
memset(_expr_values_buffer, 0, sizeof(uint8_t) * _results_buffer_size);
_expr_value_null_bits = new uint8_t[_build_expr_ctxs.size()];
_nodes_capacity = 1024;
_nodes = reinterpret_cast<uint8_t*>(malloc(_nodes_capacity * _node_byte_size));
memset(_nodes, 0, _nodes_capacity * _node_byte_size);
#if 0
if (DorisMetrics::hash_table_total_bytes() != NULL) {
DorisMetrics::hash_table_total_bytes()->increment(_nodes_capacity * _node_byte_size);
}
#endif
_mem_tracker->consume(_nodes_capacity * _node_byte_size);
if (_mem_tracker->limit_exceeded()) {
mem_limit_exceeded(_nodes_capacity * _node_byte_size);
}
}
HashTable::~HashTable() {
}
void HashTable::close() {
// TODO: use tr1::array?
delete[] _expr_values_buffer;
delete[] _expr_value_null_bits;
free(_nodes);
#if 0
if (DorisMetrics::hash_table_total_bytes() != NULL) {
DorisMetrics::hash_table_total_bytes()->increment(-_nodes_capacity * _node_byte_size);
}
#endif
_mem_tracker->release(_nodes_capacity * _node_byte_size);
_mem_tracker->release(_buckets.size() * sizeof(Bucket));
}
bool HashTable::eval_row(TupleRow* row, const vector<ExprContext*>& ctxs) {
// Put a non-zero constant in the result location for NULL.
// We don't want(NULL, 1) to hash to the same as (0, 1).
// This needs to be as big as the biggest primitive type since the bytes
// get copied directly.
// the 10 is experience value which need bigger than sizeof(Decimal)/sizeof(int64).
// for if slot is null, we need copy the null value to all type.
static int64_t null_value[10] = {HashUtil::FNV_SEED, HashUtil::FNV_SEED, 0};
bool has_null = false;
for (int i = 0; i < ctxs.size(); ++i) {
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
void* val = ctxs[i]->get_value(row);
if (val == NULL) {
// If the table doesn't store nulls, no reason to keep evaluating
if (!_stores_nulls) {
return true;
}
_expr_value_null_bits[i] = true;
val = &null_value;
has_null = true;
} else {
_expr_value_null_bits[i] = false;
}
RawValue::write(val, loc, _build_expr_ctxs[i]->root()->type(), NULL);
}
return has_null;
}
uint32_t HashTable::hash_variable_len_row() {
uint32_t hash = _initial_seed;
// Hash the non-var length portions (if there are any)
if (_var_result_begin != 0) {
hash = HashUtil::hash(_expr_values_buffer, _var_result_begin, hash);
}
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
// non-string and null slots are already part of expr_values_buffer
if (_build_expr_ctxs[i]->root()->type().is_string_type()) {
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
if (_expr_value_null_bits[i]) {
// Hash the null random seed values at 'loc'
hash = HashUtil::hash(loc, sizeof(StringValue), hash);
} else {
// Hash the string
StringValue* str = reinterpret_cast<StringValue*>(loc);
hash = HashUtil::hash(str->ptr, str->len, hash);
}
} else if (_build_expr_ctxs[i]->root()->type().type == TYPE_DECIMAL) {
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
if (_expr_value_null_bits[i]) {
// Hash the null random seed values at 'loc'
hash = HashUtil::hash(loc, sizeof(StringValue), hash);
} else {
DecimalValue* decimal = reinterpret_cast<DecimalValue*>(loc);
hash = decimal->hash(hash);
}
}
}
return hash;
}
bool HashTable::equals(TupleRow* build_row) {
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
void* val = _build_expr_ctxs[i]->get_value(build_row);
if (val == NULL) {
if (!(_stores_nulls && _finds_nulls[i])) {
return false;
}
if (!_expr_value_null_bits[i]) {
return false;
}
continue;
}
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
if (!RawValue::eq(loc, val, _build_expr_ctxs[i]->root()->type())) {
return false;
}
}
return true;
}
void HashTable::resize_buckets(int64_t num_buckets) {
DCHECK_EQ((num_buckets & (num_buckets - 1)), 0) << "num_buckets must be a power of 2";
int64_t old_num_buckets = _num_buckets;
int64_t delta_bytes = (num_buckets - old_num_buckets) * sizeof(Bucket);
if (!_mem_tracker->try_consume(delta_bytes)) {
mem_limit_exceeded(delta_bytes);
return;
}
_buckets.resize(num_buckets);
// If we're doubling the number of buckets, all nodes in a particular bucket
// either remain there, or move down to an analogous bucket in the other half.
// In order to efficiently check which of the two buckets a node belongs in, the number
// of buckets must be a power of 2.
bool doubled_buckets = (num_buckets == old_num_buckets * 2);
for (int i = 0; i < _num_buckets; ++i) {
Bucket* bucket = &_buckets[i];
Bucket* sister_bucket = &_buckets[i + old_num_buckets];
Node* last_node = NULL;
int node_idx = bucket->_node_idx;
while (node_idx != -1) {
Node* node = get_node(node_idx);
int64_t next_idx = node->_next_idx;
uint32_t hash = node->_hash;
bool node_must_move = true;
Bucket* move_to = NULL;
if (doubled_buckets) {
node_must_move = ((hash & old_num_buckets) != 0);
move_to = sister_bucket;
} else {
int64_t bucket_idx = hash & (num_buckets - 1);
node_must_move = (bucket_idx != i);
move_to = &_buckets[bucket_idx];
}
if (node_must_move) {
move_node(bucket, move_to, node_idx, node, last_node);
} else {
last_node = node;
}
node_idx = next_idx;
}
}
_num_buckets = num_buckets;
_num_buckets_till_resize = MAX_BUCKET_OCCUPANCY_FRACTION * _num_buckets;
}
void HashTable::grow_node_array() {
int64_t old_size = _nodes_capacity * _node_byte_size;
_nodes_capacity = _nodes_capacity + _nodes_capacity / 2;
int64_t new_size = _nodes_capacity * _node_byte_size;
uint8_t* new_nodes = reinterpret_cast<uint8_t*>(malloc(new_size));
memset(new_nodes, 0, new_size);
memcpy(new_nodes, _nodes, old_size);
free(_nodes);
_nodes = new_nodes;
#if 0
if (DorisMetrics::hash_table_total_bytes() != NULL) {
DorisMetrics::hash_table_total_bytes()->increment(new_size - old_size);
}
#endif
_mem_tracker->consume(new_size - old_size);
if (_mem_tracker->limit_exceeded()) {
mem_limit_exceeded(new_size - old_size);
}
}
void HashTable::mem_limit_exceeded(int64_t allocation_size) {
_mem_limit_exceeded = true;
_exceeded_limit = true;
// if (_state != NULL) {
// _state->set_mem_limit_exceeded(_mem_tracker, allocation_size);
// }
}
std::string HashTable::debug_string(bool skip_empty, const RowDescriptor* desc) {
std::stringstream ss;
ss << std::endl;
for (int i = 0; i < _buckets.size(); ++i) {
int64_t node_idx = _buckets[i]._node_idx;
bool first = true;
if (skip_empty && node_idx == -1) {
continue;
}
ss << i << ": ";
while (node_idx != -1) {
Node* node = get_node(node_idx);
if (!first) {
ss << ",";
}
if (desc == NULL) {
ss << node_idx << "(" << (void*)node->data() << ")";
} else {
ss << (void*)node->data() << " " << node->data()->to_string(*desc);
}
node_idx = node->_next_idx;
first = false;
}
ss << std::endl;
}
return ss.str();
}
// Helper function to store a value into the results buffer if the expr
// evaluated to NULL. We don't want (NULL, 1) to hash to the same as (0,1) so
// we'll pick a more random value.
static void codegen_assign_null_value(
LlvmCodeGen* codegen, LlvmCodeGen::LlvmBuilder* builder,
Value* dst, const TypeDescriptor& type) {
int64_t fvn_seed = HashUtil::FNV_SEED;
if (type.type == TYPE_CHAR || type.type == TYPE_VARCHAR) {
Value* dst_ptr = builder->CreateStructGEP(dst, 0, "string_ptr");
Value* dst_len = builder->CreateStructGEP(dst, 1, "string_len");
Value* null_len = codegen->get_int_constant(TYPE_INT, fvn_seed);
Value* null_ptr = builder->CreateIntToPtr(null_len, codegen->ptr_type());
builder->CreateStore(null_ptr, dst_ptr);
builder->CreateStore(null_len, dst_len);
return;
} else {
Value* null_value = NULL;
// Get a type specific representation of fvn_seed
switch (type.type) {
case TYPE_BOOLEAN:
// In results, booleans are stored as 1 byte
dst = builder->CreateBitCast(dst, codegen->ptr_type());
null_value = codegen->get_int_constant(TYPE_TINYINT, fvn_seed);
break;
case TYPE_TINYINT:
case TYPE_SMALLINT:
case TYPE_INT:
case TYPE_BIGINT:
null_value = codegen->get_int_constant(type.type, fvn_seed);
break;
case TYPE_FLOAT: {
// Don't care about the value, just the bit pattern
float fvn_seed_float = *reinterpret_cast<float*>(&fvn_seed);
null_value = llvm::ConstantFP::get(
codegen->context(), llvm::APFloat(fvn_seed_float));
break;
}
case TYPE_DOUBLE: {
// Don't care about the value, just the bit pattern
double fvn_seed_double = *reinterpret_cast<double*>(&fvn_seed);
null_value = llvm::ConstantFP::get(
codegen->context(), llvm::APFloat(fvn_seed_double));
break;
}
default:
DCHECK(false);
}
builder->CreateStore(null_value, dst);
}
}
// Codegen for evaluating a tuple row over either _build_expr_ctxs or _probe_expr_ctxs.
// For the case where we are joining on a single int, the IR looks like
// define i1 @EvaBuildRow(%"class.impala::HashTable"* %this_ptr,
// %"class.impala::TupleRow"* %row) {
// entry:
// %null_ptr = alloca i1
// %0 = bitcast %"class.doris::TupleRow"* %row to i8**
// %eval = call i32 @SlotRef(i8** %0, i8* null, i1* %null_ptr)
// %1 = load i1* %null_ptr
// br i1 %1, label %null, label %not_null
//
// null: ; preds = %entry
// ret i1 true
//
// not_null: ; preds = %entry
// store i32 %eval, i32* inttoptr (i64 46146336 to i32*)
// br label %continue
//
// continue: ; preds = %not_null
// %2 = zext i1 %1 to i8
// store i8 %2, i8* inttoptr (i64 46146248 to i8*)
// ret i1 false
// }
// For each expr, we create 3 code blocks. The null, not null and continue blocks.
// Both the null and not null branch into the continue block. The continue block
// becomes the start of the next block for codegen (either the next expr or just the
// end of the function).
Function* HashTable::codegen_eval_tuple_row(RuntimeState* state, bool build) {
// TODO: codegen_assign_null_value() can't handle TYPE_TIMESTAMP or TYPE_DECIMAL yet
const std::vector<ExprContext*>& ctxs = build ? _build_expr_ctxs : _probe_expr_ctxs;
for (int i = 0; i < ctxs.size(); ++i) {
PrimitiveType type = ctxs[i]->root()->type().type;
if (type == TYPE_DATE || type == TYPE_DATETIME
|| type == TYPE_DECIMAL || type == TYPE_CHAR || type == TYPE_DECIMALV2) {
return NULL;
}
}
LlvmCodeGen* codegen = NULL;
if (!state->get_codegen(&codegen).ok()) {
return NULL;
}
// Get types to generate function prototype
Type* tuple_row_type = codegen->get_type(TupleRow::_s_llvm_class_name);
DCHECK(tuple_row_type != NULL);
PointerType* tuple_row_ptr_type = PointerType::get(tuple_row_type, 0);
Type* this_type = codegen->get_type(HashTable::_s_llvm_class_name);
DCHECK(this_type != NULL);
PointerType* this_ptr_type = PointerType::get(this_type, 0);
LlvmCodeGen::FnPrototype prototype(
codegen, build ? "eval_build_row" : "eval_probe_row", codegen->get_type(TYPE_BOOLEAN));
prototype.add_argument(LlvmCodeGen::NamedVariable("this_ptr", this_ptr_type));
prototype.add_argument(LlvmCodeGen::NamedVariable("row", tuple_row_ptr_type));
LLVMContext& context = codegen->context();
LlvmCodeGen::LlvmBuilder builder(context);
Value* args[2];
Function* fn = prototype.generate_prototype(&builder, args);
Value* row = args[1];
Value* has_null = codegen->false_value();
// Aggregation with no grouping exprs also use the hash table interface for
// code simplicity. In that case, there are no build exprs.
if (!_build_expr_ctxs.empty()) {
const std::vector<ExprContext*>& ctxs = build ? _build_expr_ctxs : _probe_expr_ctxs;
for (int i = 0; i < ctxs.size(); ++i) {
// TODO: refactor this to somewhere else? This is not hash table specific
// except for the null handling bit and would be used for anyone that needs
// to materialize a vector of exprs
// Convert result buffer to llvm ptr type
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
Value* llvm_loc = codegen->cast_ptr_to_llvm_ptr(
codegen->get_ptr_type(ctxs[i]->root()->type()), loc);
BasicBlock* null_block = BasicBlock::Create(context, "null", fn);
BasicBlock* not_null_block = BasicBlock::Create(context, "not_null", fn);
BasicBlock* continue_block = BasicBlock::Create(context, "continue", fn);
// Call expr
Function* expr_fn = NULL;
Status status = ctxs[i]->root()->get_codegend_compute_fn(state, &expr_fn);
if (!status.ok()) {
std::stringstream ss;
ss << "Problem with codegen: " << status.get_error_msg();
// TODO(zc )
// state->LogError(ErrorMsg(TErrorCode::GENERAL, ss.str()));
fn->eraseFromParent(); // deletes function
return NULL;
}
Value* ctx_arg = codegen->cast_ptr_to_llvm_ptr(
codegen->get_ptr_type(ExprContext::_s_llvm_class_name), ctxs[i]);
Value* expr_fn_args[] = { ctx_arg, row };
CodegenAnyVal result = CodegenAnyVal::create_call_wrapped(
codegen, &builder, ctxs[i]->root()->type(),
expr_fn, expr_fn_args, "result", NULL);
Value* is_null = result.get_is_null();
// Set null-byte result
Value* null_byte = builder.CreateZExt(is_null, codegen->get_type(TYPE_TINYINT));
uint8_t* null_byte_loc = &_expr_value_null_bits[i];
Value* llvm_null_byte_loc =
codegen->cast_ptr_to_llvm_ptr(codegen->ptr_type(), null_byte_loc);
builder.CreateStore(null_byte, llvm_null_byte_loc);
builder.CreateCondBr(is_null, null_block, not_null_block);
// Null block
builder.SetInsertPoint(null_block);
if (!_stores_nulls) {
// hash table doesn't store nulls, no reason to keep evaluating exprs
builder.CreateRet(codegen->true_value());
} else {
codegen_assign_null_value(codegen, &builder, llvm_loc, ctxs[i]->root()->type());
has_null = codegen->true_value();
builder.CreateBr(continue_block);
}
// Not null block
builder.SetInsertPoint(not_null_block);
result.to_native_ptr(llvm_loc);
builder.CreateBr(continue_block);
builder.SetInsertPoint(continue_block);
}
}
builder.CreateRet(has_null);
return codegen->finalize_function(fn);
}
// Codegen for hashing the current row. In the case with both string and non-string data
// (group by int_col, string_col), the IR looks like:
// define i32 @hash_current_row(%"class.impala::HashTable"* %this_ptr) {
// entry:
// %0 = call i32 @IrCrcHash(i8* inttoptr (i64 51107808 to i8*), i32 16, i32 0)
// %1 = load i8* inttoptr (i64 29500112 to i8*)
// %2 = icmp ne i8 %1, 0
// br i1 %2, label %null, label %not_null
//
// null: ; preds = %entry
// %3 = call i32 @IrCrcHash(i8* inttoptr (i64 51107824 to i8*), i32 16, i32 %0)
// br label %continue
//
// not_null: ; preds = %entry
// %4 = load i8** getelementptr inbounds (
// %"struct.impala::StringValue"* inttoptr
// (i64 51107824 to %"struct.impala::StringValue"*), i32 0, i32 0)
// %5 = load i32* getelementptr inbounds (
// %"struct.impala::StringValue"* inttoptr
// (i64 51107824 to %"struct.impala::StringValue"*), i32 0, i32 1)
// %6 = call i32 @IrCrcHash(i8* %4, i32 %5, i32 %0)
// br label %continue
//
// continue: ; preds = %not_null, %null
// %7 = phi i32 [ %6, %not_null ], [ %3, %null ]
// ret i32 %7
// }
// TODO: can this be cross-compiled?
Function* HashTable::codegen_hash_current_row(RuntimeState* state) {
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
// Disable codegen for CHAR
if (_build_expr_ctxs[i]->root()->type().type == TYPE_CHAR) {
return NULL;
}
}
LlvmCodeGen* codegen = NULL;
if (!state->get_codegen(&codegen).ok()) {
return NULL;
}
// Get types to generate function prototype
Type* this_type = codegen->get_type(HashTable::_s_llvm_class_name);
DCHECK(this_type != NULL);
PointerType* this_ptr_type = PointerType::get(this_type, 0);
LlvmCodeGen::FnPrototype prototype(codegen, "hash_current_row", codegen->get_type(TYPE_INT));
prototype.add_argument(LlvmCodeGen::NamedVariable("this_ptr", this_ptr_type));
LLVMContext& context = codegen->context();
LlvmCodeGen::LlvmBuilder builder(context);
Value* this_arg = NULL;
Function* fn = prototype.generate_prototype(&builder, &this_arg);
Value* hash_result = codegen->get_int_constant(TYPE_INT, _initial_seed);
Value* data = codegen->cast_ptr_to_llvm_ptr(codegen->ptr_type(), _expr_values_buffer);
if (_var_result_begin == -1) {
// No variable length slots, just hash what is in '_expr_values_buffer'
if (_results_buffer_size > 0) {
Function* hash_fn = codegen->get_hash_function(_results_buffer_size);
Value* len = codegen->get_int_constant(TYPE_INT, _results_buffer_size);
hash_result = builder.CreateCall3(hash_fn, data, len, hash_result);
}
} else {
if (_var_result_begin > 0) {
Function* hash_fn = codegen->get_hash_function(_var_result_begin);
Value* len = codegen->get_int_constant(TYPE_INT, _var_result_begin);
hash_result = builder.CreateCall3(hash_fn, data, len, hash_result);
}
// Hash string slots
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
if (_build_expr_ctxs[i]->root()->type().type != TYPE_CHAR
&& _build_expr_ctxs[i]->root()->type().type != TYPE_VARCHAR) {
continue;
}
BasicBlock* null_block = NULL;
BasicBlock* not_null_block = NULL;
BasicBlock* continue_block = NULL;
Value* str_null_result = NULL;
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
// If the hash table stores nulls, we need to check if the stringval
// evaluated to NULL
if (_stores_nulls) {
null_block = BasicBlock::Create(context, "null", fn);
not_null_block = BasicBlock::Create(context, "not_null", fn);
continue_block = BasicBlock::Create(context, "continue", fn);
uint8_t* null_byte_loc = &_expr_value_null_bits[i];
Value* llvm_null_byte_loc =
codegen->cast_ptr_to_llvm_ptr(codegen->ptr_type(), null_byte_loc);
Value* null_byte = builder.CreateLoad(llvm_null_byte_loc);
Value* is_null = builder.CreateICmpNE(
null_byte, codegen->get_int_constant(TYPE_TINYINT, 0));
builder.CreateCondBr(is_null, null_block, not_null_block);
// For null, we just want to call the hash function on the portion of
// the data
builder.SetInsertPoint(null_block);
Function* null_hash_fn = codegen->get_hash_function(sizeof(StringValue));
Value* llvm_loc = codegen->cast_ptr_to_llvm_ptr(codegen->ptr_type(), loc);
Value* len = codegen->get_int_constant(TYPE_INT, sizeof(StringValue));
str_null_result = builder.CreateCall3(null_hash_fn, llvm_loc, len, hash_result);
builder.CreateBr(continue_block);
builder.SetInsertPoint(not_null_block);
}
// Convert _expr_values_buffer loc to llvm value
Value* str_val = codegen->cast_ptr_to_llvm_ptr(
codegen->get_ptr_type(TYPE_VARCHAR), loc);
Value* ptr = builder.CreateStructGEP(str_val, 0, "ptr");
Value* len = builder.CreateStructGEP(str_val, 1, "len");
ptr = builder.CreateLoad(ptr);
len = builder.CreateLoad(len);
// Call hash(ptr, len, hash_result);
Function* general_hash_fn = codegen->get_hash_function();
Value* string_hash_result =
builder.CreateCall3(general_hash_fn, ptr, len, hash_result);
if (_stores_nulls) {
builder.CreateBr(continue_block);
builder.SetInsertPoint(continue_block);
// Use phi node to reconcile that we could have come from the string-null
// path and string not null paths.
PHINode* phi_node = builder.CreatePHI(codegen->get_type(TYPE_INT), 2);
phi_node->addIncoming(string_hash_result, not_null_block);
phi_node->addIncoming(str_null_result, null_block);
hash_result = phi_node;
} else {
hash_result = string_hash_result;
}
}
}
builder.CreateRet(hash_result);
return codegen->finalize_function(fn);
}
// Codegen for HashTable::Equals. For a hash table with two exprs (string,int), the
// IR looks like:
//
// define i1 @Equals(%"class.impala::OldHashTable"* %this_ptr,
// %"class.impala::TupleRow"* %row) {
// entry:
// %result = call i64 @get_slot_ref(%"class.impala::ExprContext"* inttoptr
// (i64 146381856 to %"class.impala::ExprContext"*),
// %"class.impala::TupleRow"* %row)
// %0 = trunc i64 %result to i1
// br i1 %0, label %null, label %not_null
//
// false_block: ; preds = %not_null2, %null1, %not_null, %null
// ret i1 false
//
// null: ; preds = %entry
// br i1 false, label %continue, label %false_block
//
// not_null: ; preds = %entry
// %1 = load i32* inttoptr (i64 104774368 to i32*)
// %2 = ashr i64 %result, 32
// %3 = trunc i64 %2 to i32
// %cmp_raw = icmp eq i32 %3, %1
// br i1 %cmp_raw, label %continue, label %false_block
//
// continue: ; preds = %not_null, %null
// %result4 = call { i64, i8* } @get_slot_ref(
// %"class.impala::ExprContext"* inttoptr
// (i64 146381696 to %"class.impala::ExprContext"*),
// %"class.impala::TupleRow"* %row)
// %4 = extractvalue { i64, i8* } %result4, 0
// %5 = trunc i64 %4 to i1
// br i1 %5, label %null1, label %not_null2
//
// null1: ; preds = %continue
// br i1 false, label %continue3, label %false_block
//
// not_null2: ; preds = %continue
// %6 = extractvalue { i64, i8* } %result4, 0
// %7 = ashr i64 %6, 32
// %8 = trunc i64 %7 to i32
// %result5 = extractvalue { i64, i8* } %result4, 1
// %cmp_raw6 = call i1 @_Z11StringValEQPciPKN6impala11StringValueE(
// i8* %result5, i32 %8, %"struct.impala::StringValue"* inttoptr
// (i64 104774384 to %"struct.impala::StringValue"*))
// br i1 %cmp_raw6, label %continue3, label %false_block
//
// continue3: ; preds = %not_null2, %null1
// ret i1 true
// }
Function* HashTable::codegen_equals(RuntimeState* state) {
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
// Disable codegen for CHAR
if (_build_expr_ctxs[i]->root()->type().type == TYPE_CHAR) {
return NULL;
}
}
LlvmCodeGen* codegen = NULL;
if (!state->get_codegen(&codegen).ok()) {
return NULL;
}
// Get types to generate function prototype
Type* tuple_row_type = codegen->get_type(TupleRow::_s_llvm_class_name);
DCHECK(tuple_row_type != NULL);
PointerType* tuple_row_ptr_type = PointerType::get(tuple_row_type, 0);
Type* this_type = codegen->get_type(HashTable::_s_llvm_class_name);
DCHECK(this_type != NULL);
PointerType* this_ptr_type = PointerType::get(this_type, 0);
LlvmCodeGen::FnPrototype prototype(codegen, "equals", codegen->get_type(TYPE_BOOLEAN));
prototype.add_argument(LlvmCodeGen::NamedVariable("this_ptr", this_ptr_type));
prototype.add_argument(LlvmCodeGen::NamedVariable("row", tuple_row_ptr_type));
LLVMContext& context = codegen->context();
LlvmCodeGen::LlvmBuilder builder(context);
Value* args[2];
Function* fn = prototype.generate_prototype(&builder, args);
Value* row = args[1];
if (!_build_expr_ctxs.empty()) {
BasicBlock* false_block = BasicBlock::Create(context, "false_block", fn);
for (int i = 0; i < _build_expr_ctxs.size(); ++i) {
BasicBlock* null_block = BasicBlock::Create(context, "null", fn);
BasicBlock* not_null_block = BasicBlock::Create(context, "not_null", fn);
BasicBlock* continue_block = BasicBlock::Create(context, "continue", fn);
// call GetValue on build_exprs[i]
Function* expr_fn = NULL;
Status status = _build_expr_ctxs[i]->root()->get_codegend_compute_fn(state, &expr_fn);
if (!status.ok()) {
std::stringstream ss;
ss << "Problem with codegen: " << status.get_error_msg();
// TODO(zc)
// state->LogError(ErrorMsg(TErrorCode::GENERAL, ss.str()));
fn->eraseFromParent(); // deletes function
return NULL;
}
Value* ctx_arg = codegen->cast_ptr_to_llvm_ptr(
codegen->get_ptr_type(ExprContext::_s_llvm_class_name), _build_expr_ctxs[i]);
Value* expr_fn_args[] = { ctx_arg, row };
CodegenAnyVal result = CodegenAnyVal::create_call_wrapped(
codegen, &builder, _build_expr_ctxs[i]->root()->type(),
expr_fn, expr_fn_args, "result", NULL);
Value* is_null = result.get_is_null();
// Determine if probe is null (i.e. _expr_value_null_bits[i] == true). In
// the case where the hash table does not store nulls, this is always false.
Value* probe_is_null = codegen->false_value();
uint8_t* null_byte_loc = &_expr_value_null_bits[i];
if (_stores_nulls) {
Value* llvm_null_byte_loc =
codegen->cast_ptr_to_llvm_ptr(codegen->ptr_type(), null_byte_loc);
Value* null_byte = builder.CreateLoad(llvm_null_byte_loc);
probe_is_null = builder.CreateICmpNE(
null_byte, codegen->get_int_constant(TYPE_TINYINT, 0));
}
// Get llvm value for probe_val from '_expr_values_buffer'
void* loc = _expr_values_buffer + _expr_values_buffer_offsets[i];
Value* probe_val = codegen->cast_ptr_to_llvm_ptr(
codegen->get_ptr_type(_build_expr_ctxs[i]->root()->type()), loc);
// Branch for GetValue() returning NULL
builder.CreateCondBr(is_null, null_block, not_null_block);
// Null block
builder.SetInsertPoint(null_block);
builder.CreateCondBr(probe_is_null, continue_block, false_block);
// Not-null block
builder.SetInsertPoint(not_null_block);
if (_stores_nulls) {
BasicBlock* cmp_block = BasicBlock::Create(context, "cmp", fn);
// First need to compare that probe expr[i] is not null
builder.CreateCondBr(probe_is_null, false_block, cmp_block);
builder.SetInsertPoint(cmp_block);
}
// Check result == probe_val
Value* is_equal = result.eq_to_native_ptr(probe_val);
builder.CreateCondBr(is_equal, continue_block, false_block);
builder.SetInsertPoint(continue_block);
}
builder.CreateRet(codegen->true_value());
builder.SetInsertPoint(false_block);
builder.CreateRet(codegen->false_value());
} else {
builder.CreateRet(codegen->true_value());
}
return codegen->finalize_function(fn);
}
}
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