Fix TLS for platforms without library constructors.

Some platforms don't support constructors that get called when the
shared library gets loaded. This results in the thread-local-storage
key to never be allocated. Instead we can check if it was allocated on
each use. Also prevent creating new 'current' state if it already
exists, and avoid pthreads undefined behavior.

Bug b/25629882

Change-Id: I5e2486f88185150b976d88d0144e4d13a349eb79
Reviewed-on: https://swiftshader-review.googlesource.com/10451
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>

diff --git a/src/Common/Thread.hpp b/src/Common/Thread.hpp
index 8f6443e..f59a0d4 100644 (file)
--- a/src/Common/Thread.hpp
+++ b/src/Common/Thread.hpp
@@ -135,7 +135,7 @@ namespace sw
                        return TlsAlloc();
                #else
                        LocalStorageKey key;
-                       pthread_key_create(&key, 0);
+                       pthread_key_create(&key, NULL);
                        return key;
                #endif
        }
@@ -145,7 +145,7 @@ namespace sw
                #if defined(_WIN32)
                        TlsFree(key);
                #else
-                       pthread_key_delete(key);
+                       pthread_key_delete(key);   // Using an invalid key is an error but not undefined behavior.
                #endif
        }
 
@@ -154,7 +154,10 @@ namespace sw
                #if defined(_WIN32)
                        TlsSetValue(key, value);
                #else
-                       pthread_setspecific(key, value);
+                       if(key != TLS_OUT_OF_INDEXES)   // Avoid undefined behavior.
+                       {
+                               pthread_setspecific(key, value);
+                       }
                #endif
        }
 
@@ -163,6 +166,11 @@ namespace sw
                #if defined(_WIN32)
                        return TlsGetValue(key);
                #else
+                       if(key == TLS_OUT_OF_INDEXES)   // Avoid undefined behavior.
+                       {
+                               return nullptr;
+                       }
+
                        return pthread_getspecific(key);
                #endif
        }

diff --git a/src/OpenGL/libEGL/main.cpp b/src/OpenGL/libEGL/main.cpp
index 1df31c5..7f024d0 100644 (file)
--- a/src/OpenGL/libEGL/main.cpp
+++ b/src/OpenGL/libEGL/main.cpp
@@ -39,22 +39,31 @@ static sw::Thread::LocalStorageKey currentTLS = TLS_OUT_OF_INDEXES;
 
 namespace egl
 {
-void attachThread()
+Current *attachThread()
 {
        TRACE("()");
 
-       Current *current = new Current;
+       if(currentTLS == TLS_OUT_OF_INDEXES)
+       {
+               currentTLS = sw::Thread::allocateLocalStorageKey();
+       }
+
+       Current *current = (Current*)sw::Thread::getLocalStorage(currentTLS);
 
-       if(current)
+       if(!current)
        {
-               sw::Thread::setLocalStorage(currentTLS, current);
+               current = new Current;
 
-               current->error = EGL_SUCCESS;
-               current->API = EGL_OPENGL_ES_API;
-               current->context = nullptr;
-               current->drawSurface = nullptr;
-               current->readSurface = nullptr;
+               sw::Thread::setLocalStorage(currentTLS, current);
        }
+
+       current->error = EGL_SUCCESS;
+       current->API = EGL_OPENGL_ES_API;
+       current->context = nullptr;
+       current->drawSurface = nullptr;
+       current->readSurface = nullptr;
+
+       return current;
 }
 
 void detachThread()
@@ -82,13 +91,6 @@ CONSTRUCTOR void attachProcess()
                }
        #endif
 
-       currentTLS = sw::Thread::allocateLocalStorageKey();
-
-       if(currentTLS == TLS_OUT_OF_INDEXES)
-       {
-               return;
-       }
-
        attachThread();
 }
 
@@ -176,10 +178,10 @@ static Current *getCurrent(void)
 
        if(!current)
        {
-               attachThread();
+               current = attachThread();
        }
 
-       return (Current*)sw::Thread::getLocalStorage(currentTLS);
+       return current;
 }
 
 void setCurrentError(EGLint error)