X86_64 jump tables for PackedSwitch
Implement PackedSwitch using a jump table of offsets to blocks.
Bug: 24092914
Bug: 21119474
Change-Id: I83430086c03ef728d30d79b4022607e9245ef98f
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 21120a0..f0d9420 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -670,7 +670,8 @@
constant_area_start_(0),
method_patches_(graph->GetArena()->Adapter(kArenaAllocCodeGenerator)),
relative_call_patches_(graph->GetArena()->Adapter(kArenaAllocCodeGenerator)),
- pc_rel_dex_cache_patches_(graph->GetArena()->Adapter(kArenaAllocCodeGenerator)) {
+ pc_rel_dex_cache_patches_(graph->GetArena()->Adapter(kArenaAllocCodeGenerator)),
+ fixups_to_jump_tables_(graph->GetArena()->Adapter(kArenaAllocCodeGenerator)) {
AddAllocatedRegister(Location::RegisterLocation(kFakeReturnRegister));
}
@@ -5322,31 +5323,43 @@
LocationSummary* locations =
new (GetGraph()->GetArena()) LocationSummary(switch_instr, LocationSummary::kNoCall);
locations->SetInAt(0, Location::RequiresRegister());
+ locations->AddTemp(Location::RequiresRegister());
+ locations->AddTemp(Location::RequiresRegister());
}
void InstructionCodeGeneratorX86_64::VisitPackedSwitch(HPackedSwitch* switch_instr) {
int32_t lower_bound = switch_instr->GetStartValue();
int32_t num_entries = switch_instr->GetNumEntries();
LocationSummary* locations = switch_instr->GetLocations();
- CpuRegister value_reg = locations->InAt(0).AsRegister<CpuRegister>();
+ CpuRegister value_reg_in = locations->InAt(0).AsRegister<CpuRegister>();
+ CpuRegister temp_reg = locations->GetTemp(0).AsRegister<CpuRegister>();
+ CpuRegister base_reg = locations->GetTemp(1).AsRegister<CpuRegister>();
+
+ // Remove the bias, if needed.
+ Register value_reg_out = value_reg_in.AsRegister();
+ if (lower_bound != 0) {
+ __ leal(temp_reg, Address(value_reg_in, -lower_bound));
+ value_reg_out = temp_reg.AsRegister();
+ }
+ CpuRegister value_reg(value_reg_out);
+
+ // Is the value in range?
HBasicBlock* default_block = switch_instr->GetDefaultBlock();
+ __ cmpl(value_reg, Immediate(num_entries - 1));
+ __ j(kAbove, codegen_->GetLabelOf(default_block));
- // Create a series of compare/jumps.
- const ArenaVector<HBasicBlock*>& successors = switch_instr->GetBlock()->GetSuccessors();
- for (int i = 0; i < num_entries; i++) {
- int32_t case_value = lower_bound + i;
- if (case_value == 0) {
- __ testl(value_reg, value_reg);
- } else {
- __ cmpl(value_reg, Immediate(case_value));
- }
- __ j(kEqual, codegen_->GetLabelOf(successors[i]));
- }
+ // We are in the range of the table.
+ // Load the address of the jump table in the constant area.
+ __ leaq(base_reg, codegen_->LiteralCaseTable(switch_instr));
- // And the default for any other value.
- if (!codegen_->GoesToNextBlock(switch_instr->GetBlock(), default_block)) {
- __ jmp(codegen_->GetLabelOf(default_block));
- }
+ // Load the (signed) offset from the jump table.
+ __ movsxd(temp_reg, Address(base_reg, value_reg, TIMES_4, 0));
+
+ // Add the offset to the address of the table base.
+ __ addq(temp_reg, base_reg);
+
+ // And jump.
+ __ jmp(temp_reg);
}
void CodeGeneratorX86_64::Load64BitValue(CpuRegister dest, int64_t value) {
@@ -5372,15 +5385,85 @@
}
}
+/**
+ * Class to handle late fixup of offsets into constant area.
+ */
+class RIPFixup : public AssemblerFixup, public ArenaObject<kArenaAllocCodeGenerator> {
+ public:
+ RIPFixup(CodeGeneratorX86_64& codegen, size_t offset)
+ : codegen_(&codegen), offset_into_constant_area_(offset) {}
+
+ protected:
+ void SetOffset(size_t offset) { offset_into_constant_area_ = offset; }
+
+ CodeGeneratorX86_64* codegen_;
+
+ private:
+ void Process(const MemoryRegion& region, int pos) OVERRIDE {
+ // Patch the correct offset for the instruction. We use the address of the
+ // 'next' instruction, which is 'pos' (patch the 4 bytes before).
+ int32_t constant_offset = codegen_->ConstantAreaStart() + offset_into_constant_area_;
+ int32_t relative_position = constant_offset - pos;
+
+ // Patch in the right value.
+ region.StoreUnaligned<int32_t>(pos - 4, relative_position);
+ }
+
+ // Location in constant area that the fixup refers to.
+ size_t offset_into_constant_area_;
+};
+
+/**
+ t * Class to handle late fixup of offsets to a jump table that will be created in the
+ * constant area.
+ */
+class JumpTableRIPFixup : public RIPFixup {
+ public:
+ JumpTableRIPFixup(CodeGeneratorX86_64& codegen, HPackedSwitch* switch_instr)
+ : RIPFixup(codegen, -1), switch_instr_(switch_instr) {}
+
+ void CreateJumpTable() {
+ X86_64Assembler* assembler = codegen_->GetAssembler();
+
+ // Ensure that the reference to the jump table has the correct offset.
+ const int32_t offset_in_constant_table = assembler->ConstantAreaSize();
+ SetOffset(offset_in_constant_table);
+
+ // Compute the offset from the start of the function to this jump table.
+ const int32_t current_table_offset = assembler->CodeSize() + offset_in_constant_table;
+
+ // Populate the jump table with the correct values for the jump table.
+ int32_t num_entries = switch_instr_->GetNumEntries();
+ HBasicBlock* block = switch_instr_->GetBlock();
+ const ArenaVector<HBasicBlock*>& successors = block->GetSuccessors();
+ // The value that we want is the target offset - the position of the table.
+ for (int32_t i = 0; i < num_entries; i++) {
+ HBasicBlock* b = successors[i];
+ Label* l = codegen_->GetLabelOf(b);
+ DCHECK(l->IsBound());
+ int32_t offset_to_block = l->Position() - current_table_offset;
+ assembler->AppendInt32(offset_to_block);
+ }
+ }
+
+ private:
+ const HPackedSwitch* switch_instr_;
+};
+
void CodeGeneratorX86_64::Finalize(CodeAllocator* allocator) {
// Generate the constant area if needed.
X86_64Assembler* assembler = GetAssembler();
- if (!assembler->IsConstantAreaEmpty()) {
- // Align to 4 byte boundary to reduce cache misses, as the data is 4 and 8
- // byte values. If used for vectors at a later time, this will need to be
- // updated to 16 bytes with the appropriate offset.
+ if (!assembler->IsConstantAreaEmpty() || !fixups_to_jump_tables_.empty()) {
+ // Align to 4 byte boundary to reduce cache misses, as the data is 4 and 8 byte values.
assembler->Align(4, 0);
constant_area_start_ = assembler->CodeSize();
+
+ // Populate any jump tables.
+ for (auto jump_table : fixups_to_jump_tables_) {
+ jump_table->CreateJumpTable();
+ }
+
+ // And now add the constant area to the generated code.
assembler->AddConstantArea();
}
@@ -5388,31 +5471,6 @@
CodeGenerator::Finalize(allocator);
}
-/**
- * Class to handle late fixup of offsets into constant area.
- */
-class RIPFixup : public AssemblerFixup, public ArenaObject<kArenaAllocCodeGenerator> {
- public:
- RIPFixup(const CodeGeneratorX86_64& codegen, int offset)
- : codegen_(codegen), offset_into_constant_area_(offset) {}
-
- private:
- void Process(const MemoryRegion& region, int pos) OVERRIDE {
- // Patch the correct offset for the instruction. We use the address of the
- // 'next' instruction, which is 'pos' (patch the 4 bytes before).
- int constant_offset = codegen_.ConstantAreaStart() + offset_into_constant_area_;
- int relative_position = constant_offset - pos;
-
- // Patch in the right value.
- region.StoreUnaligned<int32_t>(pos - 4, relative_position);
- }
-
- const CodeGeneratorX86_64& codegen_;
-
- // Location in constant area that the fixup refers to.
- int offset_into_constant_area_;
-};
-
Address CodeGeneratorX86_64::LiteralDoubleAddress(double v) {
AssemblerFixup* fixup = new (GetGraph()->GetArena()) RIPFixup(*this, __ AddDouble(v));
return Address::RIP(fixup);
@@ -5453,6 +5511,16 @@
GetMoveResolver()->EmitNativeCode(¶llel_move);
}
+Address CodeGeneratorX86_64::LiteralCaseTable(HPackedSwitch* switch_instr) {
+ // Create a fixup to be used to create and address the jump table.
+ JumpTableRIPFixup* table_fixup =
+ new (GetGraph()->GetArena()) JumpTableRIPFixup(*this, switch_instr);
+
+ // We have to populate the jump tables.
+ fixups_to_jump_tables_.push_back(table_fixup);
+ return Address::RIP(table_fixup);
+}
+
#undef __
} // namespace x86_64
diff --git a/compiler/optimizing/code_generator_x86_64.h b/compiler/optimizing/code_generator_x86_64.h
index d6a6a7e..dc86a48 100644
--- a/compiler/optimizing/code_generator_x86_64.h
+++ b/compiler/optimizing/code_generator_x86_64.h
@@ -234,6 +234,9 @@
DISALLOW_COPY_AND_ASSIGN(InstructionCodeGeneratorX86_64);
};
+// Class for fixups to jump tables.
+class JumpTableRIPFixup;
+
class CodeGeneratorX86_64 : public CodeGenerator {
public:
CodeGeneratorX86_64(HGraph* graph,
@@ -354,6 +357,7 @@
// Load a 64 bit value into a register in the most efficient manner.
void Load64BitValue(CpuRegister dest, int64_t value);
+ Address LiteralCaseTable(HPackedSwitch* switch_instr);
// Store a 64 bit value into a DoubleStackSlot in the most efficient manner.
void Store64BitValueToStack(Location dest, int64_t value);
@@ -391,6 +395,9 @@
// We will fix this up in the linker later to have the right value.
static constexpr int32_t kDummy32BitOffset = 256;
+ // Fixups for jump tables need to be handled specially.
+ ArenaVector<JumpTableRIPFixup*> fixups_to_jump_tables_;
+
DISALLOW_COPY_AND_ASSIGN(CodeGeneratorX86_64);
};
diff --git a/compiler/utils/x86_64/assembler_x86_64.cc b/compiler/utils/x86_64/assembler_x86_64.cc
index 6e7d74d..9eb5e67 100644
--- a/compiler/utils/x86_64/assembler_x86_64.cc
+++ b/compiler/utils/x86_64/assembler_x86_64.cc
@@ -3122,7 +3122,14 @@
}
}
-int ConstantArea::AddInt32(int32_t v) {
+size_t ConstantArea::AppendInt32(int32_t v) {
+ size_t result = buffer_.size() * elem_size_;
+ buffer_.push_back(v);
+ return result;
+}
+
+size_t ConstantArea::AddInt32(int32_t v) {
+ // Look for an existing match.
for (size_t i = 0, e = buffer_.size(); i < e; i++) {
if (v == buffer_[i]) {
return i * elem_size_;
@@ -3130,12 +3137,10 @@
}
// Didn't match anything.
- int result = buffer_.size() * elem_size_;
- buffer_.push_back(v);
- return result;
+ return AppendInt32(v);
}
-int ConstantArea::AddInt64(int64_t v) {
+size_t ConstantArea::AddInt64(int64_t v) {
int32_t v_low = v;
int32_t v_high = v >> 32;
if (buffer_.size() > 1) {
@@ -3148,18 +3153,18 @@
}
// Didn't match anything.
- int result = buffer_.size() * elem_size_;
+ size_t result = buffer_.size() * elem_size_;
buffer_.push_back(v_low);
buffer_.push_back(v_high);
return result;
}
-int ConstantArea::AddDouble(double v) {
+size_t ConstantArea::AddDouble(double v) {
// Treat the value as a 64-bit integer value.
return AddInt64(bit_cast<int64_t, double>(v));
}
-int ConstantArea::AddFloat(float v) {
+size_t ConstantArea::AddFloat(float v) {
// Treat the value as a 32-bit integer value.
return AddInt32(bit_cast<int32_t, float>(v));
}
diff --git a/compiler/utils/x86_64/assembler_x86_64.h b/compiler/utils/x86_64/assembler_x86_64.h
index 255f551..01d28e3 100644
--- a/compiler/utils/x86_64/assembler_x86_64.h
+++ b/compiler/utils/x86_64/assembler_x86_64.h
@@ -269,36 +269,40 @@
* Class to handle constant area values.
*/
class ConstantArea {
- public:
- ConstantArea() {}
+ public:
+ ConstantArea() {}
- // Add a double to the constant area, returning the offset into
- // the constant area where the literal resides.
- int AddDouble(double v);
+ // Add a double to the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AddDouble(double v);
- // Add a float to the constant area, returning the offset into
- // the constant area where the literal resides.
- int AddFloat(float v);
+ // Add a float to the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AddFloat(float v);
- // Add an int32_t to the constant area, returning the offset into
- // the constant area where the literal resides.
- int AddInt32(int32_t v);
+ // Add an int32_t to the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AddInt32(int32_t v);
- // Add an int64_t to the constant area, returning the offset into
- // the constant area where the literal resides.
- int AddInt64(int64_t v);
+ // Add an int32_t to the end of the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AppendInt32(int32_t v);
- int GetSize() const {
- return buffer_.size() * elem_size_;
- }
+ // Add an int64_t to the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AddInt64(int64_t v);
- const std::vector<int32_t>& GetBuffer() const {
- return buffer_;
- }
+ size_t GetSize() const {
+ return buffer_.size() * elem_size_;
+ }
- private:
- static constexpr size_t elem_size_ = sizeof(int32_t);
- std::vector<int32_t> buffer_;
+ const std::vector<int32_t>& GetBuffer() const {
+ return buffer_;
+ }
+
+ private:
+ static constexpr size_t elem_size_ = sizeof(int32_t);
+ std::vector<int32_t> buffer_;
};
@@ -806,19 +810,27 @@
// Add a double to the constant area, returning the offset into
// the constant area where the literal resides.
- int AddDouble(double v) { return constant_area_.AddDouble(v); }
+ size_t AddDouble(double v) { return constant_area_.AddDouble(v); }
// Add a float to the constant area, returning the offset into
// the constant area where the literal resides.
- int AddFloat(float v) { return constant_area_.AddFloat(v); }
+ size_t AddFloat(float v) { return constant_area_.AddFloat(v); }
// Add an int32_t to the constant area, returning the offset into
// the constant area where the literal resides.
- int AddInt32(int32_t v) { return constant_area_.AddInt32(v); }
+ size_t AddInt32(int32_t v) {
+ return constant_area_.AddInt32(v);
+ }
+
+ // Add an int32_t to the end of the constant area, returning the offset into
+ // the constant area where the literal resides.
+ size_t AppendInt32(int32_t v) {
+ return constant_area_.AppendInt32(v);
+ }
// Add an int64_t to the constant area, returning the offset into
// the constant area where the literal resides.
- int AddInt64(int64_t v) { return constant_area_.AddInt64(v); }
+ size_t AddInt64(int64_t v) { return constant_area_.AddInt64(v); }
// Add the contents of the constant area to the assembler buffer.
void AddConstantArea();
@@ -826,6 +838,9 @@
// Is the constant area empty? Return true if there are no literals in the constant area.
bool IsConstantAreaEmpty() const { return constant_area_.GetSize() == 0; }
+ // Return the current size of the constant area.
+ size_t ConstantAreaSize() const { return constant_area_.GetSize(); }
+
//
// Heap poisoning.
//
