Static tramp v5 (#624)

[platform/upstream/libffi.git] / src / arm / sysv.S

diff --git a/src/arm/sysv.S b/src/arm/sysv.S
index 74bc53f..49c561e 100644 (file)
--- a/src/arm/sysv.S
+++ b/src/arm/sysv.S
@@ -354,6 +354,53 @@ E(ARM_TYPE_STRUCT)
        cfi_endproc
 ARM_FUNC_END(ffi_closure_ret)
 
+#if defined(FFI_EXEC_STATIC_TRAMP)
+ARM_FUNC_START(ffi_closure_SYSV_alt)
+       /* See the comments above trampoline_code_table. */
+       ldr     ip, [sp, #4]                    /* Load closure in ip */
+       add     sp, sp, 8                       /* Restore the stack */
+       b       CNAME(ffi_closure_SYSV)
+ARM_FUNC_END(ffi_closure_SYSV_alt)
+
+ARM_FUNC_START(ffi_closure_VFP_alt)
+       /* See the comments above trampoline_code_table. */
+       ldr     ip, [sp, #4]                    /* Load closure in ip */
+       add     sp, sp, 8                       /* Restore the stack */
+       b       CNAME(ffi_closure_VFP)
+ARM_FUNC_END(ffi_closure_VFP_alt)
+
+/*
+ * Below is the definition of the trampoline code table. Each element in
+ * the code table is a trampoline.
+ */
+/*
+ * The trampoline uses register ip (r12). It saves the original value of ip
+ * on the stack.
+ *
+ * The trampoline has two parameters - target code to jump to and data for
+ * the target code. The trampoline extracts the parameters from its parameter
+ * block (see tramp_table_map()). The trampoline saves the data address on
+ * the stack. Finally, it jumps to the target code.
+ *
+ * The target code can choose to:
+ *
+ * - restore the value of ip
+ * - load the data address in a register
+ * - restore the stack pointer to what it was when the trampoline was invoked.
+ */
+       .align  ARM_TRAMP_MAP_SHIFT
+ARM_FUNC_START(trampoline_code_table)
+       .rept   ARM_TRAMP_MAP_SIZE / ARM_TRAMP_SIZE
+       sub     sp, sp, #8              /* Make space on the stack */
+       str     ip, [sp]                /* Save ip on stack */
+       ldr     ip, [pc, #4080]         /* Copy data into ip */
+       str     ip, [sp, #4]            /* Save data on stack */
+       ldr     pc, [pc, #4076]         /* Copy code into PC */
+       .endr
+ARM_FUNC_END(trampoline_code_table)
+       .align  ARM_TRAMP_MAP_SHIFT
+#endif /* FFI_EXEC_STATIC_TRAMP */
+
 #if FFI_EXEC_TRAMPOLINE_TABLE
 
 #ifdef __MACH__