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Merge pull request #11959 from Dentomologist/add_x64emitter_unittests

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x64EmitterTest: add J/J_CC/CALL unit tests
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JosJuice 2023-08-21 16:27:04 +02:00 committed by GitHub
commit 3451cb1ca2
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1 changed files with 103 additions and 12 deletions
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115
Source/UnitTests/Common/x64EmitterTest.cpp
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@ -128,6 +128,9 @@ protected:
} }
void TearDown() override { cpu_info = CPUInfo(); } void TearDown() override { cpu_info = CPUInfo(); }
void ResetCodeBuffer() { emitter->SetCodePtr(code_buffer, code_buffer_end); }
void ExpectDisassembly(const std::string& expected) void ExpectDisassembly(const std::string& expected)
{ {
std::string disasmed; std::string disasmed;
@ -186,8 +189,16 @@ protected:
EXPECT_EQ(expected_norm, disasmed_norm); EXPECT_EQ(expected_norm, disasmed_norm);
// Reset code buffer afterwards. ResetCodeBuffer();
emitter->SetCodePtr(code_buffer, code_buffer_end); }
void ExpectBytes(const std::vector<u8> expected_bytes)
{
const std::vector<u8> code_bytes(code_buffer, emitter->GetWritableCodePtr());
EXPECT_EQ(expected_bytes, code_bytes);
ResetCodeBuffer();
} }
std::unique_ptr<X64CodeBlock> emitter; std::unique_ptr<X64CodeBlock> emitter;
@ -286,15 +297,13 @@ TEST_F(x64EmitterTest, POP_Register)
TEST_F(x64EmitterTest, JMP) TEST_F(x64EmitterTest, JMP)
{ {
emitter->NOP(6); emitter->NOP(1);
emitter->JMP(code_buffer); emitter->JMP(code_buffer, XEmitter::Jump::Short);
ExpectDisassembly("multibyte nop " ExpectBytes({/* nop */ 0x90, /* short jmp */ 0xeb, /* offset -3 */ 0xfd});
"jmp .-8");
emitter->NOP(6); emitter->NOP(1);
emitter->JMP(code_buffer, XEmitter::Jump::Near); emitter->JMP(code_buffer, XEmitter::Jump::Near);
ExpectDisassembly("multibyte nop " ExpectBytes({/* nop */ 0x90, /* near jmp */ 0xe9, /* offset -6 */ 0xfa, 0xff, 0xff, 0xff});
"jmp .-11");
} }
TEST_F(x64EmitterTest, JMPptr_Register) TEST_F(x64EmitterTest, JMPptr_Register)
@ -306,11 +315,93 @@ TEST_F(x64EmitterTest, JMPptr_Register)
} }
} }
// TODO: J/SetJumpTarget TEST_F(x64EmitterTest, J)
{
FixupBranch jump = emitter->J(XEmitter::Jump::Short);
emitter->NOP(1);
emitter->SetJumpTarget(jump);
ExpectBytes({/* short jmp */ 0xeb, /* offset 1 */ 0x1, /* nop */ 0x90});
// TODO: CALL jump = emitter->J(XEmitter::Jump::Near);
emitter->NOP(1);
emitter->SetJumpTarget(jump);
ExpectBytes({/* near jmp */ 0xe9, /* offset 1 */ 0x1, 0x0, 0x0, 0x0, /* nop */ 0x90});
}
// TODO: J_CC TEST_F(x64EmitterTest, CALL)
{
FixupBranch call = emitter->CALL();
emitter->NOP(6);
emitter->SetJumpTarget(call);
ExpectDisassembly("call .+6 "
"multibyte nop");
const u8* const code_start = emitter->GetCodePtr();
emitter->CALL(code_start + 5);
ExpectDisassembly("call .+0");
emitter->NOP(6);
emitter->CALL(code_start);
ExpectDisassembly("multibyte nop "
"call .-11");
}
TEST_F(x64EmitterTest, J_CC)
{
for (const auto& [condition_code, condition_name] : ccnames)
{
FixupBranch fixup = emitter->J_CC(condition_code, XEmitter::Jump::Short);
emitter->NOP(1);
emitter->SetJumpTarget(fixup);
const u8 short_jump_condition_opcode = 0x70 + condition_code;
ExpectBytes({short_jump_condition_opcode, /* offset 1 */ 0x1, /* nop */ 0x90});
fixup = emitter->J_CC(condition_code, XEmitter::Jump::Near);
emitter->NOP(1);
emitter->SetJumpTarget(fixup);
const u8 near_jump_condition_opcode = 0x80 + condition_code;
ExpectBytes({/* two byte opcode */ 0x0f, near_jump_condition_opcode, /* offset 1 */ 0x1, 0x0,
0x0, 0x0, /* nop */ 0x90});
}
// Verify a short jump is used when possible and a near jump when needed.
//
// A short jump to a particular address and a near jump to that same address will have different
// offsets. This is because short jumps are 2 bytes and near jumps are 6 bytes, and the offset to
// the target is calculated from the address of the next instruction.
const u8* const code_start = emitter->GetCodePtr();
constexpr int short_jump_bytes = 2;
const u8* const next_byte_after_short_jump_instruction = code_start + short_jump_bytes;
constexpr int longest_backward_short_jump = 0x80;
const u8* const furthest_byte_reachable_with_backward_short_jump =
next_byte_after_short_jump_instruction - longest_backward_short_jump;
emitter->J_CC(CC_O, furthest_byte_reachable_with_backward_short_jump);
ExpectBytes({/* JO opcode */ 0x70, /* offset -128 */ 0x80});
const u8* const closest_byte_requiring_backward_near_jump =
furthest_byte_reachable_with_backward_short_jump - 1;
emitter->J_CC(CC_O, closest_byte_requiring_backward_near_jump);
// This offset is 5 less than the offset for the furthest backward short jump. -1 because this
// target is 1 byte before the short target, and -4 because the address of the next instruction is
// 4 bytes further away from the jump target than it would be with a short jump.
ExpectBytes({/* two byte JO opcode */ 0x0f, 0x80, /* offset -133 */ 0x7b, 0xff, 0xff, 0xff});
constexpr int longest_forward_short_jump = 0x7f;
const u8* const furthest_byte_reachable_with_forward_short_jump =
next_byte_after_short_jump_instruction + longest_forward_short_jump;
emitter->J_CC(CC_O, furthest_byte_reachable_with_forward_short_jump);
ExpectBytes({/* JO opcode */ 0x70, /* offset 127 */ 0x7f});
const u8* const closest_byte_requiring_forward_near_jump =
furthest_byte_reachable_with_forward_short_jump + 1;
emitter->J_CC(CC_O, closest_byte_requiring_forward_near_jump);
// This offset is 3 less than the offset for the furthest forward short jump. +1 because this
// target is 1 byte after the short target, and -4 because the address of the next instruction is
// 4 bytes closer to the jump target than it would be with a short jump.
ExpectBytes({/* two byte JO opcode */ 0x0f, 0x80, /* offset 124 */ 0x7c, 0x0, 0x0, 0x0});
}
TEST_F(x64EmitterTest, SETcc) TEST_F(x64EmitterTest, SETcc)
{ {