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Commit 3ba2f86a authored May 17, 2018 by Chris Forbes

Switch x86/x64 trampolines to use attribute((naked))

Switching to clang++ means __attribute__((optimize)) is no longer
recognized. However, we do get __attribute__((naked)).

Slightly larger change than I'd like because __attribute__((naked))
doesn't permit C variable declarations.

Change-Id: I558ccaf292e381d33e10c5034053cdc651eff5f2
Bug: b/79574249
Test: TBC

parent 1236c388

opengl/libs/EGL/getProcAddress.cpp

+20 −22

Original line number	Diff line number	Diff line
		@@ -80,46 +80,44 @@ namespace android {

		#elif defined(__i386__)

		#define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
		#define API_ENTRY(_api) __attribute__((naked)) _api

		#define CALL_GL_EXTENSION_API(_api) \
		register void** fn; \
		__asm__ volatile( \
		"mov %%gs:0, %[fn]\n" \
		"mov %P[tls](%[fn]), %[fn]\n" \
		"test %[fn], %[fn]\n" \
		"cmovne %P[api](%[fn]), %[fn]\n" \
		"test %[fn], %[fn]\n" \
		"mov %%gs:0, %%eax\n" \
		"mov %P[tls](%%eax), %%eax\n" \
		"test %%eax, %%eax\n" \
		"cmovne %P[api](%%eax), %%eax\n" \
		"test %%eax, %%eax\n" \
		"je 1f\n" \
		"jmp *%[fn]\n" \
		"1:\n" \
		: [fn] "=r" (fn) \
		"jmp *%%eax\n" \
		"1: ret\n" \
		: \
		: [tls] "i" (TLS_SLOT_OPENGL_APIsizeof(void)), \
		[api] "i" (__builtin_offsetof(gl_hooks_t, \
		ext.extensions[_api])) \
		: "cc" \
		: "eax", "cc" \
		);

		#elif defined(__x86_64__)

		#define API_ENTRY(_api) __attribute__((noinline,optimize("omit-frame-pointer"))) _api
		#define API_ENTRY(_api) __attribute__((naked)) _api

		#define CALL_GL_EXTENSION_API(_api) \
		register void** fn; \
		__asm__ volatile( \
		"mov %%fs:0, %[fn]\n" \
		"mov %P[tls](%[fn]), %[fn]\n" \
		"test %[fn], %[fn]\n" \
		"cmovne %P[api](%[fn]), %[fn]\n" \
		"test %[fn], %[fn]\n" \
		"mov %%fs:0, %%rax\n" \
		"mov %P[tls](%%rax), %%rax\n" \
		"test %%rax, %%rax\n" \
		"cmovne %P[api](%%rax), %%rax\n" \
		"test %%rax, %%rax\n" \
		"je 1f\n" \
		"jmp *%[fn]\n" \
		"1:\n" \
		: [fn] "=r" (fn) \
		"jmp *%%rax\n" \
		"1: ret\n" \
		: \
		: [tls] "i" (TLS_SLOT_OPENGL_APIsizeof(void)), \
		[api] "i" (__builtin_offsetof(gl_hooks_t, \
		ext.extensions[_api])) \
		: "cc" \
		: "rax", "cc" \
		);

		#elif defined(__mips64)