[Base] Make Arena alignment aware

- Add align parameter
- Templated Alloc() implicitly aligns type correctly
- Rewind may leak padding that was added due to alignment
This commit is contained in:
Joel Linn 2021-06-03 03:55:57 +02:00 committed by Rick Gibbed
parent d8cfeac79f
commit 86722be9ca
7 changed files with 43 additions and 22 deletions

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2013 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -13,6 +13,7 @@
#include <memory>
#include "xenia/base/assert.h"
#include "xenia/base/math.h"
namespace xe {
@ -45,12 +46,25 @@ void Arena::DebugFill() {
}
}
void* Arena::Alloc(size_t size) {
void* Arena::Alloc(size_t size, size_t align) {
assert_true(
xe::bit_count(align) == 1 && align <= 16,
"align needs to be a power of 2 and not greater than Chunk alignment");
// for alignment
const auto get_padding = [this, align]() -> size_t {
const size_t mask = align - 1;
size_t deviation = active_chunk_->offset & mask;
return (align - deviation) & mask;
};
if (active_chunk_) {
if (active_chunk_->capacity - active_chunk_->offset < size + 4096) {
if (active_chunk_->capacity - active_chunk_->offset <
size + get_padding() + 4096) {
Chunk* next = active_chunk_->next;
if (!next) {
assert_true(size < chunk_size_, "need to support larger chunks");
assert_true(size + get_padding() < chunk_size_,
"need to support larger chunks");
next = new Chunk(chunk_size_);
active_chunk_->next = next;
}
@ -61,8 +75,11 @@ void* Arena::Alloc(size_t size) {
head_chunk_ = active_chunk_ = new Chunk(chunk_size_);
}
active_chunk_->offset += get_padding();
uint8_t* p = active_chunk_->buffer + active_chunk_->offset;
active_chunk_->offset += size;
assert_true((reinterpret_cast<size_t>(p) & (align - 1)) == 0,
"alignment failed");
return p;
}
@ -113,6 +130,8 @@ void Arena::CloneContents(void* buffer, size_t buffer_length) {
Arena::Chunk::Chunk(size_t chunk_size)
: next(nullptr), capacity(chunk_size), buffer(0), offset(0) {
buffer = reinterpret_cast<uint8_t*>(malloc(capacity));
assert_true((reinterpret_cast<size_t>(buffer) & size_t(15)) == 0,
"16 byte alignment required");
}
Arena::Chunk::~Chunk() {

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2013 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -24,11 +24,13 @@ class Arena {
void Reset();
void DebugFill();
void* Alloc(size_t size);
void* Alloc(size_t size, size_t align);
template <typename T>
T* Alloc() {
return reinterpret_cast<T*>(Alloc(sizeof(T)));
return reinterpret_cast<T*>(Alloc(sizeof(T), alignof(T)));
}
// When rewinding aligned allocations, any padding that was applied during
// allocation will be leaked
void Rewind(size_t size);
void* CloneContents();

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2014 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -73,14 +73,14 @@ void DataFlowAnalysisPass::AnalyzeFlow(HIRBuilder* builder,
// Stash for value map. We may want to maintain this during building.
auto arena = builder->arena();
auto value_map = reinterpret_cast<Value**>(
arena->Alloc(sizeof(Value*) * max_value_estimate));
arena->Alloc(sizeof(Value*) * max_value_estimate, alignof(Value)));
// Allocate incoming bitvectors for use by blocks. We don't need outgoing
// because they are only used during the block iteration.
// Mapped by block ordinal.
// TODO(benvanik): cache this list, grow as needed, etc.
auto incoming_bitvectors =
(llvm::BitVector**)arena->Alloc(sizeof(llvm::BitVector*) * block_count);
auto incoming_bitvectors = (llvm::BitVector**)arena->Alloc(
sizeof(llvm::BitVector*) * block_count, alignof(llvm::BitVector));
for (auto n = 0u; n < block_count; n++) {
incoming_bitvectors[n] = new llvm::BitVector(max_value_estimate);
}

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2020 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -45,7 +45,7 @@ bool FinalizationPass::Run(HIRBuilder* builder) {
while (label) {
if (!label->name) {
const size_t label_len = 6 + 4;
char* name = reinterpret_cast<char*>(arena->Alloc(label_len + 1));
char* name = reinterpret_cast<char*>(arena->Alloc(label_len + 1, 1));
assert_true(label->id <= 9999);
auto end = fmt::format_to_n(name, label_len, "_label{}", label->id);
name[end.size] = '\0';

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2020 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -739,7 +739,7 @@ void HIRBuilder::Comment(std::string_view value) {
return;
}
auto size = value.size();
auto p = reinterpret_cast<char*>(arena_->Alloc(size + 1));
auto p = reinterpret_cast<char*>(arena_->Alloc(size + 1, 1));
std::memcpy(p, value.data(), size);
p[size] = '\0';
Instr* i = AppendInstr(OPCODE_COMMENT_info, 0);
@ -752,7 +752,7 @@ void HIRBuilder::Comment(const StringBuffer& value) {
return;
}
auto size = value.length();
auto p = reinterpret_cast<char*>(arena_->Alloc(size + 1));
auto p = reinterpret_cast<char*>(arena_->Alloc(size + 1, 1));
std::memcpy(p, value.buffer(), size);
p[size] = '\0';
Instr* i = AppendInstr(OPCODE_COMMENT_info, 0);

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2020 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -75,7 +75,7 @@ class HIRBuilder {
template <typename... Args>
void CommentFormat(const std::string_view format, const Args&... args) {
static const uint32_t kMaxCommentSize = 1024;
char* p = reinterpret_cast<char*>(arena_->Alloc(kMaxCommentSize));
char* p = reinterpret_cast<char*>(arena_->Alloc(kMaxCommentSize, 1));
auto result = fmt::format_to_n(p, kMaxCommentSize - 1, format, args...);
p[result.size] = '\0';
size_t rewind = kMaxCommentSize - 1 - result.size;

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@ -2,7 +2,7 @@
******************************************************************************
* Xenia : Xbox 360 Emulator Research Project *
******************************************************************************
* Copyright 2020 Ben Vanik. All rights reserved. *
* Copyright 2021 Ben Vanik. All rights reserved. *
* Released under the BSD license - see LICENSE in the root for more details. *
******************************************************************************
*/
@ -104,8 +104,8 @@ bool PPCHIRBuilder::Emit(GuestFunction* function, uint32_t flags) {
// instruction may have a label assigned to it if it hasn't been hit
// yet.
size_t list_size = instr_count_ * sizeof(void*);
instr_offset_list_ = (Instr**)arena_->Alloc(list_size);
label_list_ = (Label**)arena_->Alloc(list_size);
instr_offset_list_ = (Instr**)arena_->Alloc(list_size, alignof(void*));
label_list_ = (Label**)arena_->Alloc(list_size, alignof(void*));
std::memset(instr_offset_list_, 0, list_size);
std::memset(label_list_, 0, list_size);
@ -244,7 +244,7 @@ void PPCHIRBuilder::AnnotateLabel(uint32_t address, Label* label) {
char name_buffer[13];
auto format_result = fmt::format_to_n(name_buffer, 12, "loc_{:08X}", address);
name_buffer[format_result.size] = '\0';
label->name = (char*)arena_->Alloc(sizeof(name_buffer));
label->name = (char*)arena_->Alloc(sizeof(name_buffer), 1);
memcpy(label->name, name_buffer, sizeof(name_buffer));
}