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tidy target HANDLE_ALIGN

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avr, kvx, metag, mn10300, nds32, v850, visium, and wasm32 targets
defined HANDLE_ALIGN without defining MAX_MEM_FOR_RS_ALIGN_CODE.  This
can result in a rather large chunk of memory being allocated.  Fix
that by a combination of changing the default allocation to one byte
and/or defining a target MAX_MEM_FOR_RS_ALIGN_CODE.

arm wanted to write out the entire set of nops, and limited allowed
code alignment to 64 bytes to prevent large memory allocations.
Fix that by making use of the fact that rs_align_code frags repeat
fr_var bytes at fr_literal + fr_fix to fill out the required area.
Fix metag, nds32 and kvx too, which it seems copied either arm or x86
in similarly not making use of repeating patterns.

It's worth mentioning that my tidy to kvx changed the order of nop
bundles, placing a short bundle first rather than last.

epiphany was totally broken in that uninitialised data was written out
for any alignment requiring more than three bytes of fill.

ppc created a new frag to handle a branch over a large number of nops.
This saves 4 bytes per rs_align_code frag, and most times the branch
isn't used so it is generally a win for memory usage, but I figured
the extra code complexity wasn't worth it.  So that code of mine goes.
visium copied the same scheme, so that goes too.

This leaves x86 as the only target making large allocations for
alignment frags.

	* frags.c (MAX_MEM_FOR_RS_ALIGN_CODE): Default to 1.
	* config/tc-aarch64.c (aarch64_handle_align): Remove always true
	condition.
	* config/tc-aarch64.h (MAX_MEM_FOR_RS_ALIGN_CODE): Move to be
	adjacent to HANDLE_ALIGN define.
	* config/tc-arm.c (arm_handle_align): Allow alignment of more
	than MAX_MEM_FOR_RS_ALIGN_CODE bytes.  Just write one repeat
	of nop pattern to frag.
	(arm_frag_align_code): Delete function.
	* config/tc-arm.h (MAX_MEM_ALIGNMENT_BYTES): Don't define.
	(MAX_MEM_FOR_RS_ALIGN_CODE): Set to 7.
	(md_do_align): Don't define.
	(arm_frag_align_code): Don't declare.
	* config/tc-epiphany.c (epiphany_handle_align): Correct frag
	so that nop_pattern repeats rather than random data.
	* config/tc-epiphany.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
	* config/tc-kvx.c (kvx_make_nops): Merge into..
	(kvx_handle_align): ..here.  Put short nop bundle first,
	followed by repeated full nop bundle.
	* config/tc-kvx.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
	* config/tc-m32c.h (HANDLE_ALIGN, MAX_MEM_FOR_RS_ALIGN_CODE):
	Don't define.
	* config/tc-metag.c (metag_handle_align): Just write one
	repeat of nop pattern to frag.
	* config/tc-metag.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
	* config/tc-nds32.c (nds32_handle_align): Just write one
	repeat of nop pattern to frag.
	* config/tc-nds32.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
	* config/tc-ppc.c (ppc_handle_align): Don't make a new frag
	for branch.
	* config/tc-ppc.h (MAX_MEM_FOR_RS_ALIGN_CODE): Increase to 8.
	* config/tc-visium.c (visium_handle_align): Don't make a new
	frag for branch.
	* config/tc-visium.h (MAX_MEM_FOR_RS_ALIGN_CODE): Define.
	* config/tc-wasm32.h (HANDLE_ALIGN): Don't define.
	* testsuite/gas/epiphany/nop.d,
	* testsuite/gas/epiphany/nop.s: New test.
	* testsuite/gas/epiphany/allinsn.exp: Run it.
	* testsuite/gas/kvx/nop-align.d: Adjust.
This commit is contained in:
Alan Modra
2025-05-17 15:11:14 +09:30
parent ebed2c2c43
commit 7ca6020a4e
23 changed files with 106 additions and 202 deletions
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13
gas/frags.c
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@@ -355,18 +355,11 @@ frag_align_pattern (int alignment, const char *fill_pattern,
#define NOP_OPCODE 0x00
#endif
/* Use this to restrict the amount of memory allocated for representing
the alignment code. Needs to be large enough to hold any fixed sized
/* Use this to specify the amount of memory allocated for representing
the alignment code. Needs to be large enough to hold any fixed size
prologue plus the replicating portion. */
#ifndef MAX_MEM_FOR_RS_ALIGN_CODE
/* Assume that if HANDLE_ALIGN is not defined then no special action
is required to code fill, which means that we get just repeat the
one NOP_OPCODE byte. */
# ifndef HANDLE_ALIGN
# define MAX_MEM_FOR_RS_ALIGN_CODE 1
# else
# define MAX_MEM_FOR_RS_ALIGN_CODE (((size_t) 1 << alignment) - 1)
# endif
# define MAX_MEM_FOR_RS_ALIGN_CODE 1
#endif
void