Automatically install any CPU breakpoints in any newly-defined functions if necessary.

src/xenia/cpu/backend/backend.h

@@ -17,6 +17,7 @@
 namespace xe {
 namespace cpu {
 class Breakpoint;
+class Function;
 class GuestFunction;
 class Module;
 class Processor;
@@ -53,6 +54,7 @@ class Backend {
       Module* module, uint32_t address) = 0;
 
   virtual bool InstallBreakpoint(Breakpoint* bp) { return false; }
+  virtual bool InstallBreakpoint(Breakpoint* bp, Function* func) { return false; }
   virtual bool UninstallBreakpoint(Breakpoint* bp) { return false; }
 
  protected:

src/xenia/cpu/backend/x64/x64_backend.cc

@@ -133,7 +133,11 @@ bool X64Backend::InstallBreakpoint(Breakpoint* bp) {
     assert_true(function->is_guest());
     auto guest_function = reinterpret_cast<cpu::GuestFunction*>(function);
     auto code = guest_function->MapGuestAddressToMachineCode(bp->address());
-    assert_not_zero(code);
+    if (!code) {
+      // This should not happen.
+      assert_always();
+      return false;
+    }
 
     auto orig_bytes =
         xe::load_and_swap<uint16_t>(reinterpret_cast<void*>(code + 0x0));
@@ -145,6 +149,24 @@ bool X64Backend::InstallBreakpoint(Breakpoint* bp) {
   return true;
 }
 
+bool X64Backend::InstallBreakpoint(Breakpoint* bp, Function* func) {
+  assert_true(func->is_guest());
+  auto guest_function = reinterpret_cast<cpu::GuestFunction*>(func);
+  auto code = guest_function->MapGuestAddressToMachineCode(bp->address());
+  if (!code) {
+    assert_always();
+    return false;
+  }
+
+  // Assume we haven't already installed a breakpoint in this spot.
+  auto orig_bytes =
+      xe::load_and_swap<uint16_t>(reinterpret_cast<void*>(code + 0x0));
+  bp->backend_data().push_back({code, orig_bytes});
+
+  xe::store_and_swap<uint16_t>(reinterpret_cast<void*>(code + 0x0), 0x0F0C);
+  return true;
+}
+
 bool X64Backend::UninstallBreakpoint(Breakpoint* bp) {
   for (auto pair : bp->backend_data()) {
     xe::store_and_swap<uint16_t>(reinterpret_cast<void*>(pair.first),

src/xenia/cpu/backend/x64/x64_backend.h

@@ -63,6 +63,7 @@ class X64Backend : public Backend {
                                                      uint32_t address) override;
 
   bool InstallBreakpoint(Breakpoint* bp) override;
+  bool InstallBreakpoint(Breakpoint* bp, Function* func) override;
   bool UninstallBreakpoint(Breakpoint* bp) override;
 
  private: