From ca2d7e40eaab6f5278d6b70aa1f6fbae2f308aa7 Mon Sep 17 00:00:00 2001
From: wheremyfoodat <44909372+wheremyfoodat@users.noreply.github.com>
Date: Sun, 25 Aug 2024 19:34:56 +0300
Subject: [PATCH] Shader decompiler: Add support for compilation errors

---
 include/PICA/shader_decompiler.hpp  |  1 +
 src/core/PICA/shader_decompiler.cpp | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/PICA/shader_decompiler.hpp b/include/PICA/shader_decompiler.hpp
index b7bd869c..4a5cdc13 100644
--- a/include/PICA/shader_decompiler.hpp
+++ b/include/PICA/shader_decompiler.hpp
@@ -99,6 +99,7 @@ namespace PICA::ShaderGen {
 
 		API api;
 		Language language;
+		bool compilationError = false;
 
 		void compileInstruction(u32& pc, bool& finished);
 		// Compile range "range" and returns the end PC or if we're "finished" with the program (called an END instruction)
diff --git a/src/core/PICA/shader_decompiler.cpp b/src/core/PICA/shader_decompiler.cpp
index 75de4e50..2d4d2963 100644
--- a/src/core/PICA/shader_decompiler.cpp
+++ b/src/core/PICA/shader_decompiler.cpp
@@ -247,6 +247,7 @@ std::string ShaderDecompiler::decompile() {
 		return "";
 	}
 
+	compilationError = false;
 	decompiledShader = "";
 
 	switch (api) {
@@ -324,6 +325,13 @@ std::string ShaderDecompiler::decompile() {
 		}
 	}
 
+	// We allow some leeway for "compilation errors" in addition to control flow errors, in cases where eg an unimplemented instruction
+	// or an instruction that we can't emulate in GLSL is found in the instruction stream. Just like control flow errors, these return an empty string
+	// and the renderer core will decide to use CPU shaders instead
+	if (compilationError) [[unlikely]] {
+		return "";
+	}
+
 	return decompiledShader;
 }
 
@@ -707,7 +715,11 @@ void ShaderDecompiler::compileInstruction(u32& pc, bool& finished) {
 				return;
 
 			case ShaderOpcodes::NOP: break;
-			default: Helpers::panic("GLSL recompiler: Unknown opcode: %X", opcode); break;
+
+			default:
+				Helpers::warn("GLSL recompiler: Unknown opcode: %X. Falling back to CPU shaders", opcode);
+				compilationError = true;
+				break;
 		}
 	}