diff options
Diffstat (limited to 'contrib/llvm-project/compiler-rt/lib/builtins/hexagon/common_entry_exit_abi1.S')
-rw-r--r-- | contrib/llvm-project/compiler-rt/lib/builtins/hexagon/common_entry_exit_abi1.S | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/hexagon/common_entry_exit_abi1.S b/contrib/llvm-project/compiler-rt/lib/builtins/hexagon/common_entry_exit_abi1.S new file mode 100644 index 000000000000..23fed01c6eef --- /dev/null +++ b/contrib/llvm-project/compiler-rt/lib/builtins/hexagon/common_entry_exit_abi1.S @@ -0,0 +1,102 @@ +//===----------------------Hexagon builtin routine ------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// + +// Functions that implement common sequences in function prologues and epilogues +// used to save code size + + .macro FUNCTION_BEGIN name + .text + .globl \name + .type \name, @function + .falign +\name: + .endm + + .macro FUNCTION_END name + .size \name, . - \name + .endm + + .macro FALLTHROUGH_TAIL_CALL name0 name1 + .size \name0, . - \name0 + .globl \name1 + .type \name1, @function + .falign +\name1: + .endm + + + + +// Save r25:24 at fp+#-8 and r27:26 at fp+#-16. + + + + +// The compiler knows that the __save_* functions clobber LR. No other +// registers should be used without informing the compiler. + +// Since we can only issue one store per packet, we don't hurt performance by +// simply jumping to the right point in this sequence of stores. + +FUNCTION_BEGIN __save_r24_through_r27 + memd(fp+#-16) = r27:26 +FALLTHROUGH_TAIL_CALL __save_r24_through_r27 __save_r24_through_r25 + { + memd(fp+#-8) = r25:24 + jumpr lr + } +FUNCTION_END __save_r24_through_r25 + + + + +// For each of the *_before_tailcall functions, jumpr lr is executed in parallel +// with deallocframe. That way, the return gets the old value of lr, which is +// where these functions need to return, and at the same time, lr gets the value +// it needs going into the tail call. + +FUNCTION_BEGIN __restore_r24_through_r27_and_deallocframe_before_tailcall + r27:26 = memd(fp+#-16) +FALLTHROUGH_TAIL_CALL __restore_r24_through_r27_and_deallocframe_before_tailcall __restore_r24_through_r25_and_deallocframe_before_tailcall + { + r25:24 = memd(fp+#-8) + deallocframe + jumpr lr + } +FUNCTION_END __restore_r24_through_r25_and_deallocframe_before_tailcall + + + + +// Here we use the extra load bandwidth to restore LR early, allowing the return +// to occur in parallel with the deallocframe. + +FUNCTION_BEGIN __restore_r24_through_r27_and_deallocframe + { + lr = memw(fp+#4) + r27:26 = memd(fp+#-16) + } + { + r25:24 = memd(fp+#-8) + deallocframe + jumpr lr + } +FUNCTION_END __restore_r24_through_r27_and_deallocframe + + + + +// Here the load bandwidth is maximized. + +FUNCTION_BEGIN __restore_r24_through_r25_and_deallocframe + { + r25:24 = memd(fp+#-8) + deallocframe + } + jumpr lr +FUNCTION_END __restore_r24_through_r25_and_deallocframe |