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LibJIT: Support jumps to already linked labels

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This commit is contained in:
Simon Wanner 2023-10-28 20:12:40 +02:00 • committed by Andreas Kling
parent b2d8d0c270
commit ff265d1900
1 changed files with 26 additions and 21 deletions
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37
Userland/Libraries/LibJIT/Assembler.h
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@ -219,12 +219,14 @@ struct Assembler {
}
struct Label {
size_t offset_of_label_in_instruction_stream { 0 };
Optional<size_t> offset_of_label_in_instruction_stream;
Vector<size_t> jump_slot_offsets_in_instruction_stream;
void add_jump(size_t offset)
void add_jump(Assembler& assembler, size_t offset)
{
jump_slot_offsets_in_instruction_stream.append(offset);
if (offset_of_label_in_instruction_stream.has_value())
link_jump(assembler, offset);
}
void link(Assembler& assembler)
@ -234,24 +236,27 @@ struct Assembler {
void link_to(Assembler& assembler, size_t link_offset)
{
VERIFY(!offset_of_label_in_instruction_stream.has_value());
offset_of_label_in_instruction_stream = link_offset;
for (auto offset_in_instruction_stream : jump_slot_offsets_in_instruction_stream) {
auto offset = offset_of_label_in_instruction_stream - offset_in_instruction_stream;
for (auto offset_in_instruction_stream : jump_slot_offsets_in_instruction_stream)
link_jump(assembler, offset_in_instruction_stream);
}
private:
void link_jump(Assembler& assembler, size_t offset_in_instruction_stream)
{
auto offset = offset_of_label_in_instruction_stream.value() - offset_in_instruction_stream;
auto jump_slot = offset_in_instruction_stream - 4;
assembler.m_output[jump_slot + 0] = (offset >> 0) & 0xff;
assembler.m_output[jump_slot + 1] = (offset >> 8) & 0xff;
assembler.m_output[jump_slot + 2] = (offset >> 16) & 0xff;
assembler.m_output[jump_slot + 3] = (offset >> 24) & 0xff;
}
}
};
[[nodiscard]] Label make_label()
{
return Label {
.offset_of_label_in_instruction_stream = m_output.size(),
.jump_slot_offsets_in_instruction_stream = {},
};
return Label {};
}
[[nodiscard]] Label jump()
@ -260,7 +265,7 @@ struct Assembler {
emit8(0xe9);
emit32(0xdeadbeef);
auto label = make_label();
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
return label;
}
@ -269,7 +274,7 @@ struct Assembler {
// jmp target (RIP-relative 32-bit offset)
emit8(0xe9);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void jump(Operand op)
@ -341,7 +346,7 @@ struct Assembler {
emit8(0x0f);
emit8(0x84);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void jump_if_not_zero(Operand reg, Label& label)
@ -352,7 +357,7 @@ struct Assembler {
emit8(0x0f);
emit8(0x85);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void jump_if_equal(Operand lhs, Operand rhs, Label& label)
@ -368,7 +373,7 @@ struct Assembler {
emit8(0x0f);
emit8(0x84);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void jump_if_not_equal(Operand lhs, Operand rhs, Label& label)
@ -384,7 +389,7 @@ struct Assembler {
emit8(0x0f);
emit8(0x85);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void jump_if_less_than(Operand lhs, Operand rhs, Label& label)
@ -395,7 +400,7 @@ struct Assembler {
emit8(0x0f);
emit8(0x8c);
emit32(0xdeadbeef);
label.add_jump(m_output.size());
label.add_jump(*this, m_output.size());
}
void sign_extend_32_to_64_bits(Reg reg)