Switch GLES wrappers over to using Clang (and fix inline assembly).

Bug: http://b/18003438

The GLES wrapper implementations make direct calls to their underlying
function without specifying that they are retaining the original
argument register(s). This change makes the retention of these argument
registers more explicit, and then removes the LOCAL_CLANG override,
since Clang no longer optimizes the code into a bad state.

We also switch to "naked" functions, so that we control all stack layout
information. This prevents us from accidentally still corrupting
arguments on x86 (and for other functions with many parameters).

Change-Id: I37f2ef4a697373388950b41f0a292393c9fcbac7

diff --git a/opengl/libs/Android.mk b/opengl/libs/Android.mk
index f389c94..4cbca63 100644 (file)
--- a/opengl/libs/Android.mk
+++ b/opengl/libs/Android.mk
@@ -79,7 +79,6 @@ LOCAL_SRC_FILES:=             \
        GLES_CM/gl.cpp.arm      \
 #
 
-LOCAL_CLANG := false
 LOCAL_SHARED_LIBRARIES += libcutils liblog libEGL
 LOCAL_MODULE:= libGLESv1_CM
 
@@ -107,7 +106,6 @@ LOCAL_SRC_FILES:= \
        GLES2/gl2.cpp   \
 #
 
-LOCAL_CLANG := false
 LOCAL_ARM_MODE := arm
 LOCAL_SHARED_LIBRARIES += libcutils libutils liblog libEGL
 LOCAL_MODULE:= libGLESv2
@@ -135,7 +133,6 @@ LOCAL_SRC_FILES:= \
        GLES2/gl2.cpp   \
 #
 
-LOCAL_CLANG := false
 LOCAL_ARM_MODE := arm
 LOCAL_SHARED_LIBRARIES += libcutils libutils liblog libEGL
 LOCAL_MODULE:= libGLESv3

diff --git a/opengl/libs/GLES2/gl2.cpp b/opengl/libs/GLES2/gl2.cpp
index 6034a8e..6dd87c2 100644 (file)
--- a/opengl/libs/GLES2/gl2.cpp
+++ b/opengl/libs/GLES2/gl2.cpp
@@ -34,39 +34,65 @@ using namespace android;
 
 #undef API_ENTRY
 #undef CALL_GL_API
+#undef CALL_GL_API_INTERNAL_CALL
+#undef CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+#undef CALL_GL_API_INTERNAL_DO_RETURN
 #undef CALL_GL_API_RETURN
 
 #if USE_SLOW_BINDING
 
     #define API_ENTRY(_api) _api
 
-    #define CALL_GL_API(_api, ...)                                       \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                         \
         gl_hooks_t::gl_t const * const _c = &getGlThreadSpecific()->gl;  \
         if (_c) return _c->_api(__VA_ARGS__);
 
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE return 0;
+
+    // This stays blank, since void functions will implicitly return, and
+    // all of the other functions will return 0 based on the previous macro.
+    #define CALL_GL_API_INTERNAL_DO_RETURN
+
 #elif defined(__arm__)
 
     #define GET_TLS(reg) "mrc p15, 0, " #reg ", c13, c0, 3 \n"
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
-
-    #define CALL_GL_API(_api, ...)                              \
-         asm volatile(                                          \
-            GET_TLS(r12)                                        \
-            "ldr   r12, [r12, %[tls]] \n"                       \
-            "cmp   r12, #0            \n"                       \
-            "ldrne pc,  [r12, %[api]] \n"                       \
-            :                                                   \
-            : [tls] "J"(TLS_SLOT_OPENGL_API*4),                 \
-              [api] "J"(__builtin_offsetof(gl_hooks_t, gl._api))    \
-            : "r12"                                             \
-            );
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
+
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                 \
+        asm volatile(                                            \
+            GET_TLS(r12)                                         \
+            "ldr   r12, [r12, %[tls]] \n"                        \
+            "cmp   r12, #0            \n"                        \
+            "ldrne pc,  [r12, %[api]] \n"                        \
+            :                                                    \
+            : [tls] "J"(TLS_SLOT_OPENGL_API*4),                  \
+              [api] "J"(__builtin_offsetof(gl_hooks_t, gl._api)) \
+            : "r0", "r1", "r2", "r3", "r12"                      \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        asm volatile(                             \
+            "mov r0, #0 \n"                       \
+            :                                     \
+            :                                     \
+            : "r0"                                \
+        );
+
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        asm volatile(                      \
+            "bx lr \n"                     \
+            :                              \
+            :                              \
+            : "r0"                         \
+        );
 
 #elif defined(__aarch64__)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
         asm volatile(                                               \
             "mrs x16, tpidr_el0\n"                                  \
             "ldr x16, [x16, %[tls]]\n"                              \
@@ -77,121 +103,173 @@ using namespace android;
             :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API * sizeof(void*)),      \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "x16"                                                 \
+            : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", "x16" \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        asm volatile(                             \
+            "mov w0, wzr \n"                      \
+            :                                     \
+            :                                     \
+            : "w0"                                \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        asm volatile(                      \
+            "ret \n"                       \
+            :                              \
+            :                              \
+            :                              \
         );
 
 #elif defined(__i386__)
 
-    #define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
-        register void** fn;                                         \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
         __asm__ volatile(                                           \
-            "mov %%gs:0, %[fn]\n"                                   \
-            "mov %P[tls](%[fn]), %[fn]\n"                           \
-            "test %[fn], %[fn]\n"                                   \
+            "mov %%gs:0, %%eax\n"                                   \
+            "mov %P[tls](%%eax), %%eax\n"                           \
+            "test %%eax, %%eax\n"                                   \
             "je 1f\n"                                               \
-            "jmp *%P[api](%[fn])\n"                                 \
+            "jmp *%P[api](%%eax)\n"                                 \
             "1:\n"                                                  \
-            : [fn] "=r" (fn)                                        \
+            :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API*sizeof(void*)),        \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "cc"                                                  \
+            : "cc", "%eax"                                          \
             );
 
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        __asm__ volatile(                         \
+            "xor %%eax, %%eax\n"                  \
+            :                                     \
+            :                                     \
+            : "%eax"                              \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        __asm__ volatile(                  \
+            "ret\n"                        \
+            :                              \
+            :                              \
+            :                              \
+        );
+
 #elif defined(__x86_64__)
 
-    #define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
-         register void** fn;                                        \
-         __asm__ volatile(                                          \
-            "mov %%fs:0, %[fn]\n"                                   \
-            "mov %P[tls](%[fn]), %[fn]\n"                           \
-            "test %[fn], %[fn]\n"                                   \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
+        __asm__ volatile(                                           \
+            "mov %%fs:0, %%rax\n"                                   \
+            "mov %P[tls](%%rax), %%rax\n"                           \
+            "test %%rax, %%rax\n"                                   \
             "je 1f\n"                                               \
-            "jmp *%P[api](%[fn])\n"                                 \
+            "jmp *%P[api](%%rax)\n"                                 \
             "1:\n"                                                  \
-            : [fn] "=r" (fn)                                        \
+            :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API*sizeof(void*)),        \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "cc"                                                  \
-            );
+            : "cc", "%rdi", "%rsi", "%rdx", "%rcx", "%r8", "%r9",   \
+              "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", \
+              "%xmm6", "%xmm7"                                      \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        __asm__ volatile(                         \
+            "xor %%eax, %%eax\n"                  \
+            :                                     \
+            :                                     \
+            : "%eax"                              \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        __asm__ volatile(                  \
+            "retq\n"                       \
+            :                              \
+            :                              \
+            :                              \
+        );
 
 #elif defined(__mips64)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
-
-    #define CALL_GL_API(_api, ...)                            \
-    register unsigned long _t0 asm("$12");                    \
-    register unsigned long _fn asm("$25");                    \
-    register unsigned long _tls asm("$3");                    \
-    register unsigned long _v0 asm("$2");                     \
-    asm volatile(                                             \
-        ".set  push\n\t"                                      \
-        ".set  noreorder\n\t"                                 \
-        "rdhwr %[tls], $29\n\t"                               \
-        "ld    %[t0], %[OPENGL_API](%[tls])\n\t"              \
-        "beqz  %[t0], 1f\n\t"                                 \
-        " move %[fn], $ra\n\t"                                \
-        "ld    %[t0], %[API](%[t0])\n\t"                      \
-        "beqz  %[t0], 1f\n\t"                                 \
-        " nop\n\t"                                            \
-        "move  %[fn], %[t0]\n\t"                              \
-        "1:\n\t"                                              \
-        "jalr  $0, %[fn]\n\t"                                 \
-        " move %[v0], $0\n\t"                                 \
-        ".set  pop\n\t"                                       \
-        : [fn] "=c"(_fn),                                     \
-          [tls] "=&r"(_tls),                                  \
-          [t0] "=&r"(_t0),                                    \
-          [v0] "=&r"(_v0)                                     \
-        : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*sizeof(void*)),\
-          [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api))  \
-        :                                                     \
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
+
+    // t0:  $12
+    // fn:  $25
+    // tls: $3
+    // v0:  $2
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                  \
+        asm volatile(                                             \
+            ".set  push\n\t"                                      \
+            ".set  noreorder\n\t"                                 \
+            "rdhwr $3, $29\n\t"                                   \
+            "ld    $12, %[OPENGL_API]($3)\n\t"                    \
+            "beqz  $12, 1f\n\t"                                   \
+            " move $25, $ra\n\t"                                  \
+            "ld    $12, %[API]($12)\n\t"                          \
+            "beqz  $12, 1f\n\t"                                   \
+            " nop\n\t"                                            \
+            "move  $25, $12\n\t"                                  \
+            "1:\n\t"                                              \
+            "jalr  $0, $25\n\t"                                   \
+            " move $2, $0\n\t"                                    \
+            ".set  pop\n\t"                                       \
+            :                                                     \
+            : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*sizeof(void*)),\
+              [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api))  \
+            : "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$9",     \
+              "$10", "$11", "$12", "$25"                          \
         );
 
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+    #define CALL_GL_API_INTERNAL_DO_RETURN
+
 #elif defined(__mips__)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                               \
-        register unsigned int _t0 asm("$8");                     \
-        register unsigned int _fn asm("$25");                    \
-        register unsigned int _tls asm("$3");                    \
-        register unsigned int _v0 asm("$2");                     \
+    // t0:  $8
+    // fn:  $25
+    // tls: $3
+    // v0:  $2
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                 \
         asm volatile(                                            \
             ".set  push\n\t"                                     \
             ".set  noreorder\n\t"                                \
             ".set  mips32r2\n\t"                                 \
-            "rdhwr %[tls], $29\n\t"                              \
-            "lw    %[t0], %[OPENGL_API](%[tls])\n\t"             \
-            "beqz  %[t0], 1f\n\t"                                \
-            " move %[fn],$ra\n\t"                                \
-            "lw    %[t0], %[API](%[t0])\n\t"                     \
-            "beqz  %[t0], 1f\n\t"                                \
+            "rdhwr $3, $29\n\t"                                  \
+            "lw    $3, %[OPENGL_API]($3)\n\t"                    \
+            "beqz  $3, 1f\n\t"                                   \
+            " move $25,$ra\n\t"                                  \
+            "lw    $3, %[API]($3)\n\t"                           \
+            "beqz  $3, 1f\n\t"                                   \
             " nop\n\t"                                           \
-            "move  %[fn], %[t0]\n\t"                             \
+            "move  $25, $3\n\t"                                  \
             "1:\n\t"                                             \
-            "jalr  $0, %[fn]\n\t"                                \
-            " move %[v0], $0\n\t"                                \
+            "jalr  $0, $25\n\t"                                  \
+            " move $2, $0\n\t"                                   \
             ".set  pop\n\t"                                      \
-            : [fn] "=c"(_fn),                                    \
-              [tls] "=&r"(_tls),                                 \
-              [t0] "=&r"(_t0),                                   \
-              [v0] "=&r"(_v0)                                    \
+            :                                                    \
             : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*4),           \
               [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api)) \
-            :                                                    \
-            );
+            : "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$25"    \
+        );
 
-#endif
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+    #define CALL_GL_API_INTERNAL_DO_RETURN
 
-#define CALL_GL_API_RETURN(_api, ...) \
-    CALL_GL_API(_api, __VA_ARGS__) \
-    return 0;
+#endif
 
+#define CALL_GL_API(_api, ...) \
+    CALL_GL_API_INTERNAL_CALL(_api, __VA_ARGS__) \
+    CALL_GL_API_INTERNAL_DO_RETURN
 
+#define CALL_GL_API_RETURN(_api, ...) \
+    CALL_GL_API_INTERNAL_CALL(_api, __VA_ARGS__) \
+    CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+    CALL_GL_API_INTERNAL_DO_RETURN
 
 extern "C" {
 #pragma GCC diagnostic ignored "-Wunused-parameter"
@@ -202,6 +280,9 @@ extern "C" {
 
 #undef API_ENTRY
 #undef CALL_GL_API
+#undef CALL_GL_API_INTERNAL_CALL
+#undef CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+#undef CALL_GL_API_INTERNAL_DO_RETURN
 #undef CALL_GL_API_RETURN
 
 /*

diff --git a/opengl/libs/GLES_CM/gl.cpp b/opengl/libs/GLES_CM/gl.cpp
index b1b31f8..8bde4e5 100644 (file)
--- a/opengl/libs/GLES_CM/gl.cpp
+++ b/opengl/libs/GLES_CM/gl.cpp
@@ -90,39 +90,65 @@ GL_API void GL_APIENTRY glWeightPointerOESBounds(GLint size, GLenum type,
 
 #undef API_ENTRY
 #undef CALL_GL_API
+#undef CALL_GL_API_INTERNAL_CALL
+#undef CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+#undef CALL_GL_API_INTERNAL_DO_RETURN
 #undef CALL_GL_API_RETURN
 
 #if USE_SLOW_BINDING
 
     #define API_ENTRY(_api) _api
 
-    #define CALL_GL_API(_api, ...)                                       \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                         \
         gl_hooks_t::gl_t const * const _c = &getGlThreadSpecific()->gl;  \
         if (_c) return _c->_api(__VA_ARGS__);
 
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE return 0;
+
+    // This stays blank, since void functions will implicitly return, and
+    // all of the other functions will return 0 based on the previous macro.
+    #define CALL_GL_API_INTERNAL_DO_RETURN
+
 #elif defined(__arm__)
 
     #define GET_TLS(reg) "mrc p15, 0, " #reg ", c13, c0, 3 \n"
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                              \
-         asm volatile(                                          \
-            GET_TLS(r12)                                        \
-            "ldr   r12, [r12, %[tls]] \n"                       \
-            "cmp   r12, #0            \n"                       \
-            "ldrne pc,  [r12, %[api]] \n"                       \
-            :                                                   \
-            : [tls] "J"(TLS_SLOT_OPENGL_API*4),                 \
-              [api] "J"(__builtin_offsetof(gl_hooks_t, gl._api))    \
-            : "r12"                                             \
-            );
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                 \
+        asm volatile(                                            \
+            GET_TLS(r12)                                         \
+            "ldr   r12, [r12, %[tls]] \n"                        \
+            "cmp   r12, #0            \n"                        \
+            "ldrne pc,  [r12, %[api]] \n"                        \
+            :                                                    \
+            : [tls] "J"(TLS_SLOT_OPENGL_API*4),                  \
+              [api] "J"(__builtin_offsetof(gl_hooks_t, gl._api)) \
+            : "r0", "r1", "r2", "r3", "r12"                      \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        asm volatile(                             \
+            "mov r0, #0 \n"                       \
+            :                                     \
+            :                                     \
+            : "r0"                                \
+        );
+
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        asm volatile(                      \
+            "bx lr \n"                     \
+            :                              \
+            :                              \
+            : "r0"                         \
+        );
 
 #elif defined(__aarch64__)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
         asm volatile(                                               \
             "mrs x16, tpidr_el0\n"                                  \
             "ldr x16, [x16, %[tls]]\n"                              \
@@ -133,120 +159,173 @@ GL_API void GL_APIENTRY glWeightPointerOESBounds(GLint size, GLenum type,
             :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API * sizeof(void*)),      \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "x16"                                                 \
+            : "x0", "x1", "x2", "x3", "x4", "x5", "x6", "x7", "x16" \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        asm volatile(                             \
+            "mov w0, wzr \n"                      \
+            :                                     \
+            :                                     \
+            : "w0"                                \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        asm volatile(                      \
+            "ret \n"                       \
+            :                              \
+            :                              \
+            :                              \
         );
 
 #elif defined(__i386__)
 
-    #define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
-        register void* fn;                                          \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
         __asm__ volatile(                                           \
-            "mov %%gs:0, %[fn]\n"                                   \
-            "mov %P[tls](%[fn]), %[fn]\n"                           \
-            "test %[fn], %[fn]\n"                                   \
+            "mov %%gs:0, %%eax\n"                                   \
+            "mov %P[tls](%%eax), %%eax\n"                           \
+            "test %%eax, %%eax\n"                                   \
             "je 1f\n"                                               \
-            "jmp *%P[api](%[fn])\n"                                 \
+            "jmp *%P[api](%%eax)\n"                                 \
             "1:\n"                                                  \
-            : [fn] "=r" (fn)                                        \
+            :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API*sizeof(void*)),        \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "cc"                                                  \
-            );
+            : "cc", "%eax"                                          \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        __asm__ volatile(                         \
+            "xor %%eax, %%eax\n"                  \
+            :                                     \
+            :                                     \
+            : "%eax"                              \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        __asm__ volatile(                  \
+            "ret\n"                        \
+            :                              \
+            :                              \
+            :                              \
+        );
 
 #elif defined(__x86_64__)
 
-    #define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                                  \
-         register void** fn;                                        \
-         __asm__ volatile(                                          \
-            "mov %%fs:0, %[fn]\n"                                   \
-            "mov %P[tls](%[fn]), %[fn]\n"                           \
-            "test %[fn], %[fn]\n"                                   \
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                    \
+        __asm__ volatile(                                           \
+            "mov %%fs:0, %%rax\n"                                   \
+            "mov %P[tls](%%rax), %%rax\n"                           \
+            "test %%rax, %%rax\n"                                   \
             "je 1f\n"                                               \
-            "jmp *%P[api](%[fn])\n"                                 \
+            "jmp *%P[api](%%rax)\n"                                 \
             "1:\n"                                                  \
-            : [fn] "=r" (fn)                                        \
+            :                                                       \
             : [tls] "i" (TLS_SLOT_OPENGL_API*sizeof(void*)),        \
               [api] "i" (__builtin_offsetof(gl_hooks_t, gl._api))   \
-            : "cc"                                                  \
-            );
+            : "cc", "%rdi", "%rsi", "%rdx", "%rcx", "%r8", "%r9",   \
+              "%xmm0", "%xmm1", "%xmm2", "%xmm3", "%xmm4", "%xmm5", \
+              "%xmm6", "%xmm7"                                      \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+        __asm__ volatile(                         \
+            "xor %%eax, %%eax\n"                  \
+            :                                     \
+            :                                     \
+            : "%eax"                              \
+        );
+
+    #define CALL_GL_API_INTERNAL_DO_RETURN \
+        __asm__ volatile(                  \
+            "retq\n"                       \
+            :                              \
+            :                              \
+            :                              \
+        );
 
 #elif defined(__mips64)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
-
-    #define CALL_GL_API(_api, ...)                            \
-    register unsigned long _t0 asm("$12");                    \
-    register unsigned long _fn asm("$25");                    \
-    register unsigned long _tls asm("$3");                    \
-    register unsigned long _v0 asm("$2");                     \
-    asm volatile(                                             \
-        ".set  push\n\t"                                      \
-        ".set  noreorder\n\t"                                 \
-        "rdhwr %[tls], $29\n\t"                               \
-        "ld    %[t0], %[OPENGL_API](%[tls])\n\t"              \
-        "beqz  %[t0], 1f\n\t"                                 \
-        " move %[fn], $ra\n\t"                                \
-        "ld    %[t0], %[API](%[t0])\n\t"                      \
-        "beqz  %[t0], 1f\n\t"                                 \
-        " nop\n\t"                                            \
-        "move  %[fn], %[t0]\n\t"                              \
-        "1:\n\t"                                              \
-        "jalr  $0, %[fn]\n\t"                                 \
-        " move %[v0], $0\n\t"                                 \
-        ".set  pop\n\t"                                       \
-        : [fn] "=c"(_fn),                                     \
-          [tls] "=&r"(_tls),                                  \
-          [t0] "=&r"(_t0),                                    \
-          [v0] "=&r"(_v0)                                     \
-        : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*sizeof(void*)),\
-          [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api))  \
-        :                                                     \
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
+
+    // t0:  $12
+    // fn:  $25
+    // tls: $3
+    // v0:  $2
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                  \
+        asm volatile(                                             \
+            ".set  push\n\t"                                      \
+            ".set  noreorder\n\t"                                 \
+            "rdhwr $3, $29\n\t"                                   \
+            "ld    $12, %[OPENGL_API]($3)\n\t"                    \
+            "beqz  $12, 1f\n\t"                                   \
+            " move $25, $ra\n\t"                                  \
+            "ld    $12, %[API]($12)\n\t"                          \
+            "beqz  $12, 1f\n\t"                                   \
+            " nop\n\t"                                            \
+            "move  $25, $12\n\t"                                  \
+            "1:\n\t"                                              \
+            "jalr  $0, $25\n\t"                                   \
+            " move $2, $0\n\t"                                    \
+            ".set  pop\n\t"                                       \
+            :                                                     \
+            : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*sizeof(void*)),\
+              [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api))  \
+            : "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$9",     \
+              "$10", "$11", "$12", "$25"                          \
         );
 
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+    #define CALL_GL_API_INTERNAL_DO_RETURN
+
 #elif defined(__mips__)
 
-    #define API_ENTRY(_api) __attribute__((noinline)) _api
+    #define API_ENTRY(_api) __attribute__((naked,noinline)) _api
 
-    #define CALL_GL_API(_api, ...)                               \
-        register unsigned int _t0 asm("$8");                     \
-        register unsigned int _fn asm("$25");                    \
-        register unsigned int _tls asm("$3");                    \
-        register unsigned int _v0 asm("$2");                     \
+    // t0:  $8
+    // fn:  $25
+    // tls: $3
+    // v0:  $2
+    #define CALL_GL_API_INTERNAL_CALL(_api, ...)                 \
         asm volatile(                                            \
             ".set  push\n\t"                                     \
             ".set  noreorder\n\t"                                \
             ".set  mips32r2\n\t"                                 \
-            "rdhwr %[tls], $29\n\t"                              \
-            "lw    %[t0], %[OPENGL_API](%[tls])\n\t"             \
-            "beqz  %[t0], 1f\n\t"                                \
-            " move %[fn], $ra\n\t"                               \
-            "lw    %[t0], %[API](%[t0])\n\t"                     \
-            "beqz  %[t0], 1f\n\t"                                \
+            "rdhwr $3, $29\n\t"                                  \
+            "lw    $3, %[OPENGL_API]($3)\n\t"                    \
+            "beqz  $3, 1f\n\t"                                   \
+            " move $25,$ra\n\t"                                  \
+            "lw    $3, %[API]($3)\n\t"                           \
+            "beqz  $3, 1f\n\t"                                   \
             " nop\n\t"                                           \
-            "move  %[fn], %[t0]\n\t"                             \
+            "move  $25, $3\n\t"                                  \
             "1:\n\t"                                             \
-            "jalr  $0, %[fn]\n\t"                                \
-            " move %[v0], $0\n\t"                                \
+            "jalr  $0, $25\n\t"                                  \
+            " move $2, $0\n\t"                                   \
             ".set  pop\n\t"                                      \
-            : [fn] "=c"(_fn),                                    \
-              [tls] "=&r"(_tls),                                 \
-              [t0] "=&r"(_t0),                                   \
-              [v0] "=&r"(_v0)                                    \
+            :                                                    \
             : [OPENGL_API] "I"(TLS_SLOT_OPENGL_API*4),           \
               [API] "I"(__builtin_offsetof(gl_hooks_t, gl._api)) \
-            :                                                    \
-            );
+            : "$2", "$3", "$4", "$5", "$6", "$7", "$8", "$25"    \
+        );
+
+    #define CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+    #define CALL_GL_API_INTERNAL_DO_RETURN
 
 #endif
 
-#define CALL_GL_API_RETURN(_api, ...) \
-    CALL_GL_API(_api, __VA_ARGS__) \
-    return 0;
+#define CALL_GL_API(_api, ...) \
+    CALL_GL_API_INTERNAL_CALL(_api, __VA_ARGS__) \
+    CALL_GL_API_INTERNAL_DO_RETURN
 
+#define CALL_GL_API_RETURN(_api, ...) \
+    CALL_GL_API_INTERNAL_CALL(_api, __VA_ARGS__) \
+    CALL_GL_API_INTERNAL_SET_RETURN_VALUE \
+    CALL_GL_API_INTERNAL_DO_RETURN
 
 extern "C" {
 #pragma GCC diagnostic ignored "-Wunused-parameter"
@@ -257,6 +336,9 @@ extern "C" {
 
 #undef API_ENTRY
 #undef CALL_GL_API
+#undef CALL_GL_API_INTERNAL_CALL
+#undef CALL_GL_API_INTERNAL_SET_RETURN_VALUE
+#undef CALL_GL_API_INTERNAL_DO_RETURN
 #undef CALL_GL_API_RETURN
 
 /*