[dynarmic] allow better dtrace diagnostics for code - do not clobber %rbp and save frame pointer (#2653)

Saving the %rbp pointer allows us to backref previous stackframes easily

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/2653
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>
Reviewed-by: Caio Oliveira <caiooliveirafarias0@gmail.com>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

.gitignore

@@ -37,6 +37,8 @@ CMakeLists.txt.user*
 # *nix related
 # Common convention for backup or temporary files
 *~
+*.core
+dtrace-out/
 
 # Visual Studio CMake settings
 CMakeSettings.json

src/dynarmic/src/dynarmic/backend/x64/a32_emit_x64.cpp

@@ -217,13 +217,13 @@ void A32EmitX64::ClearFastDispatchTable() {
 }
 
 void A32EmitX64::GenTerminalHandlers() {
-    // PC ends up in ebp, location_descriptor ends up in rbx
+    // PC ends up in edi, location_descriptor ends up in rbx
     const auto calculate_location_descriptor = [this] {
         // This calculation has to match up with IREmitter::PushRSB
         code.mov(ebx, dword[code.ABI_JIT_PTR + offsetof(A32JitState, upper_location_descriptor)]);
         code.shl(rbx, 32);
         code.mov(ecx, MJitStateReg(A32::Reg::PC));
-        code.mov(ebp, ecx);
+        code.mov(edi, ecx);
         code.or_(rbx, rcx);
     };
 
@@ -238,7 +238,7 @@ void A32EmitX64::GenTerminalHandlers() {
     code.mov(dword[code.ABI_JIT_PTR + offsetof(A32JitState, rsb_ptr)], eax);
     code.cmp(rbx, qword[code.ABI_JIT_PTR + offsetof(A32JitState, rsb_location_descriptors) + rax * sizeof(u64)]);
     if (conf.HasOptimization(OptimizationFlag::FastDispatch)) {
-        code.jne(rsb_cache_miss);
+        code.jne(rsb_cache_miss, code.T_NEAR);
     } else {
         code.jne(code.GetReturnFromRunCodeAddress());
     }
@@ -251,20 +251,21 @@ void A32EmitX64::GenTerminalHandlers() {
         terminal_handler_fast_dispatch_hint = code.getCurr<const void*>();
         calculate_location_descriptor();
         code.L(rsb_cache_miss);
-        code.mov(r12, reinterpret_cast<u64>(fast_dispatch_table.data()));
-        code.mov(rbp, rbx);
+        code.mov(r8, reinterpret_cast<u64>(fast_dispatch_table.data()));
+        //code.mov(r12d, MJitStateReg(A32::Reg::PC));
+        code.mov(r12, rbx);
         if (code.HasHostFeature(HostFeature::SSE42)) {
-            code.crc32(rbp, r12);
+            code.crc32(r12, r8);
         }
-        code.and_(ebp, fast_dispatch_table_mask);
-        code.lea(rbp, ptr[r12 + rbp]);
-        code.cmp(rbx, qword[rbp + offsetof(FastDispatchEntry, location_descriptor)]);
-        code.jne(fast_dispatch_cache_miss);
-        code.jmp(ptr[rbp + offsetof(FastDispatchEntry, code_ptr)]);
+        code.and_(r12d, fast_dispatch_table_mask);
+        code.lea(r12, ptr[r8 + r12]);
+        code.cmp(rbx, qword[r12 + offsetof(FastDispatchEntry, location_descriptor)]);
+        code.jne(fast_dispatch_cache_miss, code.T_NEAR);
+        code.jmp(ptr[r12 + offsetof(FastDispatchEntry, code_ptr)]);
         code.L(fast_dispatch_cache_miss);
-        code.mov(qword[rbp + offsetof(FastDispatchEntry, location_descriptor)], rbx);
+        code.mov(qword[r12 + offsetof(FastDispatchEntry, location_descriptor)], rbx);
         code.LookupBlock();
-        code.mov(ptr[rbp + offsetof(FastDispatchEntry, code_ptr)], rax);
+        code.mov(ptr[r12 + offsetof(FastDispatchEntry, code_ptr)], rax);
         code.jmp(rax);
         PerfMapRegister(terminal_handler_fast_dispatch_hint, code.getCurr(), "a32_terminal_handler_fast_dispatch_hint");
 

src/dynarmic/src/dynarmic/backend/x64/a64_emit_x64.cpp

@@ -188,13 +188,14 @@ void A64EmitX64::ClearFastDispatchTable() {
 }
 
 void A64EmitX64::GenTerminalHandlers() {
-    // PC ends up in rbp, location_descriptor ends up in rbx
+    // PC ends up in rcx, location_descriptor ends up in rbx
+    static_assert(std::find(ABI_ALL_CALLEE_SAVE.begin(), ABI_ALL_CALLEE_SAVE.end(), HostLoc::R12) != ABI_ALL_CALLEE_SAVE.end());
     const auto calculate_location_descriptor = [this] {
         // This calculation has to match up with A64::LocationDescriptor::UniqueHash
         // TODO: Optimization is available here based on known state of fpcr.
-        code.mov(rbp, qword[code.ABI_JIT_PTR + offsetof(A64JitState, pc)]);
+        code.mov(rdi, qword[code.ABI_JIT_PTR + offsetof(A64JitState, pc)]);
         code.mov(rcx, A64::LocationDescriptor::pc_mask);
-        code.and_(rcx, rbp);
+        code.and_(rcx, rdi);
         code.mov(ebx, dword[code.ABI_JIT_PTR + offsetof(A64JitState, fpcr)]);
         code.and_(ebx, A64::LocationDescriptor::fpcr_mask);
         code.shl(rbx, A64::LocationDescriptor::fpcr_shift);
@@ -226,20 +227,21 @@ void A64EmitX64::GenTerminalHandlers() {
         terminal_handler_fast_dispatch_hint = code.getCurr<const void*>();
         calculate_location_descriptor();
         code.L(rsb_cache_miss);
-        code.mov(r12, reinterpret_cast<u64>(fast_dispatch_table.data()));
-        code.mov(rbp, rbx);
+        code.mov(r8, reinterpret_cast<u64>(fast_dispatch_table.data()));
+        //code.mov(r12, qword[code.ABI_JIT_PTR + offsetof(A64JitState, pc)]);
+        code.mov(r12, rbx);
         if (code.HasHostFeature(HostFeature::SSE42)) {
-            code.crc32(rbp, r12);
+            code.crc32(r12, r8);
         }
-        code.and_(ebp, fast_dispatch_table_mask);
-        code.lea(rbp, ptr[r12 + rbp]);
-        code.cmp(rbx, qword[rbp + offsetof(FastDispatchEntry, location_descriptor)]);
-        code.jne(fast_dispatch_cache_miss);
-        code.jmp(ptr[rbp + offsetof(FastDispatchEntry, code_ptr)]);
+        code.and_(r12d, fast_dispatch_table_mask);
+        code.lea(r12, ptr[r8 + r12]);
+        code.cmp(rbx, qword[r12 + offsetof(FastDispatchEntry, location_descriptor)]);
+        code.jne(fast_dispatch_cache_miss, code.T_NEAR);
+        code.jmp(ptr[r12 + offsetof(FastDispatchEntry, code_ptr)]);
         code.L(fast_dispatch_cache_miss);
-        code.mov(qword[rbp + offsetof(FastDispatchEntry, location_descriptor)], rbx);
+        code.mov(qword[r12 + offsetof(FastDispatchEntry, location_descriptor)], rbx);
         code.LookupBlock();
-        code.mov(ptr[rbp + offsetof(FastDispatchEntry, code_ptr)], rax);
+        code.mov(ptr[r12 + offsetof(FastDispatchEntry, code_ptr)], rax);
         code.jmp(rax);
         PerfMapRegister(terminal_handler_fast_dispatch_hint, code.getCurr(), "a64_terminal_handler_fast_dispatch_hint");
 

src/dynarmic/src/dynarmic/backend/x64/abi.cpp

@@ -28,7 +28,8 @@ static_assert(ABI_SHADOW_SPACE <= 32);
 
 static FrameInfo CalculateFrameInfo(const size_t num_gprs, const size_t num_xmms, size_t frame_size) {
     // We are initially 8 byte aligned because the return value is pushed onto an aligned stack after a call.
-    const size_t rsp_alignment = (num_gprs % 2 == 0) ? 8 : 0;
+    // (It's an extra GPR save due to %rbp)
+    const size_t rsp_alignment = ((num_gprs + 1) % 2 == 0) ? 8 : 0;
     const size_t total_xmm_size = num_xmms * XMM_SIZE;
     if (frame_size & 0xF) {
         frame_size += 0x10 - (frame_size & 0xF);
@@ -48,6 +49,8 @@ void ABI_PushRegistersAndAdjustStack(BlockOfCode& code, const size_t frame_size,
     const size_t num_xmms = std::count_if(regs.begin(), regs.end(), HostLocIsXMM);
     const FrameInfo frame_info = CalculateFrameInfo(num_gprs, num_xmms, frame_size);
 
+    code.push(rbp);
+    code.mov(rbp, rsp);
     for (auto const gpr : regs)
         if (HostLocIsGPR(gpr))
             code.push(HostLocToReg64(gpr));
@@ -93,6 +96,7 @@ void ABI_PopRegistersAndAdjustStack(BlockOfCode& code, const size_t frame_size,
         if (HostLocIsGPR(gpr))
             code.pop(HostLocToReg64(gpr));
     }
+    code.pop(rbp);
 }
 
 void ABI_PushCalleeSaveRegistersAndAdjustStack(BlockOfCode& code, const std::size_t frame_size) {

src/dynarmic/src/dynarmic/backend/x64/block_of_code.cpp

@@ -370,7 +370,7 @@ void BlockOfCode::GenRunCode(std::function<void(BlockOfCode&)> rcp) {
 
     cmp(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], 0);
     jne(return_to_caller_mxcsr_already_exited, T_NEAR);
-    lock(); or_(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], static_cast<u32>(HaltReason::Step));
+    lock(); or_(dword[ABI_JIT_PTR + jsi.offsetof_halt_reason], u32(HaltReason::Step));
 
     SwitchMxcsrOnEntry();
     jmp(ABI_PARAM2);

src/dynarmic/tests/print_info.cpp

@@ -37,6 +37,9 @@
 #include "dynarmic/ir/basic_block.h"
 #include "dynarmic/ir/opt_passes.h"
 
+#include "./A32/testenv.h"
+#include "./A64/testenv.h"
+
 using namespace Dynarmic;
 
 std::string_view GetNameOfA32Instruction(u32 instruction) {
@@ -65,7 +68,10 @@ void PrintA32Instruction(u32 instruction) {
     fmt::print("should_continue: {}\n\n", should_continue);
     fmt::print("IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
-    Optimization::Optimize(ir_block, A32::UserConfig{}, {});
+    ArmTestEnv jit_env{};
+    Dynarmic::A32::UserConfig jit_user_config{};
+    jit_user_config.callbacks = &jit_env;
+    Optimization::Optimize(ir_block, jit_user_config, {});
     fmt::print("Optimized IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
 }
@@ -80,7 +86,10 @@ void PrintA64Instruction(u32 instruction) {
     fmt::print("should_continue: {}\n\n", should_continue);
     fmt::print("IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
-    Optimization::Optimize(ir_block, A64::UserConfig{}, {});
+    A64TestEnv jit_env{};
+    Dynarmic::A64::UserConfig jit_user_config{};
+    jit_user_config.callbacks = &jit_env;
+    Optimization::Optimize(ir_block, jit_user_config, {});
     fmt::print("Optimized IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
 }
@@ -98,7 +107,10 @@ void PrintThumbInstruction(u32 instruction) {
     fmt::print("should_continue: {}\n\n", should_continue);
     fmt::print("IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
-    Optimization::Optimize(ir_block, A32::UserConfig{}, {});
+    ThumbTestEnv jit_env{};
+    Dynarmic::A32::UserConfig jit_user_config{};
+    jit_user_config.callbacks = &jit_env;
+    Optimization::Optimize(ir_block, jit_user_config, {});
     fmt::print("Optimized IR:\n");
     fmt::print("{}\n", IR::DumpBlock(ir_block));
 }
@@ -219,7 +231,7 @@ void ExecuteA32Instruction(u32 instruction) {
                 *(iter->second) = *value;
                 fmt::print("> {} = 0x{:08x}\n", reg_name, *value);
             }
-        } else if (reg_name == "mem" || reg_name == "memory") {
+        } else if (reg_name.starts_with("m")) {
             fmt::print("address: ");
             if (const auto address = get_value()) {
                 fmt::print("value: ");
@@ -228,7 +240,7 @@ void ExecuteA32Instruction(u32 instruction) {
                     fmt::print("> mem[0x{:08x}] = 0x{:08x}\n", *address, *value);
                 }
             }
-        } else if (reg_name == "end") {
+        } else if (reg_name == "exit" || reg_name == "end" || reg_name.starts_with("q")) {
             break;
         }
     }
@@ -244,6 +256,7 @@ void ExecuteA32Instruction(u32 instruction) {
     env.MemoryWrite32(initial_pc + 4, 0xEAFFFFFE);  // B +0
 
     cpu.Run();
+    fmt::print("{}", fmt::join(cpu.Disassemble(), "\n"));
 
     fmt::print("Registers modified:\n");
     for (size_t i = 0; i < regs.size(); ++i) {

tools/dtrace-tool.sh

@@ -1,59 +0,0 @@
-#!/usr/local/bin/bash -ex
-
-# SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
-# SPDX-License-Identifier: GPL-3.0-or-later
-
-# Basic script to run dtrace sampling over the program (requires Flamegraph)
-# Usage is either running as: ./dtrace-tool.sh pid (then input the pid of the process)
-# Or just run directly with: ./dtrace-tool.sh <command>
-
-FLAMEGRAPH_DIR=".."
-fail() {
-    printf '%s\n' "$1" >&2
-    exit "${2-1}"
-}
-
-[ -f $FLAMEGRAPH_DIR/FlameGraph/stackcollapse.pl ] || fail 'Where is flamegraph?'
-#[ which dtrace ] || fail 'Needs DTrace installed'
-
-read -r "Sampling Hz [800]: " TRACE_CFG_HZ
-if [ -z "${TRACE_CFG_HZ}" ]; then
-    TRACE_CFG_HZ=800
-fi
-
-read -r "Sampling time [5] sec: " TRACE_CFG_TIME
-if [ -z "${TRACE_CFG_TIME}" ]; then
-    TRACE_CFG_TIME=5
-fi
-
-TRACE_FILE=dtrace-out.user_stacks
-TRACE_FOLD=dtrace-out.fold
-TRACE_SVG=dtrace-out.svg
-ps
-
-if [ "$1" = 'pid' ]; then
-    read -r "PID: " TRACE_CFG_PID
-    sudo echo 'Sudo!'
-else
-    if [ -f "$1" ] && [ "$1" ]; then
-    	fail 'Usage: ./tools/dtrace-profile.sh <path to program>'
-    fi
-
-    printf "Executing: "
-    echo "$@"
-    sudo echo 'Sudo!'
-    "$@" &
-    TRACE_CFG_PID=$!
-fi
-
-TRACE_PROBE="profile-${TRACE_CFG_HZ} /pid == ${TRACE_CFG_PID} && arg1/ { @[ustack()] = count(); } tick-${TRACE_CFG_TIME}s { exit(0); }"
-
-rm -- $TRACE_SVG || echo 'Skip'
-
-sudo dtrace -x ustackframes=100 -Z -n "$TRACE_PROBE" -o $TRACE_FILE 2>/dev/null || exit
-
-perl $FLAMEGRAPH_DIR/FlameGraph/stackcollapse.pl $TRACE_FILE > $TRACE_FOLD || exit
-perl $FLAMEGRAPH_DIR/FlameGraph/flamegraph.pl $TRACE_FOLD > $TRACE_SVG || exit
-
-sudo chmod 0666 $TRACE_FILE
-rm -- $TRACE_FILE $TRACE_FOLD