summaryrefslogtreecommitdiff
path: root/compiler/utils/arm/assembler_thumb2.cc
diff options
context:
space:
mode:
Diffstat (limited to 'compiler/utils/arm/assembler_thumb2.cc')
-rw-r--r--compiler/utils/arm/assembler_thumb2.cc206
1 files changed, 203 insertions, 3 deletions
diff --git a/compiler/utils/arm/assembler_thumb2.cc b/compiler/utils/arm/assembler_thumb2.cc
index cc87856e82..fb3aa1ea85 100644
--- a/compiler/utils/arm/assembler_thumb2.cc
+++ b/compiler/utils/arm/assembler_thumb2.cc
@@ -92,7 +92,7 @@ void Thumb2Assembler::BindLabel(Label* label, uint32_t bound_pc) {
label->BindTo(bound_pc);
}
-void Thumb2Assembler::BindLiterals() {
+uint32_t Thumb2Assembler::BindLiterals() {
// We don't add the padding here, that's done only after adjusting the Fixup sizes.
uint32_t code_size = buffer_.Size();
for (Literal& lit : literals_) {
@@ -100,6 +100,15 @@ void Thumb2Assembler::BindLiterals() {
BindLabel(label, code_size);
code_size += lit.GetSize();
}
+ return code_size;
+}
+
+void Thumb2Assembler::BindJumpTables(uint32_t code_size) {
+ for (JumpTable& table : jump_tables_) {
+ Label* label = table.GetLabel();
+ BindLabel(label, code_size);
+ code_size += table.GetSize();
+ }
}
void Thumb2Assembler::AdjustFixupIfNeeded(Fixup* fixup, uint32_t* current_code_size,
@@ -144,7 +153,7 @@ uint32_t Thumb2Assembler::AdjustFixups() {
AdjustFixupIfNeeded(fixup, &current_code_size, &fixups_to_recalculate);
} while (!fixups_to_recalculate.empty());
- if ((current_code_size & 2) != 0 && !literals_.empty()) {
+ if ((current_code_size & 2) != 0 && (!literals_.empty() || !jump_tables_.empty())) {
// If we need to add padding before literals, this may just push some out of range,
// so recalculate all load literals. This makes up for the fact that we don't mark
// load literal as a dependency of all previous Fixups even though it actually is.
@@ -173,6 +182,13 @@ uint32_t Thumb2Assembler::AdjustFixups() {
label->Reinitialize();
label->BindTo(old_position + literals_adjustment);
}
+ for (JumpTable& table : jump_tables_) {
+ Label* label = table.GetLabel();
+ DCHECK(label->IsBound());
+ int old_position = label->Position();
+ label->Reinitialize();
+ label->BindTo(old_position + literals_adjustment);
+ }
}
return current_code_size;
@@ -229,6 +245,43 @@ void Thumb2Assembler::EmitLiterals() {
}
}
+void Thumb2Assembler::EmitJumpTables() {
+ if (!jump_tables_.empty()) {
+ // Jump tables require 4 byte alignment. (We don't support byte and half-word jump tables.)
+ uint32_t code_size = buffer_.Size();
+ DCHECK_ALIGNED(code_size, 2);
+ if ((code_size & 2u) != 0u) {
+ Emit16(0);
+ }
+ for (JumpTable& table : jump_tables_) {
+ // Bulk ensure capacity, as this may be large.
+ size_t orig_size = buffer_.Size();
+ buffer_.ExtendCapacity(orig_size + table.GetSize());
+#ifndef NDEBUG
+ buffer_.has_ensured_capacity_ = true;
+#endif
+
+ DCHECK_EQ(static_cast<size_t>(table.GetLabel()->Position()), buffer_.Size());
+ int32_t anchor_position = table.GetAnchorLabel()->Position() + 4;
+
+ for (Label* target : table.GetData()) {
+ // Ensure that the label was tracked, so that it will have the right position.
+ DCHECK(std::find(tracked_labels_.begin(), tracked_labels_.end(), target) !=
+ tracked_labels_.end());
+
+ int32_t offset = target->Position() - anchor_position;
+ buffer_.Emit<int32_t>(offset);
+ }
+
+#ifndef NDEBUG
+ buffer_.has_ensured_capacity_ = false;
+#endif
+ size_t new_size = buffer_.Size();
+ DCHECK_LE(new_size - orig_size, table.GetSize());
+ }
+ }
+}
+
inline int16_t Thumb2Assembler::BEncoding16(int32_t offset, Condition cond) {
DCHECK_ALIGNED(offset, 2);
int16_t encoding = B15 | B14;
@@ -382,12 +435,34 @@ inline int32_t Thumb2Assembler::LdrRtRnImm12Encoding(Register rt, Register rn, i
return B31 | B30 | B29 | B28 | B27 | B23 | B22 | B20 | (rn << 16) | (rt << 12) | offset;
}
+inline int16_t Thumb2Assembler::AdrEncoding16(Register rd, int32_t offset) {
+ DCHECK(IsUint<10>(offset));
+ DCHECK(IsAligned<4>(offset));
+ DCHECK(!IsHighRegister(rd));
+ return B15 | B13 | (rd << 8) | (offset >> 2);
+}
+
+inline int32_t Thumb2Assembler::AdrEncoding32(Register rd, int32_t offset) {
+ DCHECK(IsUint<12>(offset));
+ // Bit 26: offset[11]
+ // Bits 14-12: offset[10-8]
+ // Bits 7-0: offset[7-0]
+ int32_t immediate_mask =
+ ((offset & (1 << 11)) << (26 - 11)) |
+ ((offset & (7 << 8)) << (12 - 8)) |
+ (offset & 0xFF);
+ return B31 | B30 | B29 | B28 | B25 | B19 | B18 | B17 | B16 | (rd << 8) | immediate_mask;
+}
+
void Thumb2Assembler::FinalizeCode() {
ArmAssembler::FinalizeCode();
- BindLiterals();
+ uint32_t size_after_literals = BindLiterals();
+ BindJumpTables(size_after_literals);
uint32_t adjusted_code_size = AdjustFixups();
EmitFixups(adjusted_code_size);
EmitLiterals();
+ FinalizeTrackedLabels();
+ EmitJumpTables();
}
bool Thumb2Assembler::ShifterOperandCanAlwaysHold(uint32_t immediate) {
@@ -1770,6 +1845,15 @@ inline size_t Thumb2Assembler::Fixup::SizeInBytes(Size size) {
case kLiteralFar:
return 14u;
+ case kLiteralAddr1KiB:
+ return 2u;
+ case kLiteralAddr4KiB:
+ return 4u;
+ case kLiteralAddr64KiB:
+ return 6u;
+ case kLiteralAddrFar:
+ return 10u;
+
case kLongOrFPLiteral1KiB:
return 4u;
case kLongOrFPLiteral256KiB:
@@ -1831,6 +1915,8 @@ inline int32_t Thumb2Assembler::Fixup::GetOffset(uint32_t current_code_size) con
case kLiteral1KiB:
case kLiteral4KiB:
case kLongOrFPLiteral1KiB:
+ case kLiteralAddr1KiB:
+ case kLiteralAddr4KiB:
DCHECK(diff >= 0 || (GetSize() == kLiteral1KiB && diff == -2));
diff += LiteralPoolPaddingSize(current_code_size);
// Load literal instructions round down the PC+4 to a multiple of 4, so if the PC
@@ -1843,12 +1929,14 @@ inline int32_t Thumb2Assembler::Fixup::GetOffset(uint32_t current_code_size) con
case kLiteral1MiB:
case kLiteral64KiB:
case kLongOrFPLiteral256KiB:
+ case kLiteralAddr64KiB:
DCHECK_GE(diff, 4); // The target must be at least 4 bytes after the ADD rX, PC.
diff -= 4; // One extra 32-bit MOV.
diff += LiteralPoolPaddingSize(current_code_size);
break;
case kLiteralFar:
case kLongOrFPLiteralFar:
+ case kLiteralAddrFar:
DCHECK_GE(diff, 8); // The target must be at least 4 bytes after the ADD rX, PC.
diff -= 8; // Extra MOVW+MOVT; both 32-bit.
diff += LiteralPoolPaddingSize(current_code_size);
@@ -1929,6 +2017,29 @@ uint32_t Thumb2Assembler::Fixup::AdjustSizeIfNeeded(uint32_t current_code_size)
// This encoding can reach any target.
break;
+ case kLiteralAddr1KiB:
+ DCHECK(!IsHighRegister(rn_));
+ if (IsUint<10>(GetOffset(current_code_size))) {
+ break;
+ }
+ current_code_size += IncreaseSize(kLiteralAddr4KiB);
+ FALLTHROUGH_INTENDED;
+ case kLiteralAddr4KiB:
+ if (IsUint<12>(GetOffset(current_code_size))) {
+ break;
+ }
+ current_code_size += IncreaseSize(kLiteralAddr64KiB);
+ FALLTHROUGH_INTENDED;
+ case kLiteralAddr64KiB:
+ if (IsUint<16>(GetOffset(current_code_size))) {
+ break;
+ }
+ current_code_size += IncreaseSize(kLiteralAddrFar);
+ FALLTHROUGH_INTENDED;
+ case kLiteralAddrFar:
+ // This encoding can reach any target.
+ break;
+
case kLongOrFPLiteral1KiB:
if (IsUint<10>(GetOffset(current_code_size))) {
break;
@@ -2055,6 +2166,42 @@ void Thumb2Assembler::Fixup::Emit(AssemblerBuffer* buffer, uint32_t code_size) c
break;
}
+ case kLiteralAddr1KiB: {
+ DCHECK(type_ == kLoadLiteralAddr);
+ int16_t encoding = AdrEncoding16(rn_, GetOffset(code_size));
+ buffer->Store<int16_t>(location_, encoding);
+ break;
+ }
+ case kLiteralAddr4KiB: {
+ DCHECK(type_ == kLoadLiteralAddr);
+ int32_t encoding = AdrEncoding32(rn_, GetOffset(code_size));
+ buffer->Store<int16_t>(location_, encoding >> 16);
+ buffer->Store<int16_t>(location_ + 2u, static_cast<int16_t>(encoding & 0xffff));
+ break;
+ }
+ case kLiteralAddr64KiB: {
+ DCHECK(type_ == kLoadLiteralAddr);
+ int32_t mov_encoding = MovwEncoding32(rn_, GetOffset(code_size));
+ int16_t add_pc_encoding = AddRdnRmEncoding16(rn_, PC);
+ buffer->Store<int16_t>(location_, mov_encoding >> 16);
+ buffer->Store<int16_t>(location_ + 2u, static_cast<int16_t>(mov_encoding & 0xffff));
+ buffer->Store<int16_t>(location_ + 4u, add_pc_encoding);
+ break;
+ }
+ case kLiteralAddrFar: {
+ DCHECK(type_ == kLoadLiteralAddr);
+ int32_t offset = GetOffset(code_size);
+ int32_t movw_encoding = MovwEncoding32(rn_, offset & 0xffff);
+ int32_t movt_encoding = MovtEncoding32(rn_, offset & ~0xffff);
+ int16_t add_pc_encoding = AddRdnRmEncoding16(rn_, PC);
+ buffer->Store<int16_t>(location_, movw_encoding >> 16);
+ buffer->Store<int16_t>(location_ + 2u, static_cast<int16_t>(movw_encoding & 0xffff));
+ buffer->Store<int16_t>(location_ + 4u, movt_encoding >> 16);
+ buffer->Store<int16_t>(location_ + 6u, static_cast<int16_t>(movt_encoding & 0xffff));
+ buffer->Store<int16_t>(location_ + 8u, add_pc_encoding);
+ break;
+ }
+
case kLongOrFPLiteral1KiB: {
int32_t encoding = LoadWideOrFpEncoding(PC, GetOffset(code_size)); // DCHECKs type_.
buffer->Store<int16_t>(location_, encoding >> 16);
@@ -3260,6 +3407,25 @@ void Thumb2Assembler::AddConstant(Register rd, Register rn, int32_t value,
}
}
+void Thumb2Assembler::CmpConstant(Register rn, int32_t value, Condition cond) {
+ // We prefer to select the shorter code sequence rather than selecting add for
+ // positive values and sub for negatives ones, which would slightly improve
+ // the readability of generated code for some constants.
+ ShifterOperand shifter_op;
+ if (ShifterOperandCanHold(kNoRegister, rn, CMP, value, &shifter_op)) {
+ cmp(rn, shifter_op, cond);
+ } else if (ShifterOperandCanHold(kNoRegister, rn, CMN, ~value, &shifter_op)) {
+ cmn(rn, shifter_op, cond);
+ } else {
+ CHECK(rn != IP);
+ movw(IP, Low16Bits(value), cond);
+ uint16_t value_high = High16Bits(value);
+ if (value_high != 0) {
+ movt(IP, value_high, cond);
+ }
+ cmp(rn, ShifterOperand(IP), cond);
+ }
+}
void Thumb2Assembler::LoadImmediate(Register rd, int32_t value, Condition cond) {
ShifterOperand shifter_op;
@@ -3476,5 +3642,39 @@ void Thumb2Assembler::CompareAndBranchIfNonZero(Register r, Label* label) {
b(label, NE);
}
}
+
+JumpTable* Thumb2Assembler::CreateJumpTable(std::vector<Label*>&& labels, Register base_reg) {
+ jump_tables_.emplace_back(std::move(labels));
+ JumpTable* table = &jump_tables_.back();
+ DCHECK(!table->GetLabel()->IsBound());
+
+ bool use32bit = IsForced32Bit() || IsHighRegister(base_reg);
+ uint32_t location = buffer_.Size();
+ Fixup::Size size = use32bit ? Fixup::kLiteralAddr4KiB : Fixup::kLiteralAddr1KiB;
+ FixupId fixup_id = AddFixup(Fixup::LoadLiteralAddress(location, base_reg, size));
+ Emit16(static_cast<uint16_t>(table->GetLabel()->position_));
+ table->GetLabel()->LinkTo(fixup_id);
+ if (use32bit) {
+ Emit16(0);
+ }
+ DCHECK_EQ(location + GetFixup(fixup_id)->GetSizeInBytes(), buffer_.Size());
+
+ return table;
+}
+
+void Thumb2Assembler::EmitJumpTableDispatch(JumpTable* jump_table, Register displacement_reg) {
+ CHECK(!IsForced32Bit()) << "Forced 32-bit dispatch not implemented yet";
+ // 32-bit ADD doesn't support PC as an input, so we need a two-instruction sequence:
+ // SUB ip, ip, #0
+ // ADD pc, ip, reg
+ // TODO: Implement.
+
+ // The anchor's position needs to be fixed up before we can compute offsets - so make it a tracked
+ // label.
+ BindTrackedLabel(jump_table->GetAnchorLabel());
+
+ add(PC, PC, ShifterOperand(displacement_reg));
+}
+
} // namespace arm
} // namespace art
generated by cgit v1.2.3-59-g8ed1b (git 2.39.0) at 2025-12-10 15:40:15 +0000