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[a64] Use VectorCodeGenerator rather than CodeBlock+CodeGenerator
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The emitter doesn't actually hold onto executable code, but just
generates the assembly-data into a buffer for the currently-resolving
function before placing it into a code-cache. When code gets pushed into
the code-cache, it can just be copied from an `std::vector` and reset.
The code-cache itself maintains the actual executable memory and
stack-unwinding code and such.

This also fixes a bunch of errornous relative-addressing glitches where
relative addresses were calculated based on the address of the unused
CodeBlock rather than being position-independent. `MOVP2R` in particular
was generating different instructions depending on its distance from the
code block when it should always just use `MOV` and not do any
relative-address calculations since we can't predict where the actual
instruction's offset will be(we cannot predict what the program counter
will be). Oaknut probably needs a "position independent" policy or mode
or something so that it avoids PC-relative instructions.
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@Wunkolo
Wunkolo committed Jun 8, 2024
1 parent d926928 commit 54790a4
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Showing 4 changed files with 36 additions and 37 deletions.
33 changes: 15 additions & 18 deletions src/xenia/cpu/backend/a64/a64_emitter.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -58,8 +58,6 @@ using xe::cpu::hir::Instr;
using namespace xe::literals;
using namespace oaknut::util;

static const size_t kMaxCodeSize = 1_MiB;

static const size_t kStashOffset = 32;
// static const size_t kStashOffsetHigh = 32 + 32;

Expand All @@ -73,8 +71,7 @@ const uint8_t A64Emitter::fpr_reg_map_[A64Emitter::FPR_COUNT] = {
};

A64Emitter::A64Emitter(A64Backend* backend)
: CodeBlock(kMaxCodeSize),
CodeGenerator(CodeBlock::ptr()),
: VectorCodeGenerator(assembly_buffer),
processor_(backend->processor()),
backend_(backend),
code_cache_(backend->code_cache()) {
Expand Down Expand Up @@ -138,23 +135,22 @@ bool A64Emitter::Emit(GuestFunction* function, HIRBuilder* builder,
void* A64Emitter::Emplace(const EmitFunctionInfo& func_info,
GuestFunction* function) {
// Copy the current oaknut instruction-buffer into the code-cache
uint32_t* old_address = CodeBlock::ptr();
void* new_execute_address;
void* new_write_address;

assert_true(func_info.code_size.total == offset());

if (function) {
code_cache_->PlaceGuestCode(function->address(), CodeBlock::ptr(),
code_cache_->PlaceGuestCode(function->address(), assembly_buffer.data(),
func_info, function, new_execute_address,
new_write_address);
} else {
code_cache_->PlaceHostCode(0, CodeBlock::ptr(), func_info,
code_cache_->PlaceHostCode(0, assembly_buffer.data(), func_info,
new_execute_address, new_write_address);
}

// Reset the oaknut instruction-buffer
set_wptr(reinterpret_cast<uint32_t*>(old_address));
assembly_buffer.clear();
label_lookup_.clear();

return new_execute_address;
Expand Down Expand Up @@ -224,7 +220,8 @@ bool A64Emitter::Emit(HIRBuilder* builder, EmitFunctionInfo& func_info) {

// Call count.
MOV(W0, 1);
MOVP2R(X5, low_address(&trace_header->function_call_count));
MOV(X5, reinterpret_cast<uintptr_t>(
low_address(&trace_header->function_call_count)));
LDADDAL(X0, X0, X5);

// Get call history slot.
Expand All @@ -234,16 +231,17 @@ bool A64Emitter::Emit(HIRBuilder* builder, EmitFunctionInfo& func_info) {
AND(W0, W0, 0b00000011);

// Record call history value into slot (guest addr in W1).
MOV(X5, uint32_t(
uint64_t(low_address(&trace_header->function_caller_history))));
MOV(X5, reinterpret_cast<uintptr_t>(
low_address(&trace_header->function_caller_history)));
STR(W1, X5, X0, oaknut::IndexExt::LSL, 2);

// Calling thread. Load X0 with thread ID.
EmitGetCurrentThreadId();
MOV(W5, 1);
LSL(W0, W5, W0);

MOVP2R(X5, low_address(&trace_header->function_thread_use));
MOV(X5, reinterpret_cast<uintptr_t>(
low_address(&trace_header->function_thread_use)));
LDSET(W0, WZR, X5);
}

Expand Down Expand Up @@ -334,8 +332,9 @@ void A64Emitter::MarkSourceOffset(const Instr* i) {
const uint32_t instruction_index =
(entry->guest_address - trace_data_->start_address()) / 4;
MOV(X0, 1);
MOVP2R(X1, low_address(trace_data_->instruction_execute_counts() +
instruction_index * 8));
MOV(X1, reinterpret_cast<uintptr_t>(
low_address(trace_data_->instruction_execute_counts() +
instruction_index * 8)));
LDADDAL(X0, ZR, X1);
}
}
Expand Down Expand Up @@ -803,11 +802,9 @@ void A64Emitter::FreeConstData(uintptr_t data) {
memory::DeallocationType::kRelease);
}

std::byte* A64Emitter::GetVConstPtr() const {
return reinterpret_cast<std::byte*>(backend_->emitter_data());
}
uintptr_t A64Emitter::GetVConstPtr() const { return backend_->emitter_data(); }

std::byte* A64Emitter::GetVConstPtr(VConst id) const {
uintptr_t A64Emitter::GetVConstPtr(VConst id) const {
// Load through fixed constant table setup by PlaceConstData.
// It's important that the pointer is not signed, as it will be sign-extended.
return GetVConstPtr() + GetVConstOffset(id);
Expand Down
8 changes: 5 additions & 3 deletions src/xenia/cpu/backend/a64/a64_emitter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -122,7 +122,7 @@ enum A64EmitterFeatureFlags {
kA64EmitF16C = 1 << 1,
};

class A64Emitter : public oaknut::CodeBlock, public oaknut::CodeGenerator {
class A64Emitter : public oaknut::VectorCodeGenerator {
public:
A64Emitter(A64Backend* backend);
virtual ~A64Emitter();
Expand Down Expand Up @@ -203,8 +203,8 @@ class A64Emitter : public oaknut::CodeBlock, public oaknut::CodeGenerator {
static bool ConstantFitsIn32Reg(uint64_t v);
void MovMem64(const oaknut::XRegSp& addr, intptr_t offset, uint64_t v);

std::byte* GetVConstPtr() const;
std::byte* GetVConstPtr(VConst id) const;
uintptr_t GetVConstPtr() const;
uintptr_t GetVConstPtr(VConst id) const;
static constexpr uintptr_t GetVConstOffset(VConst id) {
return sizeof(vec128_t) * id;
}
Expand Down Expand Up @@ -239,6 +239,8 @@ class A64Emitter : public oaknut::CodeBlock, public oaknut::CodeGenerator {
A64CodeCache* code_cache_ = nullptr;
uint32_t feature_flags_ = 0;

std::vector<std::uint32_t> assembly_buffer;

oaknut::Label* epilog_label_ = nullptr;

// Convert from plain-text label-names into oaknut-labels
Expand Down
30 changes: 15 additions & 15 deletions src/xenia/cpu/backend/a64/a64_seq_vector.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -83,10 +83,10 @@ struct LOAD_VECTOR_SHL_I8
if (i.src1.is_constant) {
auto sh = i.src1.constant();
assert_true(sh < xe::countof(lvsl_table));
e.MOVP2R(X0, &lvsl_table[sh]);
e.MOV(X0, reinterpret_cast<uintptr_t>(&lvsl_table[sh]));
e.LDR(i.dest, X0);
} else {
e.MOVP2R(X0, lvsl_table);
e.MOV(X0, reinterpret_cast<uintptr_t>(lvsl_table));
e.AND(X1, i.src1.reg().toX(), 0xf);
e.LDR(i.dest, X0, X1, IndexExt::LSL, 4);
}
Expand Down Expand Up @@ -121,10 +121,10 @@ struct LOAD_VECTOR_SHR_I8
if (i.src1.is_constant) {
auto sh = i.src1.constant();
assert_true(sh < xe::countof(lvsr_table));
e.MOVP2R(X0, &lvsr_table[sh]);
e.MOV(X0, reinterpret_cast<uintptr_t>(&lvsr_table[sh]));
e.LDR(i.dest, X0);
} else {
e.MOVP2R(X0, lvsr_table);
e.MOV(X0, reinterpret_cast<uintptr_t>(lvsr_table));
e.AND(X1, i.src1.reg().toX(), 0xf);
e.LDR(i.dest, X0, X1, IndexExt::LSL, 4);
}
Expand Down Expand Up @@ -1007,7 +1007,7 @@ struct EXTRACT_I32
e.AND(X0, i.src2.reg().toX(), 0b11);
e.LSL(X0, X0, 4);

e.MOVP2R(X1, extract_table_32);
e.MOV(X1, reinterpret_cast<uintptr_t>(extract_table_32));
e.LDR(Q0, X1, X0);

// Byte-table lookup
Expand Down Expand Up @@ -1335,7 +1335,7 @@ struct PACK : Sequence<PACK, I<OPCODE_PACK, V128Op, V128Op, V128Op>> {
}

const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

// Saturate to [3,3....] so that only values between 3...[00] and 3...[FF]
// are valid - max before min to pack NaN as zero (5454082B is heavily
Expand Down Expand Up @@ -1435,7 +1435,7 @@ struct PACK : Sequence<PACK, I<OPCODE_PACK, V128Op, V128Op, V128Op>> {
e.LoadConstantV(src, i.src1.constant());
}
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

// Saturate
e.LDR(Q1, VConstData, e.GetVConstOffset(VPackSHORT_Min));
Expand All @@ -1456,7 +1456,7 @@ struct PACK : Sequence<PACK, I<OPCODE_PACK, V128Op, V128Op, V128Op>> {
e.LoadConstantV(src, i.src1.constant());
}
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

// Saturate
e.LDR(Q1, VConstData, e.GetVConstOffset(VPackSHORT_Min));
Expand All @@ -1478,7 +1478,7 @@ struct PACK : Sequence<PACK, I<OPCODE_PACK, V128Op, V128Op, V128Op>> {
e.LoadConstantV(src, i.src1.constant());
}
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

// Saturate.
e.LDR(Q1, VConstData, e.GetVConstOffset(VPackUINT_2101010_MinUnpacked));
Expand Down Expand Up @@ -1519,7 +1519,7 @@ struct PACK : Sequence<PACK, I<OPCODE_PACK, V128Op, V128Op, V128Op>> {
e.LoadConstantV(src, i.src1.constant());
}
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

// Saturate.
e.LDR(Q1, VConstData, e.GetVConstOffset(VPackULONG_4202020_MinUnpacked));
Expand Down Expand Up @@ -1740,7 +1740,7 @@ struct UNPACK : Sequence<UNPACK, I<OPCODE_UNPACK, V128Op, V128Op>> {
static void EmitD3DCOLOR(A64Emitter& e, const EmitArgType& i) {
// ARGB (WXYZ) -> RGBA (XYZW)
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

QReg src(0);

Expand Down Expand Up @@ -1849,7 +1849,7 @@ struct UNPACK : Sequence<UNPACK, I<OPCODE_UNPACK, V128Op, V128Op>> {
// (VD.w) = 1.0 (games splat W after unpacking to get vectors of 1.0f)
// src is (xx,xx,xx,VALUE)
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

QReg src(0);
if (i.src1.is_constant) {
Expand Down Expand Up @@ -1892,7 +1892,7 @@ struct UNPACK : Sequence<UNPACK, I<OPCODE_UNPACK, V128Op, V128Op>> {
// src is (xx,xx,VALUE,VALUE)

const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

QReg src(0);
if (i.src1.is_constant) {
Expand Down Expand Up @@ -1928,7 +1928,7 @@ struct UNPACK : Sequence<UNPACK, I<OPCODE_UNPACK, V128Op, V128Op>> {
}
static void EmitUINT_2101010(A64Emitter& e, const EmitArgType& i) {
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

QReg src(0);
if (i.src1.is_constant) {
Expand Down Expand Up @@ -1972,7 +1972,7 @@ struct UNPACK : Sequence<UNPACK, I<OPCODE_UNPACK, V128Op, V128Op>> {
}
static void EmitULONG_4202020(A64Emitter& e, const EmitArgType& i) {
const XReg VConstData = X3;
e.MOVP2R(VConstData, e.GetVConstPtr());
e.MOV(VConstData, e.GetVConstPtr());

QReg src(0);
if (i.src1.is_constant) {
Expand Down
2 changes: 1 addition & 1 deletion src/xenia/cpu/backend/a64/a64_sequences.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -2758,7 +2758,7 @@ struct SET_ROUNDING_MODE_I32
e.AND(W1, i.src1, 0b111);

// Use the low 3 bits as an index into a LUT
e.MOVP2R(X0, fpcr_table);
e.MOV(X0, reinterpret_cast<uintptr_t>(fpcr_table));
e.LDRB(W0, X0, X1);

// Replace FPCR bits with new value
Expand Down

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