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// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/codegen/constant-pool.h"
#include "src/codegen/assembler-inl.h"
namespace v8 {
namespace internal {
#if defined(V8_TARGET_ARCH_PPC)
ConstantPoolBuilder::ConstantPoolBuilder(int ptr_reach_bits,
int double_reach_bits) {
info_[ConstantPoolEntry::INTPTR].entries.reserve(64);
info_[ConstantPoolEntry::INTPTR].regular_reach_bits = ptr_reach_bits;
info_[ConstantPoolEntry::DOUBLE].regular_reach_bits = double_reach_bits;
}
ConstantPoolEntry::Access ConstantPoolBuilder::NextAccess(
ConstantPoolEntry::Type type) const {
const PerTypeEntryInfo& info = info_[type];
if (info.overflow()) return ConstantPoolEntry::OVERFLOWED;
int dbl_count = info_[ConstantPoolEntry::DOUBLE].regular_count;
int dbl_offset = dbl_count * kDoubleSize;
int ptr_count = info_[ConstantPoolEntry::INTPTR].regular_count;
int ptr_offset = ptr_count * kSystemPointerSize + dbl_offset;
if (type == ConstantPoolEntry::DOUBLE) {
// Double overflow detection must take into account the reach for both types
int ptr_reach_bits = info_[ConstantPoolEntry::INTPTR].regular_reach_bits;
if (!is_uintn(dbl_offset, info.regular_reach_bits) ||
(ptr_count > 0 &&
!is_uintn(ptr_offset + kDoubleSize - kSystemPointerSize,
ptr_reach_bits))) {
return ConstantPoolEntry::OVERFLOWED;
}
} else {
DCHECK(type == ConstantPoolEntry::INTPTR);
if (!is_uintn(ptr_offset, info.regular_reach_bits)) {
return ConstantPoolEntry::OVERFLOWED;
}
}
return ConstantPoolEntry::REGULAR;
}
ConstantPoolEntry::Access ConstantPoolBuilder::AddEntry(
ConstantPoolEntry& entry, ConstantPoolEntry::Type type) {
DCHECK(!emitted_label_.is_bound());
PerTypeEntryInfo& info = info_[type];
const int entry_size = ConstantPoolEntry::size(type);
bool merged = false;
if (entry.sharing_ok()) {
// Try to merge entries
std::vector<ConstantPoolEntry>::iterator it = info.shared_entries.begin();
int end = static_cast<int>(info.shared_entries.size());
for (int i = 0; i < end; i++, it++) {
if ((entry_size == kSystemPointerSize)
? entry.value() == it->value()
: entry.value64() == it->value64()) {
// Merge with found entry.
entry.set_merged_index(i);
merged = true;
break;
}
}
}
// By definition, merged entries have regular access.
DCHECK(!merged || entry.merged_index() < info.regular_count);
ConstantPoolEntry::Access access =
(merged ? ConstantPoolEntry::REGULAR : NextAccess(type));
// Enforce an upper bound on search time by limiting the search to
// unique sharable entries which fit in the regular section.
if (entry.sharing_ok() && !merged && access == ConstantPoolEntry::REGULAR) {
info.shared_entries.push_back(entry);
} else {
info.entries.push_back(entry);
}
// We're done if we found a match or have already triggered the
// overflow state.
if (merged || info.overflow()) return access;
if (access == ConstantPoolEntry::REGULAR) {
info.regular_count++;
} else {
info.overflow_start = static_cast<int>(info.entries.size()) - 1;
}
return access;
}
void ConstantPoolBuilder::EmitSharedEntries(Assembler* assm,
ConstantPoolEntry::Type type) {
PerTypeEntryInfo& info = info_[type];
std::vector<ConstantPoolEntry>& shared_entries = info.shared_entries;
const int entry_size = ConstantPoolEntry::size(type);
int base = emitted_label_.pos();
DCHECK_GT(base, 0);
int shared_end = static_cast<int>(shared_entries.size());
std::vector<ConstantPoolEntry>::iterator shared_it = shared_entries.begin();
for (int i = 0; i < shared_end; i++, shared_it++) {
int offset = assm->pc_offset() - base;
shared_it->set_offset(offset); // Save offset for merged entries.
if (entry_size == kSystemPointerSize) {
assm->dp(shared_it->value());
} else {
assm->dq(shared_it->value64());
}
DCHECK(is_uintn(offset, info.regular_reach_bits));
// Patch load sequence with correct offset.
assm->PatchConstantPoolAccessInstruction(shared_it->position(), offset,
ConstantPoolEntry::REGULAR, type);
}
}
void ConstantPoolBuilder::EmitGroup(Assembler* assm,
ConstantPoolEntry::Access access,
ConstantPoolEntry::Type type) {
PerTypeEntryInfo& info = info_[type];
const bool overflow = info.overflow();
std::vector<ConstantPoolEntry>& entries = info.entries;
std::vector<ConstantPoolEntry>& shared_entries = info.shared_entries;
const int entry_size = ConstantPoolEntry::size(type);
int base = emitted_label_.pos();
DCHECK_GT(base, 0);
int begin;
int end;
if (access == ConstantPoolEntry::REGULAR) {
// Emit any shared entries first
EmitSharedEntries(assm, type);
}
if (access == ConstantPoolEntry::REGULAR) {
begin = 0;
end = overflow ? info.overflow_start : static_cast<int>(entries.size());
} else {
DCHECK(access == ConstantPoolEntry::OVERFLOWED);
if (!overflow) return;
begin = info.overflow_start;
end = static_cast<int>(entries.size());
}
std::vector<ConstantPoolEntry>::iterator it = entries.begin();
if (begin > 0) std::advance(it, begin);
for (int i = begin; i < end; i++, it++) {
// Update constant pool if necessary and get the entry's offset.
int offset;
ConstantPoolEntry::Access entry_access;
if (!it->is_merged()) {
// Emit new entry
offset = assm->pc_offset() - base;
entry_access = access;
if (entry_size == kSystemPointerSize) {
assm->dp(it->value());
} else {
assm->dq(it->value64());
}
} else {
// Retrieve offset from shared entry.
offset = shared_entries[it->merged_index()].offset();
entry_access = ConstantPoolEntry::REGULAR;
}
DCHECK(entry_access == ConstantPoolEntry::OVERFLOWED ||
is_uintn(offset, info.regular_reach_bits));
// Patch load sequence with correct offset.
assm->PatchConstantPoolAccessInstruction(it->position(), offset,
entry_access, type);
}
}
// Emit and return size of pool.
int ConstantPoolBuilder::Emit(Assembler* assm) {
bool emitted = emitted_label_.is_bound();
bool empty = IsEmpty();
if (!emitted) {
// Mark start of constant pool. Align if necessary.
if (!empty) assm->DataAlign(kDoubleSize);
assm->bind(&emitted_label_);
if (!empty) {
// Emit in groups based on access and type.
// Emit doubles first for alignment purposes.
EmitGroup(assm, ConstantPoolEntry::REGULAR, ConstantPoolEntry::DOUBLE);
EmitGroup(assm, ConstantPoolEntry::REGULAR, ConstantPoolEntry::INTPTR);
if (info_[ConstantPoolEntry::DOUBLE].overflow()) {
assm->DataAlign(kDoubleSize);
EmitGroup(assm, ConstantPoolEntry::OVERFLOWED,
ConstantPoolEntry::DOUBLE);
}
if (info_[ConstantPoolEntry::INTPTR].overflow()) {
EmitGroup(assm, ConstantPoolEntry::OVERFLOWED,
ConstantPoolEntry::INTPTR);
}
}
}
return !empty ? (assm->pc_offset() - emitted_label_.pos()) : 0;
}
#endif // defined(V8_TARGET_ARCH_PPC)
} // namespace internal
} // namespace v8
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