[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_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index 580e93e..40dfedd 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -3533,6 +3533,38 @@
// Will be generated at use site.
}
+// Simple implementation of packed switch - generate cascaded compare/jumps.
+void LocationsBuilderARM64::VisitPackedSwitch(HPackedSwitch* switch_instr) {
+ LocationSummary* locations =
+ new (GetGraph()->GetArena()) LocationSummary(switch_instr, LocationSummary::kNoCall);
+ locations->SetInAt(0, Location::RequiresRegister());
+}
+
+void InstructionCodeGeneratorARM64::VisitPackedSwitch(HPackedSwitch* switch_instr) {
+ int32_t lower_bound = switch_instr->GetStartValue();
+ int32_t num_entries = switch_instr->GetNumEntries();
+ Register value_reg = InputRegisterAt(switch_instr, 0);
+ HBasicBlock* default_block = switch_instr->GetDefaultBlock();
+
+ // Create a series of compare/jumps.
+ const ArenaVector<HBasicBlock*>& successors = switch_instr->GetBlock()->GetSuccessors();
+ for (int32_t i = 0; i < num_entries; i++) {
+ int32_t case_value = lower_bound + i;
+ vixl::Label* succ = codegen_->GetLabelOf(successors.at(i));
+ if (case_value == 0) {
+ __ Cbz(value_reg, succ);
+ } else {
+ __ Cmp(value_reg, vixl::Operand(case_value));
+ __ B(eq, succ);
+ }
+ }
+
+ // And the default for any other value.
+ if (!codegen_->GoesToNextBlock(switch_instr->GetBlock(), default_block)) {
+ __ B(codegen_->GetLabelOf(default_block));
+ }
+}
+
#undef __
#undef QUICK_ENTRY_POINT