tree c784393cea6d06407642adc200bebb9479d7769c
parent 84046b192e568e1a0619b72a12c7263553d9610a
author Lulu Cheng <chenglulu@loongson.cn> 1669709172 +0800
committer Lulu Cheng <chenglulu@loongson.cn> 1669777894 +0800

LoongArch: Optimize the implementation of stack check.

The old stack check was performed before the stack was dropped,
which would cause the detection tool to report a memory leak.

The current stack check scheme is as follows:

'-fstack-clash-protection':
1. When the frame->total_size is smaller than the guard page size,
   the stack is dropped according to the original scheme, and there
   is no need to perform stack detection in the prologue.
2. When frame->total_size is greater than or equal to guard page size,
   the first step to drop the stack is to drop the space required by
   the caller-save registers. This space needs to save the caller-save
   registers, so an implicit stack check is performed.
   So just need to check the rest of the stack space.

'-fstack-check':
There is no one-time stack drop and then page-by-page detection as
described in the document. It is also the same as
'-fstack-clash-protection', which is detected immediately after page drop.

It is judged that when frame->total_size is not 0, only the size required
to save the s register is dropped for the first stack down.

The test cases are referenced from aarch64.

gcc/ChangeLog:

	* config/loongarch/linux.h (STACK_CHECK_MOVING_SP):
	Define this macro to 1.
	* config/loongarch/loongarch.cc (STACK_CLASH_PROTECTION_GUARD_SIZE):
	Size of guard page.
	(loongarch_first_stack_step): Return the size of the first drop stack
	according to whether stack checking is performed.
	(loongarch_emit_probe_stack_range): Adjust the method of stack checking in prologue.
	(loongarch_output_probe_stack_range): Delete useless code.
	(loongarch_expand_prologue): Adjust the method of stack checking in prologue.
	(loongarch_option_override_internal): Enforce that interval is the same
	size as size so the mid-end does the right thing.
	* config/loongarch/loongarch.h (STACK_CLASH_MAX_UNROLL_PAGES):
	New macro decide whether to loop stack detection.

gcc/testsuite/ChangeLog:

	* lib/target-supports.exp:
	* gcc.target/loongarch/stack-check-alloca-1.c: New test.
	* gcc.target/loongarch/stack-check-alloca-2.c: New test.
	* gcc.target/loongarch/stack-check-alloca-3.c: New test.
	* gcc.target/loongarch/stack-check-alloca-4.c: New test.
	* gcc.target/loongarch/stack-check-alloca-5.c: New test.
	* gcc.target/loongarch/stack-check-alloca-6.c: New test.
	* gcc.target/loongarch/stack-check-alloca.h: New test.
	* gcc.target/loongarch/stack-check-cfa-1.c: New test.
	* gcc.target/loongarch/stack-check-cfa-2.c: New test.
	* gcc.target/loongarch/stack-check-prologue-1.c: New test.
	* gcc.target/loongarch/stack-check-prologue-2.c: New test.
	* gcc.target/loongarch/stack-check-prologue-3.c: New test.
	* gcc.target/loongarch/stack-check-prologue-4.c: New test.
	* gcc.target/loongarch/stack-check-prologue-5.c: New test.
	* gcc.target/loongarch/stack-check-prologue-6.c: New test.
	* gcc.target/loongarch/stack-check-prologue-7.c: New test.
	* gcc.target/loongarch/stack-check-prologue.h: New test.