HLE: Revamp error handling throrough the HLE code

All service calls in the CTR OS return result codes indicating the
success or failure of the call. Previous to this commit, Citra's HLE
emulation of services and the kernel universally either ignored errors
or returned dummy -1 error codes.

This commit makes an initial effort to provide an infrastructure for
error reporting and propagation which can be use going forward to make
HLE calls accurately return errors as the original system. A few parts
of the code have been updated to use the new system where applicable.

One part of this effort is the definition of the `ResultCode` type,
which provides facilities for constructing and parsing error codes in
the structured format used by the CTR.

The `ResultVal` type builds on `ResultCode` by providing a container for
values returned by function that can report errors. It enforces that
correct error checking will be done on function returns by preventing
the use of the return value if the function returned an error code.

Currently this change is mostly internal since errors are still
suppressed on the ARM<->HLE border, as a temporary compatibility hack.
As functionality is implemented and tested this hack can be eventually
removed.

1 files changed, 15 insertions, 12 deletions

diff --git a/src/core/hle/kernel/shared_memory.cpp b/src/core/hle/kernel/shared_memory.cpp
index 7ef3e54c..b91fc98d 100644
--- a/src/core/hle/kernel/shared_memory.cpp
+++ b/src/core/hle/kernel/shared_memory.cpp
@@ -21,10 +21,10 @@ public:
      * @param wait Boolean wait set if current thread should wait as a result of sync operation
      * @return Result of operation, 0 on success, otherwise error code
      */
-    Result WaitSynchronization(bool* wait) override {
+    ResultVal<bool> WaitSynchronization() override {
         // TODO(bunnei): ImplementMe
         ERROR_LOG(OSHLE, "(UNIMPLEMENTED)");
-        return 0;
+        return UnimplementedFunction(ErrorModule::OS);
     }
 
     u32 base_address;                   ///< Address of shared memory block in RAM
@@ -67,22 +67,23 @@ Handle CreateSharedMemory(const std::string& name) {
  * @param other_permissions Memory block map other permissions (specified by SVC field)
  * @return Result of operation, 0 on success, otherwise error code
  */
-Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
+ResultCode MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
     MemoryPermission other_permissions) {
 
     if (address < Memory::SHARED_MEMORY_VADDR || address >= Memory::SHARED_MEMORY_VADDR_END) {
         ERROR_LOG(KERNEL, "cannot map handle=0x%08X, address=0x%08X outside of shared mem bounds!",
             handle, address);
-        return -1;
+        return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::Kernel,
+                ErrorSummary::InvalidArgument, ErrorLevel::Permanent);
     }
-    SharedMemory* shared_memory = Kernel::g_object_pool.GetFast<SharedMemory>(handle);
-    _assert_msg_(KERNEL, (shared_memory != nullptr), "handle 0x%08X is not valid!", handle);
+    SharedMemory* shared_memory = Kernel::g_object_pool.Get<SharedMemory>(handle);
+    if (shared_memory == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     shared_memory->base_address = address;
     shared_memory->permissions = permissions;
     shared_memory->other_permissions = other_permissions;
 
-    return 0;
+    return RESULT_SUCCESS;
 }
 
 /**
@@ -91,15 +92,17 @@ Result MapSharedMemory(u32 handle, u32 address, MemoryPermission permissions,
  * @param offset Offset from the start of the shared memory block to get pointer
  * @return Pointer to the shared memory block from the specified offset
  */
-u8* GetSharedMemoryPointer(Handle handle, u32 offset) {
-    SharedMemory* shared_memory = Kernel::g_object_pool.GetFast<SharedMemory>(handle);
-    _assert_msg_(KERNEL, (shared_memory != nullptr), "handle 0x%08X is not valid!", handle);
+ResultVal<u8*> GetSharedMemoryPointer(Handle handle, u32 offset) {
+    SharedMemory* shared_memory = Kernel::g_object_pool.Get<SharedMemory>(handle);
+    if (shared_memory == nullptr) return InvalidHandle(ErrorModule::Kernel);
 
     if (0 != shared_memory->base_address)
-        return Memory::GetPointer(shared_memory->base_address + offset);
+        return MakeResult<u8*>(Memory::GetPointer(shared_memory->base_address + offset));
 
     ERROR_LOG(KERNEL, "memory block handle=0x%08X not mapped!", handle);
-    return nullptr;
+    // TODO(yuriks): Verify error code.
+    return ResultCode(ErrorDescription::InvalidAddress, ErrorModule::Kernel,
+            ErrorSummary::InvalidState, ErrorLevel::Permanent);
 }
 
 } // namespace