riscv64: Support auto-compression for ebreak/unimp

Emit automatically corresponding compressed instruction

Add tests

Test: m test-art-host-gtest
Test: run-gtests.sh
Test: testrunner.py --target --optimizing
Bug: 328561342
Change-Id: Iea334f94f0f0b30d05442df10b5bd0efae19857a

2 files changed, 25 insertions, 5 deletions

diff --git a/compiler/utils/riscv64/assembler_riscv64.cc b/compiler/utils/riscv64/assembler_riscv64.cc
index 82536999b4..db9aac6793 100644
--- a/compiler/utils/riscv64/assembler_riscv64.cc
+++ b/compiler/utils/riscv64/assembler_riscv64.cc
@@ -559,7 +559,14 @@ void Riscv64Assembler::Sraw(XRegister rd, XRegister rs1, XRegister rs2) {
 
 void Riscv64Assembler::Ecall() { EmitI(0x0, 0x0, 0x0, 0x0, 0x73); }
 
-void Riscv64Assembler::Ebreak() { EmitI(0x1, 0x0, 0x0, 0x0, 0x73); }
+void Riscv64Assembler::Ebreak() {
+  if (IsExtensionEnabled(Riscv64Extension::kZca)) {
+    CEbreak();
+    return;
+  }
+
+  EmitI(0x1, 0x0, 0x0, 0x0, 0x73);
+}
 
 // Fence instruction (RV32I): opcode = 0xf, funct3 = 0
 
@@ -6489,8 +6496,11 @@ void Riscv64Assembler::FLoadd(FRegister rd, Literal* literal) {
 }
 
 void Riscv64Assembler::Unimp() {
-  // TODO(riscv64): use 16-bit zero C.UNIMP once we support compression
-  Emit32(0xC0001073);
+  if (IsExtensionEnabled(Riscv64Extension::kZca)) {
+    CUnimp();
+  } else {
+    Emit32(0xC0001073);
+  }
 }
 
 /////////////////////////////// RV64 MACRO Instructions END ///////////////////////////////
diff --git a/compiler/utils/riscv64/assembler_riscv64_test.cc b/compiler/utils/riscv64/assembler_riscv64_test.cc
index 95bc6560b9..120dfc4f35 100644
--- a/compiler/utils/riscv64/assembler_riscv64_test.cc
+++ b/compiler/utils/riscv64/assembler_riscv64_test.cc
@@ -2616,11 +2616,16 @@ TEST_F(AssemblerRISCV64Test, Ecall) {
 }
 
 TEST_F(AssemblerRISCV64Test, Ebreak) {
-  ScopedCSuppression scs(this);
   __ Ebreak();
   DriverStr("ebreak\n", "Ebreak");
 }
 
+TEST_F(AssemblerRISCV64Test, Ebreak_WithoutC) {
+  ScopedCSuppression scs(this);
+  __ Ebreak();
+  DriverStr("ebreak\n", "Ebreak_WithoutC");
+}
+
 TEST_F(AssemblerRISCV64Test, Fence) {
   auto get_fence_type_string = [](uint32_t fence_type) {
     CHECK_LE(fence_type, 0xfu);
@@ -8789,11 +8794,16 @@ TEST_F(AssemblerRISCV64Test, FStored) {
 }
 
 TEST_F(AssemblerRISCV64Test, Unimp) {
-  ScopedCSuppression scs(this);
   __ Unimp();
   DriverStr("unimp\n", "Unimp");
 }
 
+TEST_F(AssemblerRISCV64Test, Unimp_WithoutC) {
+  ScopedCSuppression scs(this);
+  __ Unimp();
+  DriverStr("unimp\n", "Unimp_WithoutC");
+}
+
 TEST_F(AssemblerRISCV64Test, LoadLabelAddress) {
   std::string expected;
   constexpr size_t kNumLoadsForward = 4 * KB;