From 0ce42fe12b8e909f30bd57ab24e739d7d6218650 Mon Sep 17 00:00:00 2001 From: Andrew Waterman Date: Tue, 23 Jan 2018 23:06:48 +0000 Subject: [PATCH] RISC-V: Add -mpreferred-stack-boundary option. 2018-01-23 Andrew Waterman gcc/ * config/riscv/riscv.c (riscv_stack_boundary): New. (riscv_option_override): Set riscv_stack_boundary. Handle riscv_preferred_stack_boundary_arg. * config/riscv/riscv.h (MIN_STACK_BOUNDARY, ABI_STACK_BOUNDARY): New. (BIGGEST_ALIGNMENT): Set to STACK_BOUNDARY. (STACK_BOUNDARY): Set to riscv_stack_boundary. (RISCV_STACK_ALIGN): Use STACK_BOUNDARY. * config/riscv/riscv.opt (mpreferred-stack-boundary): New. * doc/invoke.tex (RISC-V Options): Add -mpreferred-stack-boundary. Co-Authored-By: Jim Wilson From-SVN: r257005 --- gcc/ChangeLog | 13 +++++++++++++ gcc/config/riscv/riscv.c | 17 +++++++++++++++++ gcc/config/riscv/riscv.h | 17 ++++++++++++----- gcc/config/riscv/riscv.opt | 4 ++++ gcc/doc/invoke.texi | 11 +++++++++++ 5 files changed, 57 insertions(+), 5 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 04de55440f5..899b13e32f8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,16 @@ +2018-01-23 Andrew Waterman + Jim Wilson + + * config/riscv/riscv.c (riscv_stack_boundary): New. + (riscv_option_override): Set riscv_stack_boundary. Handle + riscv_preferred_stack_boundary_arg. + * config/riscv/riscv.h (MIN_STACK_BOUNDARY, ABI_STACK_BOUNDARY): New. + (BIGGEST_ALIGNMENT): Set to STACK_BOUNDARY. + (STACK_BOUNDARY): Set to riscv_stack_boundary. + (RISCV_STACK_ALIGN): Use STACK_BOUNDARY. + * config/riscv/riscv.opt (mpreferred-stack-boundary): New. + * doc/invoke.tex (RISC-V Options): Add -mpreferred-stack-boundary. + 2018-01-23 H.J. Lu PR target/83905 diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c index 20660a4061a..4ef7a1774c4 100644 --- a/gcc/config/riscv/riscv.c +++ b/gcc/config/riscv/riscv.c @@ -222,6 +222,9 @@ struct riscv_cpu_info { /* Whether unaligned accesses execute very slowly. */ bool riscv_slow_unaligned_access_p; +/* Stack alignment to assume/maintain. */ +unsigned riscv_stack_boundary; + /* Which tuning parameters to use. */ static const struct riscv_tune_info *tune_info; @@ -4111,6 +4114,20 @@ riscv_option_override (void) /* We do not yet support ILP32 on RV64. */ if (BITS_PER_WORD != POINTER_SIZE) error ("ABI requires -march=rv%d", POINTER_SIZE); + + /* Validate -mpreferred-stack-boundary= value. */ + riscv_stack_boundary = ABI_STACK_BOUNDARY; + if (riscv_preferred_stack_boundary_arg) + { + int min = ctz_hwi (MIN_STACK_BOUNDARY / 8); + int max = 8; + + if (!IN_RANGE (riscv_preferred_stack_boundary_arg, min, max)) + error ("-mpreferred-stack-boundary=%d must be between %d and %d", + riscv_preferred_stack_boundary_arg, min, max); + + riscv_stack_boundary = 8 << riscv_preferred_stack_boundary_arg; + } } /* Implement TARGET_CONDITIONAL_REGISTER_USAGE. */ diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h index cd37761b629..a002bff4480 100644 --- a/gcc/config/riscv/riscv.h +++ b/gcc/config/riscv/riscv.h @@ -123,8 +123,14 @@ along with GCC; see the file COPYING3. If not see /* Allocation boundary (in *bits*) for the code of a function. */ #define FUNCTION_BOUNDARY (TARGET_RVC ? 16 : 32) +/* The smallest supported stack boundary the calling convention supports. */ +#define MIN_STACK_BOUNDARY (2 * BITS_PER_WORD) + +/* The ABI stack alignment. */ +#define ABI_STACK_BOUNDARY 128 + /* There is no point aligning anything to a rounder boundary than this. */ -#define BIGGEST_ALIGNMENT 128 +#define BIGGEST_ALIGNMENT STACK_BOUNDARY /* The user-level ISA permits unaligned accesses, but they are not required of the privileged architecture. */ @@ -472,8 +478,8 @@ enum reg_class `crtl->outgoing_args_size'. */ #define OUTGOING_REG_PARM_STACK_SPACE(FNTYPE) 1 -#define STACK_BOUNDARY 128 - +#define STACK_BOUNDARY riscv_stack_boundary + /* Symbolic macros for the registers used to return integer and floating point values. */ @@ -528,8 +534,9 @@ typedef struct { #define EPILOGUE_USES(REGNO) ((REGNO) == RETURN_ADDR_REGNUM) -/* ABI requires 16-byte alignment, even on RV32. */ -#define RISCV_STACK_ALIGN(LOC) (((LOC) + 15) & -16) +/* Align based on stack boundary, which might have been set by the user. */ +#define RISCV_STACK_ALIGN(LOC) \ + (((LOC) + ((STACK_BOUNDARY/8)-1)) & -(STACK_BOUNDARY/8)) /* EXIT_IGNORE_STACK should be nonzero if, when returning from a function, the stack pointer does not matter. The value is tested only in diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt index 50df851afdf..581a26bb5c1 100644 --- a/gcc/config/riscv/riscv.opt +++ b/gcc/config/riscv/riscv.opt @@ -33,6 +33,10 @@ mabi= Target Report RejectNegative Joined Enum(abi_type) Var(riscv_abi) Init(ABI_ILP32) Specify integer and floating-point calling convention. +mpreferred-stack-boundary= +Target RejectNegative Joined UInteger Var(riscv_preferred_stack_boundary_arg) +Attempt to keep stack aligned to this power of 2. + Enum Name(abi_type) Type(enum riscv_abi_type) Supported ABIs (for use with the -mabi= option): diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 891de733160..f066349c2ff 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -992,6 +992,7 @@ See RS/6000 and PowerPC Options. -mdiv -mno-div @gol -march=@var{ISA-string} @gol -mtune=@var{processor-string} @gol +-mpreferred-stack-boundary=@var{num} @gol -msmall-data-limit=@var{N-bytes} @gol -msave-restore -mno-save-restore @gol -mstrict-align -mno-strict-align @gol @@ -22072,6 +22073,16 @@ lower-case. Examples include @samp{rv64i}, @samp{rv32g}, and @samp{rv32imaf}. Optimize the output for the given processor, specified by microarchitecture name. +@item -mpreferred-stack-boundary=@var{num} +@opindex mpreferred-stack-boundary +Attempt to keep the stack boundary aligned to a 2 raised to @var{num} +byte boundary. If @option{-mpreferred-stack-boundary} is not specified, +the default is 4 (16 bytes or 128-bits). + +@strong{Warning:} If you use this switch, then you must build all modules with +the same value, including any libraries. This includes the system libraries +and startup modules. + @item -msmall-data-limit=@var{n} @opindex msmall-data-limit Put global and static data smaller than @var{n} bytes into a special section -- 2.30.2