[Feat, Test] (MG_Impl, MG_State, MG_Util): opt-in MOBILEGL_ASYNC_OPTIMISTIC_SHADER_STATUS - shader compile status/log answer without joining, latched per compile

MobileGL/MG_State/GLState/ProgramState/ProgramLinkTask.cpp

@@ -408,6 +408,13 @@ namespace MobileGL::MG_State::GLState {
                     MG_Util::ConvertGLEnumToString(shaderType).c_str());
 
             if (!compiled.compileStatus) {
+                // The compile log LEADS the quoted source, and that order is load-bearing:
+                // under MOBILEGL_ASYNC_OPTIMISTIC_SHADER_STATUS this string is the
+                // application's ONLY compile diagnostic (the per-shader queries answered
+                // optimistically), and applications read it through a bounded buffer -
+                // Iris uses 32768 bytes - so the actionable text must come before the
+                // potentially-100KB source dump. The full source stays: the device log is
+                // where a failing pack gets debugged from.
                 artifacts.infoLog =
                     std::format("Linking a {} with compilation error, linking will now terminate. Shader error "
                                 "log:\n{}\nShader src:\n{}",

MobileGL/MG_State/GLState/ProgramState/ShaderObject.cpp

@@ -88,12 +88,19 @@ namespace MobileGL::MG_State::GLState {
         // another object, THIS object has not pulled its result yet. (An adopted node may
         // already be terminal - the join then only replays what is left of its diagnostics.)
         m_compileJoined = false;
+        // A new compile is a new story: whatever the optimistic getters promised about the
+        // previous node does not carry over.
+        m_optimisticAnswerLatched = false;
     }
 
     void ShaderObject::DropCompileNode() const {
         if (!m_compiled) return;
         m_compiled->ReleaseAdopter();
         m_compiled.reset();
+        // No node means IsCompileComplete() is trivially true and the truthful answers are
+        // "not compiled"; a stale latch would keep reporting a compile that no longer
+        // exists as GL_TRUE.
+        m_optimisticAnswerLatched = false;
     }
 
     void ShaderObject::InvalidateCompiledState() {

MobileGL/MG_State/GLState/ProgramState/ShaderObject.h

@@ -116,8 +116,10 @@ namespace MobileGL {
             Bool GetDeleteStatus() const { return m_deleteStatus; }
 
             // Blocks until a pending compile has published its artifacts. Public for the
-            // sites that must join without reading anything - ProgramObject::Link's
-            // prologue, which needs every attached shader settled before it runs.
+            // sites that must join without reading anything - ProgramState::
+            // JoinAllPendingWork, the glMaxShaderCompilerThreadsKHR(0) path that settles
+            // every outstanding job. glLinkProgram deliberately does NOT come through
+            // here: its prologue takes the nodes unjoined via CompiledNodeForLink().
             void JoinCompile() const { EnsureCompileJoined(); }
 
             // True while this object holds the outcome (success OR failure) of a Compile()
@@ -141,6 +143,23 @@ namespace MobileGL {
             // outstanding to wait for.
             Bool IsCompileComplete() const { return m_compiled == nullptr || m_compiled->IsTerminal(); }
 
+            // MOBILEGL_ASYNC_OPTIMISTIC_SHADER_STATUS's one-story-per-compile memory. The
+            // three optimistic getter sites in GL_Program ask THIS instead of a raw
+            // IsCompileComplete() peek, and the difference is the latch: without it, a job
+            // that settles between two adjacent queries hands the application a torn pair -
+            // an empty info log from the optimistic read, then the real GL_FALSE from the
+            // truthful one - and an application that aborts on that status never reaches
+            // the link join that quotes the real log. So the first optimistic answer
+            // latches: until the next AdoptCompileNode/DropCompileNode this object keeps
+            // answering optimistically even after the job settles, and a real failure
+            // surfaces exactly once, at the link. Returns whether the caller should answer
+            // optimistically; the caller has already checked the quirk is active.
+            Bool TakeOptimisticCompileAnswer() const {
+                if (!m_optimisticAnswerLatched && IsCompileComplete()) return false;
+                m_optimisticAnswerLatched = true;
+                return true;
+            }
+
         private:
             // ---- The one and only join gate for compile output (P1 invariant I5) ----
             // The fast path - no job, or a job whose result this object has already pulled -
@@ -231,6 +250,10 @@ namespace MobileGL {
             // Exactly-once latch for the pull above. Armed with every new job node, set by
             // the one join that consumes it.
             mutable Bool m_compileJoined = false;
+            // TakeOptimisticCompileAnswer's memory: this object has answered a compile
+            // query optimistically for the current node. Cleared wherever the node
+            // changes hands (AdoptCompileNode) or goes away (DropCompileNode).
+            mutable Bool m_optimisticAnswerLatched = false;
         };
     } // namespace MG_State::GLState
 } // namespace MobileGL