[optimizing] Add basic PackedSwitch support
Add HPackedSwitch, and generate it from the builder. Code generators
convert this to a series of compare/branch tests. Better implementation
in the code generators as a real jump table will follow as separate CLs.
Change-Id: If14736fa4d62809b6ae95280148c55682e856911
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 32a1db5..7ee974f 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -5180,6 +5180,38 @@
// Will be generated at use site.
}
+// Simple implementation of packed switch - generate cascaded compare/jumps.
+void LocationsBuilderX86_64::VisitPackedSwitch(HPackedSwitch* switch_instr) {
+ LocationSummary* locations =
+ new (GetGraph()->GetArena()) LocationSummary(switch_instr, LocationSummary::kNoCall);
+ locations->SetInAt(0, 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>();
+ HBasicBlock* default_block = switch_instr->GetDefaultBlock();
+
+ // 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.at(i)));
+ }
+
+ // And the default for any other value.
+ if (!codegen_->GoesToNextBlock(switch_instr->GetBlock(), default_block)) {
+ __ jmp(codegen_->GetLabelOf(default_block));
+ }
+}
+
void CodeGeneratorX86_64::Load64BitValue(CpuRegister dest, int64_t value) {
if (value == 0) {
__ xorl(dest, dest);