Fix the callstack widget by keeping track of branches

Co-opts the interpreter to create a callstack, by
checking for branches and returns from branches.

src/citra_qt/debugger/callstack.cpp

@@ -7,69 +7,27 @@
 #include "citra_qt/debugger/callstack.h"
 
 #include "common/common_types.h"
-#include "common/symbols.h"
 
 #include "core/core.h"
-#include "core/memory.h"
 #include "core/arm/arm_interface.h"
-#include "core/arm/disassembler/arm_disasm.h"
 
 CallstackWidget::CallstackWidget(QWidget* parent): QDockWidget(parent)
 {
     ui.setupUi(this);
 
     callstack_model = new QStandardItemModel(this);
-    callstack_model->setColumnCount(4);
-    callstack_model->setHeaderData(0, Qt::Horizontal, "Stack Pointer");
-    callstack_model->setHeaderData(2, Qt::Horizontal, "Return Address");
-    callstack_model->setHeaderData(1, Qt::Horizontal, "Call Address");
-    callstack_model->setHeaderData(3, Qt::Horizontal, "Function");
+    callstack_model->setColumnCount(1);
+    callstack_model->setHeaderData(0, Qt::Horizontal, "Caller address");
     ui.treeView->setModel(callstack_model);
 }
 
 void CallstackWidget::OnDebugModeEntered()
 {
-    // Stack pointer
-    const u32 sp = Core::g_app_core->GetReg(13);
-
     Clear();
 
-    int counter = 0;
-    for (u32 addr = 0x10000000; addr >= sp; addr -= 4)
-    {
-        const u32 ret_addr = Memory::Read32(addr);
-        const u32 call_addr = ret_addr - 4; //get call address???
-
-        if (Memory::GetPointer(call_addr) == nullptr)
-            break;
-
-        /* TODO (mattvail) clean me, move to debugger interface */
-        u32 insn = Memory::Read32(call_addr);
-        if (ARM_Disasm::Decode(insn) == OP_BL)
-        {
-            std::string name;
-            // ripped from disasm
-            u8 cond = (insn >> 28) & 0xf;
-            u32 i_offset = insn & 0xffffff;
-            // Sign-extend the 24-bit offset
-            if ((i_offset >> 23) & 1)
-                i_offset |= 0xff000000;
-
-            // Pre-compute the left-shift and the prefetch offset
-            i_offset <<= 2;
-            i_offset += 8;
-            const u32 func_addr = call_addr + i_offset;
-
-            callstack_model->setItem(counter, 0, new QStandardItem(QString("0x%1").arg(addr, 8, 16, QLatin1Char('0'))));
-            callstack_model->setItem(counter, 1, new QStandardItem(QString("0x%1").arg(ret_addr, 8, 16, QLatin1Char('0'))));
-            callstack_model->setItem(counter, 2, new QStandardItem(QString("0x%1").arg(call_addr, 8, 16, QLatin1Char('0'))));
-
-            name = Symbols::HasSymbol(func_addr) ? Symbols::GetSymbol(func_addr).name : "unknown";
-            callstack_model->setItem(counter, 3, new QStandardItem(QString("%1_%2").arg(QString::fromStdString(name))
-                .arg(QString("0x%1").arg(func_addr, 8, 16, QLatin1Char('0')))));
-
-            counter++;
-        }
+    std::vector<u32> stack_trace = Core::g_app_core->GetStackTrace();
+    for (auto entry : stack_trace) {
+        callstack_model->setItem(callstack_model->rowCount(), new QStandardItem(QString("0x%1").arg(entry, 8, 16, QLatin1Char('0'))));
     }
 }
 
@@ -80,9 +38,5 @@ void CallstackWidget::OnDebugModeLeft()
 
 void CallstackWidget::Clear()
 {
-    for (int row = 0; row < callstack_model->rowCount(); row++) {
-        for (int column = 0; column < callstack_model->columnCount(); column++) {
-            callstack_model->setItem(row, column, new QStandardItem());
-        }
-    }
+    callstack_model->removeRows(0, callstack_model->rowCount());
 }

src/core/arm/arm_interface.h

@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <vector>
+
 #include "common/common_types.h"
 #include "core/arm/skyeye_common/arm_regformat.h"
 
@@ -111,6 +113,8 @@ public:
      */
     virtual void SetCP15Register(CP15Register reg, u32 value) = 0;
 
+    virtual std::vector<u32> GetStackTrace() const = 0;
+
     /**
      * Advance the CPU core by the specified number of ticks (e.g. to simulate CPU execution time)
      * @param ticks Number of ticks to advance the CPU core

src/core/arm/dyncom/arm_dyncom.cpp

@@ -72,6 +72,10 @@ void ARM_DynCom::SetCP15Register(CP15Register reg, u32 value) {
     state->CP15[reg] = value;
 }
 
+std::vector<u32> ARM_DynCom::GetStackTrace() const {
+    return state->stack_trace;
+}
+
 void ARM_DynCom::AddTicks(u64 ticks) {
     down_count -= ticks;
     if (down_count < 0)
@@ -89,12 +93,15 @@ void ARM_DynCom::ExecuteInstructions(int num_instructions) {
 }
 
 void ARM_DynCom::ResetContext(Core::ThreadContext& context, u32 stack_top, u32 entry_point, u32 arg) {
-    memset(&context, 0, sizeof(Core::ThreadContext));
+    context = Core::ThreadContext();
 
     context.cpu_registers[0] = arg;
     context.pc = entry_point;
     context.sp = stack_top;
     context.cpsr = 0x1F; // Usermode
+
+    context.stack_trace.clear();
+    context.stack_trace.reserve(128);
 }
 
 void ARM_DynCom::SaveContext(Core::ThreadContext& ctx) {
@@ -108,6 +115,8 @@ void ARM_DynCom::SaveContext(Core::ThreadContext& ctx) {
 
     ctx.fpscr = state->VFP[1];
     ctx.fpexc = state->VFP[2];
+
+    ctx.stack_trace = state->stack_trace;
 }
 
 void ARM_DynCom::LoadContext(const Core::ThreadContext& ctx) {
@@ -121,6 +130,8 @@ void ARM_DynCom::LoadContext(const Core::ThreadContext& ctx) {
 
     state->VFP[1] = ctx.fpscr;
     state->VFP[2] = ctx.fpexc;
+
+    state->stack_trace = ctx.stack_trace;
 }
 
 void ARM_DynCom::PrepareReschedule() {

src/core/arm/dyncom/arm_dyncom.h

@@ -33,6 +33,7 @@ public:
     void SetCPSR(u32 cpsr) override;
     u32 GetCP15Register(CP15Register reg) override;
     void SetCP15Register(CP15Register reg, u32 value) override;
+    std::vector<u32> GetStackTrace() const override;
 
     void AddTicks(u64 ticks) override;
 

src/core/arm/dyncom/arm_dyncom_interpreter.cpp

@@ -3816,6 +3816,11 @@ unsigned InterpreterMainLoop(ARMul_State* cpu) {
 
     #define CurrentModeHasSPSR (cpu->Mode != SYSTEM32MODE) && (cpu->Mode != USER32MODE)
     #define PC (cpu->Reg[15])
+    #define PUSH_STACK_TRACE \
+            cpu->stack_trace.emplace_back(cpu->Reg[15])
+    #define UPDATE_STACK_TRACE \
+            if (cpu->stack_trace.size() > 0 && cpu->stack_trace.back() == PC - cpu->GetInstructionSize()) \
+                cpu->stack_trace.pop_back()
 
     // GCC and Clang have a C++ extension to support a lookup table of labels. Otherwise, fallback
     // to a clunky switch statement.
@@ -3867,6 +3872,8 @@ unsigned InterpreterMainLoop(ARMul_State* cpu) {
         else
             cpu->Reg[15] &= 0xfffffffc;
 
+        UPDATE_STACK_TRACE;
+
         // Find the cached instruction cream, otherwise translate it...
         auto itr = cpu->instruction_cache.find(cpu->Reg[15]);
         if (itr != cpu->instruction_cache.end()) {
@@ -3993,6 +4000,7 @@ unsigned InterpreterMainLoop(ARMul_State* cpu) {
         if ((inst_base->cond == ConditionCode::AL) || CondPassed(cpu, inst_base->cond)) {
             bbl_inst *inst_cream = (bbl_inst *)inst_base->component;
             if (inst_cream->L) {
+                PUSH_STACK_TRACE;
                 LINK_RTN_ADDR;
             }
             SET_PC;
@@ -4049,6 +4057,8 @@ unsigned InterpreterMainLoop(ARMul_State* cpu) {
     {
         blx_inst *inst_cream = (blx_inst *)inst_base->component;
         if ((inst_base->cond == ConditionCode::AL) || CondPassed(cpu, inst_base->cond)) {
+            PUSH_STACK_TRACE;
+
             unsigned int inst = inst_cream->inst;
             if (BITS(inst, 20, 27) == 0x12 && BITS(inst, 4, 7) == 0x3) {
                 cpu->Reg[14] = (cpu->Reg[15] + cpu->GetInstructionSize());

src/core/arm/skyeye_common/armstate.h

@@ -18,6 +18,7 @@
 #pragma once
 
 #include <array>
+#include <vector>
 #include <unordered_map>
 
 #include "common/common_types.h"
@@ -239,6 +240,7 @@ public:
     // TODO(bunnei): Move this cache to a better place - it should be per codeset (likely per
     // process for our purposes), not per ARMul_State (which tracks CPU core state).
     std::unordered_map<u32, int> instruction_cache;
+    std::vector<u32> stack_trace;
 
 private:
     void ResetMPCoreCP15Registers();

src/core/core.h

@@ -5,6 +5,8 @@
 #pragma once
 
 #include <memory>
+#include <vector>
+
 #include "common/common_types.h"
 
 class ARM_Interface;
@@ -22,6 +24,8 @@ struct ThreadContext {
     u32 fpu_registers[64];
     u32 fpscr;
     u32 fpexc;
+
+    std::vector<u32> stack_trace;
 };
 
 extern std::unique_ptr<ARM_Interface> g_app_core; ///< ARM11 application core