x86/x86-64: Avoid temporary for read barrier field load.

Add TEST instructions for memory and immediate. Use the byte
version to avoid a temporary in read barrier field load.

Test: Tested with ART_USE_READ_BARRIER=true on host.
Test: Tested with ART_USE_READ_BARRIER=true ART_HEAP_POISONING=true on host.
Bug: 29966877
Bug: 12687968
Change-Id: Ia415d3c2e1ae1ff6dff11d72bbb7d96d5deed6ee

1 files changed, 17 insertions, 0 deletions

diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index f1a991574b..f2ef41f400 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1148,6 +1148,23 @@ void X86Assembler::testl(Register reg, const Immediate& immediate) {
 }
 
 
+void X86Assembler::testb(const Address& dst, const Immediate& imm) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF6);
+  EmitOperand(EAX, dst);
+  CHECK(imm.is_int8());
+  EmitUint8(imm.value() & 0xFF);
+}
+
+
+void X86Assembler::testl(const Address& dst, const Immediate& imm) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF7);
+  EmitOperand(0, dst);
+  EmitImmediate(imm);
+}
+
+
 void X86Assembler::andl(Register dst, Register src) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x23);