decomp: allow skipping inline-asm from output

decompiler/IR2/OpenGoalMapping.cpp

@@ -8,6 +8,14 @@ typedef OpenGOALAsm::InstructionModifiers MOD;
 
 const std::map<InstructionKind, OpenGOALAsm::Function> MIPS_ASM_TO_OPEN_GOAL_FUNCS = {
     // ----- EE -------
+    // Instructions that are nopped
+    {InstructionKind::MTC0, {".nop", {MOD::SKIP_IT}}}, // they only use this for performance counters / Count / Debug
+    {InstructionKind::MTPC, {".nop", {MOD::SKIP_IT}}},
+    {InstructionKind::MFPC, {".nop", {MOD::SKIP_IT}}},
+    {InstructionKind::SYNCP, {".nop", {MOD::SKIP_IT}}},
+    {InstructionKind::SYNCL, {".nop", {MOD::SKIP_IT}}},
+
+    // Shifts and such
     {InstructionKind::PSLLW, {".pw.sll", {}}},
     {InstructionKind::PSRAW, {".pw.sra", {}}},
     {InstructionKind::PSUBW, {".psubw", {}}},
@@ -152,6 +160,10 @@ OpenGOALAsm::OpenGOALAsm(Instruction _instr) : instr(_instr) {
     if (func.funcTemplate.rfind("TODO", 0) == 0) {
       todo = true;
     }
+    if (std::find(func.modifiers.begin(), func.modifiers.end(), InstructionModifiers::SKIP_IT) !=
+        func.modifiers.end()) {
+      skip = true;
+    }
   }
 }
 
@@ -166,6 +178,10 @@ OpenGOALAsm::OpenGOALAsm(Instruction _instr,
     if (func.funcTemplate.rfind("TODO", 0) == 0) {
       todo = true;
     }
+    if (std::find(func.modifiers.begin(), func.modifiers.end(), InstructionModifiers::SKIP_IT) !=
+        func.modifiers.end()) {
+      skip = true;
+    }
   }
 }
 

decompiler/IR2/OpenGoalMapping.h

@@ -22,7 +22,8 @@ struct OpenGOALAsm {
     FSF,
     OFFSET,
     SWAP_FIRST_TWO_SOURCE_ARGS,
-    ACC_THIRD_SRC_ARG
+    ACC_THIRD_SRC_ARG,
+    SKIP_IT
   };
 
   struct Function {
@@ -40,6 +41,7 @@ struct OpenGOALAsm {
 
   bool valid = true;
   bool todo = false;
+  bool skip = false;
   Instruction instr;
   std::optional<RegisterAccess> m_dst;
   std::vector<std::optional<RegisterAccess>> m_src;

decompiler/analysis/inline_asm_rewrite.cpp

@@ -45,6 +45,8 @@ bool rewrite_inline_asm_instructions(Form* top_level_form,
                                      asmOp.instr.to_string(f.ir2.env.file->labels));
           new_entries.push_back(entry);
           continue;
+        } else if (asmOp.skip) {
+          continue;
         } else if (elem->op()->instruction().kind == InstructionKind::VOPMULA) {
           // So far, the only instruction we deal with in pairs is the outer-product
           // This is kinda a hack, internally the src args of VOPMSUB will be swapped which is