From 7c420381d5625df7a584bc8386aeff7ebdd1b35f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Henrik=20Rydg=C3=A5rd?= <hrydgard@gmail.com>
Date: Mon, 1 May 2023 12:11:34 +0200
Subject: [PATCH] OpenGL: Some paranoia checks around failed shader generation

---
 GPU/GLES/DrawEngineGLES.cpp    | 7 ++++++-
 GPU/GLES/ShaderManagerGLES.cpp | 9 ++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/GPU/GLES/DrawEngineGLES.cpp b/GPU/GLES/DrawEngineGLES.cpp
index 1db3fabde1..b191014219 100644
--- a/GPU/GLES/DrawEngineGLES.cpp
+++ b/GPU/GLES/DrawEngineGLES.cpp
@@ -414,7 +414,11 @@ void DrawEngineGLES::DoFlush() {
 
 		ApplyDrawStateLate(result.setStencil, result.stencilValue);
 
-		shaderManager_->ApplyFragmentShader(vsid, vshader, pipelineState_, framebufferManager_->UseBufferedRendering());
+		LinkedShader *linked = shaderManager_->ApplyFragmentShader(vsid, vshader, pipelineState_, framebufferManager_->UseBufferedRendering());
+		if (!linked) {
+			// Not much we can do here. Let's skip drawing.
+			goto bail;
+		}
 
 		if (result.action == SW_DRAW_PRIMITIVES) {
 			if (result.drawIndexed) {
@@ -458,6 +462,7 @@ void DrawEngineGLES::DoFlush() {
 		decOptions_.applySkinInDecode = g_Config.bSoftwareSkinning;
 	}
 
+bail:
 	gpuStats.numFlushes++;
 	gpuStats.numDrawCalls += numDrawCalls;
 	gpuStats.numVertsSubmitted += vertexCountInDrawCalls_;
diff --git a/GPU/GLES/ShaderManagerGLES.cpp b/GPU/GLES/ShaderManagerGLES.cpp
index 7718eedcbb..22669a0392 100644
--- a/GPU/GLES/ShaderManagerGLES.cpp
+++ b/GPU/GLES/ShaderManagerGLES.cpp
@@ -76,13 +76,15 @@ LinkedShader::LinkedShader(GLRenderManager *render, VShaderID VSID, Shader *vs,
 		: render_(render), useHWTransform_(useHWTransform) {
 	PROFILE_THIS_SCOPE("shaderlink");
 
+	_assert_(vs);
+	_assert_(fs);
+
 	vs_ = vs;
 
 	std::vector<GLRShader *> shaders;
 	shaders.push_back(vs->shader);
 	shaders.push_back(fs->shader);
 
-
 	std::vector<GLRProgram::Semantic> semantics;
 	semantics.reserve(7);
 	semantics.push_back({ ATTR_POSITION, "position" });
@@ -874,6 +876,11 @@ LinkedShader *ShaderManagerGLES::ApplyFragmentShader(VShaderID VSID, Shader *vs,
 	if (ls == nullptr) {
 		_dbg_assert_(FSID.Bit(FS_BIT_FLATSHADE) == VSID.Bit(VS_BIT_FLATSHADE));
 
+		if (vs == nullptr || fs == nullptr) {
+			// Can't draw. This shouldn't really happen.
+			return nullptr;
+		}
+
 		// Check if we can link these.
 		ls = new LinkedShader(render_, VSID, vs, FSID, fs, vs->UseHWTransform());
 		ls->use(VSID);