Revert "gdbserver: update target description creation for x86/linux"

This reverts commit 61bb321605.

gdbserver/linux-x86-tdesc.h

@@ -21,30 +21,29 @@
 #ifndef GDBSERVER_LINUX_X86_TDESC_H
 #define GDBSERVER_LINUX_X86_TDESC_H
 
-/* Convert an xcr0 value into an integer.  The integer will be passed to
-   the in-process-agent where it will then be passed to
-   x86_linux_tdesc_idx_to_xcr0 to get back the xcr0 value.  */
+/* Note: since IPA obviously knows what ABI it's running on (i386 vs x86_64
+   vs x32), it's sufficient to pass only the register set here.  This,
+   together with the ABI known at IPA compile time, maps to a tdesc.  */
 
-extern int x86_linux_xcr0_to_tdesc_idx (uint64_t xcr0);
+enum x86_linux_tdesc {
+  X86_TDESC_MMX = 0,
+  X86_TDESC_SSE = 1,
+  X86_TDESC_AVX = 2,
+  X86_TDESC_MPX = 3,
+  X86_TDESC_AVX_MPX = 4,
+  X86_TDESC_AVX_AVX512 = 5,
+  X86_TDESC_AVX_MPX_AVX512_PKU = 6,
+  X86_TDESC_LAST = 7,
+};
 
-#ifdef IN_PROCESS_AGENT
+#if defined __i386__ || !defined IN_PROCESS_AGENT
+int i386_get_ipa_tdesc_idx (const struct target_desc *tdesc);
+#endif
 
-/* Convert an index number (as returned from x86_linux_xcr0_to_tdesc_idx)
-   into an xcr0 value which can then be used to create a target
-   description.  */
+#if defined __x86_64__ && !defined IN_PROCESS_AGENT
+int amd64_get_ipa_tdesc_idx (const struct target_desc *tdesc);
+#endif
 
-extern uint64_t x86_linux_tdesc_idx_to_xcr0 (int idx);
-
-/* Within the in-process-agent we need to pre-initialise all of the target
-   descriptions, to do this we need to know how many target descriptions
-   there are for each different target type.  These functions return the
-   target description count for the relevant target.  */
-
-extern int x86_linux_amd64_ipa_tdesc_count ();
-extern int x86_linux_x32_ipa_tdesc_count ();
-extern int x86_linux_i386_ipa_tdesc_count ();
-
-
-#endif /* IN_PROCESS_AGENT */
+const struct target_desc *i386_get_ipa_tdesc (int idx);
 
 #endif /* GDBSERVER_LINUX_X86_TDESC_H */