[net-next-2.6.git] / scripts / recordmcount.h

/*
 * recordmcount.h
 *
 * This code was taken out of recordmcount.c written by
 * Copyright 2009 John F. Reiser <jreiser@BitWagon.com>.  All rights reserved.
 *
 * The original code had the same algorithms for both 32bit
 * and 64bit ELF files, but the code was duplicated to support
 * the difference in structures that were used. This
 * file creates a macro of everything that is different between
 * the 64 and 32 bit code, such that by including this header
 * twice we can create both sets of functions by including this
 * header once with RECORD_MCOUNT_64 undefined, and again with
 * it defined.
 *
 * This conversion to macros was done by:
 * Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
 *
 * Licensed under the GNU General Public License, version 2 (GPLv2).
 */
#undef append_func
#undef sift_rel_mcount
#undef find_secsym_ndx
#undef __has_rel_mcount
#undef has_rel_mcount
#undef tot_relsize
#undef do_func
#undef Elf_Ehdr
#undef Elf_Shdr
#undef Elf_Rel
#undef Elf_Rela
#undef Elf_Sym
#undef ELF_R_SYM
#undef ELF_R_INFO
#undef ELF_ST_BIND
#undef uint_t
#undef _w
#undef _align
#undef _size

#ifdef RECORD_MCOUNT_64
# define append_func		append64
# define sift_rel_mcount	sift64_rel_mcount
# define find_secsym_ndx	find64_secsym_ndx
# define __has_rel_mcount	__has64_rel_mcount
# define has_rel_mcount		has64_rel_mcount
# define tot_relsize		tot64_relsize
# define do_func		do64
# define Elf_Ehdr		Elf64_Ehdr
# define Elf_Shdr		Elf64_Shdr
# define Elf_Rel		Elf64_Rel
# define Elf_Rela		Elf64_Rela
# define Elf_Sym		Elf64_Sym
# define ELF_R_SYM		ELF64_R_SYM
# define ELF_R_INFO		ELF64_R_INFO
# define ELF_ST_BIND		ELF64_ST_BIND
# define uint_t			uint64_t
# define _w			w8
# define _align			7u
# define _size			8
#else
# define append_func		append32
# define sift_rel_mcount	sift32_rel_mcount
# define find_secsym_ndx	find32_secsym_ndx
# define __has_rel_mcount	__has32_rel_mcount
# define has_rel_mcount		has32_rel_mcount
# define tot_relsize		tot32_relsize
# define do_func		do32
# define Elf_Ehdr		Elf32_Ehdr
# define Elf_Shdr		Elf32_Shdr
# define Elf_Rel		Elf32_Rel
# define Elf_Rela		Elf32_Rela
# define Elf_Sym		Elf32_Sym
# define ELF_R_SYM		ELF32_R_SYM
# define ELF_R_INFO		ELF32_R_INFO
# define ELF_ST_BIND		ELF32_ST_BIND
# define uint_t			uint32_t
# define _w			w
# define _align			3u
# define _size			4
#endif

/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
static void append_func(Elf_Ehdr *const ehdr,
			Elf_Shdr *const shstr,
			uint_t const *const mloc0,
			uint_t const *const mlocp,
			Elf_Rel const *const mrel0,
			Elf_Rel const *const mrelp,
			unsigned int const rel_entsize,
			unsigned int const symsec_sh_link)
{
	/* Begin constructing output file */
	Elf_Shdr mcsec;
	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
		? ".rela__mcount_loc"
		:  ".rel__mcount_loc";
	unsigned const old_shnum = w2(ehdr->e_shnum);
	uint_t const old_shoff = _w(ehdr->e_shoff);
	uint_t const old_shstr_sh_size   = _w(shstr->sh_size);
	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
	uint_t new_e_shoff;

	shstr->sh_size = _w(t);
	shstr->sh_offset = _w(sb.st_size);
	t += sb.st_size;
	t += (_align & -t);  /* word-byte align */
	new_e_shoff = t;

	/* body for new shstrtab */
	ulseek(fd_map, sb.st_size, SEEK_SET);
	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
	uwrite(fd_map, mc_name, 1 + strlen(mc_name));

	/* old(modified) Elf_Shdr table, word-byte aligned */
	ulseek(fd_map, t, SEEK_SET);
	t += sizeof(Elf_Shdr) * old_shnum;
	uwrite(fd_map, old_shoff + (void *)ehdr,
	       sizeof(Elf_Shdr) * old_shnum);

	/* new sections __mcount_loc and .rel__mcount_loc */
	t += 2*sizeof(mcsec);
	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
		+ old_shstr_sh_size);
	mcsec.sh_type = w(SHT_PROGBITS);
	mcsec.sh_flags = _w(SHF_ALLOC);
	mcsec.sh_addr = 0;
	mcsec.sh_offset = _w(t);
	mcsec.sh_size = _w((void *)mlocp - (void *)mloc0);
	mcsec.sh_link = 0;
	mcsec.sh_info = 0;
	mcsec.sh_addralign = _w(_size);
	mcsec.sh_entsize = _w(_size);
	uwrite(fd_map, &mcsec, sizeof(mcsec));

	mcsec.sh_name = w(old_shstr_sh_size);
	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
		? w(SHT_RELA)
		: w(SHT_REL);
	mcsec.sh_flags = 0;
	mcsec.sh_addr = 0;
	mcsec.sh_offset = _w((void *)mlocp - (void *)mloc0 + t);
	mcsec.sh_size   = _w((void *)mrelp - (void *)mrel0);
	mcsec.sh_link = w(symsec_sh_link);
	mcsec.sh_info = w(old_shnum);
	mcsec.sh_addralign = _w(_size);
	mcsec.sh_entsize = _w(rel_entsize);
	uwrite(fd_map, &mcsec, sizeof(mcsec));

	uwrite(fd_map, mloc0, (void *)mlocp - (void *)mloc0);
	uwrite(fd_map, mrel0, (void *)mrelp - (void *)mrel0);

	ehdr->e_shoff = _w(new_e_shoff);
	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum));  /* {.rel,}__mcount_loc */
	ulseek(fd_map, 0, SEEK_SET);
	uwrite(fd_map, ehdr, sizeof(*ehdr));
}


/*
 * Look at the relocations in order to find the calls to mcount.
 * Accumulate the section offsets that are found, and their relocation info,
 * onto the end of the existing arrays.
 */
static uint_t *sift_rel_mcount(uint_t *mlocp,
			       unsigned const offbase,
			       Elf_Rel **const mrelpp,
			       Elf_Shdr const *const relhdr,
			       Elf_Ehdr const *const ehdr,
			       unsigned const recsym,
			       uint_t const recval,
			       unsigned const reltype)
{
	uint_t *const mloc0 = mlocp;
	Elf_Rel *mrelp = *mrelpp;
	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
		+ (void *)ehdr);
	unsigned const symsec_sh_link = w(relhdr->sh_link);
	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
		+ (void *)ehdr);

	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
	char const *const str0 = (char const *)(_w(strsec->sh_offset)
		+ (void *)ehdr);

	Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
		+ (void *)ehdr);
	unsigned rel_entsize = _w(relhdr->sh_entsize);
	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
	Elf_Rel const *relp = rel0;

	unsigned mcountsym = 0;
	unsigned t;

	for (t = nrel; t; --t) {
		if (!mcountsym) {
			Elf_Sym const *const symp =
				&sym0[ELF_R_SYM(_w(relp->r_info))];
			char const *symname = &str0[w(symp->st_name)];

			if ('.' == symname[0])
				++symname;  /* ppc64 hack */
			if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
					symname))
				mcountsym = ELF_R_SYM(_w(relp->r_info));
		}

		if (mcountsym == ELF_R_SYM(_w(relp->r_info))) {
			uint_t const addend = _w(_w(relp->r_offset) - recval);

			mrelp->r_offset = _w(offbase
				+ ((void *)mlocp - (void *)mloc0));
			mrelp->r_info = _w(ELF_R_INFO(recsym, reltype));
			if (sizeof(Elf_Rela) == rel_entsize) {
				((Elf_Rela *)mrelp)->r_addend = addend;
				*mlocp++ = 0;
			} else
				*mlocp++ = addend;

			mrelp = (Elf_Rel *)(rel_entsize + (void *)mrelp);
		}
		relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
	}
	*mrelpp = mrelp;
	return mlocp;
}


/*
 * Find a symbol in the given section, to be used as the base for relocating
 * the table of offsets of calls to mcount.  A local or global symbol suffices,
 * but avoid a Weak symbol because it may be overridden; the change in value
 * would invalidate the relocations of the offsets of the calls to mcount.
 * Often the found symbol will be the unnamed local symbol generated by
 * GNU 'as' for the start of each section.  For example:
 *    Num:    Value  Size Type    Bind   Vis      Ndx Name
 *      2: 00000000     0 SECTION LOCAL  DEFAULT    1
 */
static unsigned find_secsym_ndx(unsigned const txtndx,
				char const *const txtname,
				uint_t *const recvalp,
				Elf_Shdr const *const symhdr,
				Elf_Ehdr const *const ehdr)
{
	Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symhdr->sh_offset)
		+ (void *)ehdr);
	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
	Elf_Sym const *symp;
	unsigned t;

	for (symp = sym0, t = nsym; t; --t, ++symp) {
		unsigned int const st_bind = ELF_ST_BIND(symp->st_info);

		if (txtndx == w2(symp->st_shndx)
			/* avoid STB_WEAK */
		    && (STB_LOCAL == st_bind || STB_GLOBAL == st_bind)) {
			*recvalp = _w(symp->st_value);
			return symp - sym0;
		}
	}
	fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
		txtndx, txtname);
	fail_file();
}


/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
static char const *
__has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
		 Elf_Shdr const *const shdr0,
		 char const *const shstrtab,
		 char const *const fname)
{
	/* .sh_info depends on .sh_type == SHT_REL[,A] */
	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
	char const *const txtname = &shstrtab[w(txthdr->sh_name)];

	if (0 == strcmp("__mcount_loc", txtname)) {
		fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
			fname);
		succeed_file();
	}
	if (SHT_PROGBITS != w(txthdr->sh_type) ||
	    !is_mcounted_section_name(txtname))
		return NULL;
	return txtname;
}

static char const *has_rel_mcount(Elf_Shdr const *const relhdr,
				  Elf_Shdr const *const shdr0,
				  char const *const shstrtab,
				  char const *const fname)
{
	if (SHT_REL  != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type))
		return NULL;
	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
}


static unsigned tot_relsize(Elf_Shdr const *const shdr0,
			    unsigned nhdr,
			    const char *const shstrtab,
			    const char *const fname)
{
	unsigned totrelsz = 0;
	Elf_Shdr const *shdrp = shdr0;

	for (; nhdr; --nhdr, ++shdrp) {
		if (has_rel_mcount(shdrp, shdr0, shstrtab, fname))
			totrelsz += _w(shdrp->sh_size);
	}
	return totrelsz;
}


/* Overall supervision for Elf32 ET_REL file. */
static void
do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
{
	Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
		+ (void *)ehdr);
	unsigned const nhdr = w2(ehdr->e_shnum);
	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
	char const *const shstrtab = (char const *)(_w(shstr->sh_offset)
		+ (void *)ehdr);

	Elf_Shdr const *relhdr;
	unsigned k;

	/* Upper bound on space: assume all relevant relocs are for mcount. */
	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
	Elf_Rel *const mrel0 = umalloc(totrelsz);
	Elf_Rel *      mrelp = mrel0;

	/* 2*sizeof(address) <= sizeof(Elf_Rel) */
	uint_t *const mloc0 = umalloc(totrelsz>>1);
	uint_t *      mlocp = mloc0;

	unsigned rel_entsize = 0;
	unsigned symsec_sh_link = 0;

	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
		char const *const txtname = has_rel_mcount(relhdr, shdr0,
			shstrtab, fname);
		if (txtname) {
			uint_t recval = 0;
			unsigned const recsym = find_secsym_ndx(
				w(relhdr->sh_info), txtname, &recval,
				&shdr0[symsec_sh_link = w(relhdr->sh_link)],
				ehdr);

			rel_entsize = _w(relhdr->sh_entsize);
			mlocp = sift_rel_mcount(mlocp,
				(void *)mlocp - (void *)mloc0, &mrelp,
				relhdr, ehdr, recsym, recval, reltype);
		}
	}
	if (mloc0 != mlocp) {
		append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
			    rel_entsize, symsec_sh_link);
	}
	free(mrel0);
	free(mloc0);
}
Commit	Line	Data
c28d5077 SR	1	/*
	2	* recordmcount.h
	3	*
	4	* This code was taken out of recordmcount.c written by
	5	* Copyright 2009 John F. Reiser <jreiser@BitWagon.com>. All rights reserved.
	6	*
	7	* The original code had the same algorithms for both 32bit
	8	* and 64bit ELF files, but the code was duplicated to support
	9	* the difference in structures that were used. This
	10	* file creates a macro of everything that is different between
	11	* the 64 and 32 bit code, such that by including this header
	12	* twice we can create both sets of functions by including this
	13	* header once with RECORD_MCOUNT_64 undefined, and again with
	14	* it defined.
	15	*
	16	* This conversion to macros was done by:
	17	* Copyright 2010 Steven Rostedt <srostedt@redhat.com>, Red Hat Inc.
	18	*
	19	* Licensed under the GNU General Public License, version 2 (GPLv2).
	20	*/
	21	#undef append_func
	22	#undef sift_rel_mcount
	23	#undef find_secsym_ndx
	24	#undef __has_rel_mcount
	25	#undef has_rel_mcount
	26	#undef tot_relsize
	27	#undef do_func
	28	#undef Elf_Ehdr
	29	#undef Elf_Shdr
	30	#undef Elf_Rel
	31	#undef Elf_Rela
	32	#undef Elf_Sym
	33	#undef ELF_R_SYM
	34	#undef ELF_R_INFO
	35	#undef ELF_ST_BIND
	36	#undef uint_t
	37	#undef _w
	38	#undef _align
	39	#undef _size
	40
	41	#ifdef RECORD_MCOUNT_64
	42	# define append_func append64
	43	# define sift_rel_mcount sift64_rel_mcount
	44	# define find_secsym_ndx find64_secsym_ndx
	45	# define __has_rel_mcount __has64_rel_mcount
	46	# define has_rel_mcount has64_rel_mcount
	47	# define tot_relsize tot64_relsize
	48	# define do_func do64
	49	# define Elf_Ehdr Elf64_Ehdr
	50	# define Elf_Shdr Elf64_Shdr
	51	# define Elf_Rel Elf64_Rel
	52	# define Elf_Rela Elf64_Rela
	53	# define Elf_Sym Elf64_Sym
	54	# define ELF_R_SYM ELF64_R_SYM
	55	# define ELF_R_INFO ELF64_R_INFO
	56	# define ELF_ST_BIND ELF64_ST_BIND
	57	# define uint_t uint64_t
	58	# define _w w8
	59	# define _align 7u
	60	# define _size 8
	61	#else
	62	# define append_func append32
	63	# define sift_rel_mcount sift32_rel_mcount
	64	# define find_secsym_ndx find32_secsym_ndx
65	# define __has_rel_mcount __has32_rel_mcount
66	# define has_rel_mcount has32_rel_mcount
67	# define tot_relsize tot32_relsize
68	# define do_func do32
69	# define Elf_Ehdr Elf32_Ehdr
70	# define Elf_Shdr Elf32_Shdr
71	# define Elf_Rel Elf32_Rel
72	# define Elf_Rela Elf32_Rela
73	# define Elf_Sym Elf32_Sym
74	# define ELF_R_SYM ELF32_R_SYM
75	# define ELF_R_INFO ELF32_R_INFO
76	# define ELF_ST_BIND ELF32_ST_BIND
77	# define uint_t uint32_t
78	# define _w w
79	# define _align 3u
80	# define _size 4
81	#endif
82
83	/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
84	static void append_func(Elf_Ehdr *const ehdr,
85	Elf_Shdr *const shstr,
86	uint_t const *const mloc0,
87	uint_t const *const mlocp,
88	Elf_Rel const *const mrel0,
89	Elf_Rel const *const mrelp,
90	unsigned int const rel_entsize,
91	unsigned int const symsec_sh_link)
92	{
93	/* Begin constructing output file */
94	Elf_Shdr mcsec;
95	char const *mc_name = (sizeof(Elf_Rela) == rel_entsize)
96	? ".rela__mcount_loc"
97	: ".rel__mcount_loc";
98	unsigned const old_shnum = w2(ehdr->e_shnum);
99	uint_t const old_shoff = _w(ehdr->e_shoff);
100	uint_t const old_shstr_sh_size = _w(shstr->sh_size);
101	uint_t const old_shstr_sh_offset = _w(shstr->sh_offset);
102	uint_t t = 1 + strlen(mc_name) + _w(shstr->sh_size);
103	uint_t new_e_shoff;
104
105	shstr->sh_size = _w(t);
106	shstr->sh_offset = _w(sb.st_size);
107	t += sb.st_size;
108	t += (_align & -t); /* word-byte align */
109	new_e_shoff = t;
110
111	/* body for new shstrtab */
112	ulseek(fd_map, sb.st_size, SEEK_SET);
113	uwrite(fd_map, old_shstr_sh_offset + (void *)ehdr, old_shstr_sh_size);
114	uwrite(fd_map, mc_name, 1 + strlen(mc_name));
115
116	/* old(modified) Elf_Shdr table, word-byte aligned */
117	ulseek(fd_map, t, SEEK_SET);
118	t += sizeof(Elf_Shdr) * old_shnum;
119	uwrite(fd_map, old_shoff + (void *)ehdr,
120	sizeof(Elf_Shdr) * old_shnum);
121
122	/* new sections __mcount_loc and .rel__mcount_loc */
123	t += 2*sizeof(mcsec);
124	mcsec.sh_name = w((sizeof(Elf_Rela) == rel_entsize) + strlen(".rel")
125	+ old_shstr_sh_size);
126	mcsec.sh_type = w(SHT_PROGBITS);
127	mcsec.sh_flags = _w(SHF_ALLOC);
128	mcsec.sh_addr = 0;
129	mcsec.sh_offset = _w(t);
130	mcsec.sh_size = _w((void )mlocp - (void )mloc0);
131	mcsec.sh_link = 0;
132	mcsec.sh_info = 0;
133	mcsec.sh_addralign = _w(_size);
134	mcsec.sh_entsize = _w(_size);
135	uwrite(fd_map, &mcsec, sizeof(mcsec));
136
137	mcsec.sh_name = w(old_shstr_sh_size);
138	mcsec.sh_type = (sizeof(Elf_Rela) == rel_entsize)
139	? w(SHT_RELA)
140	: w(SHT_REL);
141	mcsec.sh_flags = 0;
142	mcsec.sh_addr = 0;
143	mcsec.sh_offset = _w((void )mlocp - (void )mloc0 + t);
144	mcsec.sh_size = _w((void )mrelp - (void )mrel0);
145	mcsec.sh_link = w(symsec_sh_link);
146	mcsec.sh_info = w(old_shnum);
147	mcsec.sh_addralign = _w(_size);
148	mcsec.sh_entsize = _w(rel_entsize);
149	uwrite(fd_map, &mcsec, sizeof(mcsec));
150
151	uwrite(fd_map, mloc0, (void )mlocp - (void )mloc0);
152	uwrite(fd_map, mrel0, (void )mrelp - (void )mrel0);
153
154	ehdr->e_shoff = _w(new_e_shoff);
155	ehdr->e_shnum = w2(2 + w2(ehdr->e_shnum)); /* {.rel,}__mcount_loc */
156	ulseek(fd_map, 0, SEEK_SET);
157	uwrite(fd_map, ehdr, sizeof(*ehdr));
158	}
159
160
161	/*
162	* Look at the relocations in order to find the calls to mcount.
163	* Accumulate the section offsets that are found, and their relocation info,
164	* onto the end of the existing arrays.
165	*/
166	static uint_t sift_rel_mcount(uint_t mlocp,
167	unsigned const offbase,
168	Elf_Rel **const mrelpp,
169	Elf_Shdr const *const relhdr,
170	Elf_Ehdr const *const ehdr,
171	unsigned const recsym,
172	uint_t const recval,
173	unsigned const reltype)
174	{
175	uint_t *const mloc0 = mlocp;
176	Elf_Rel mrelp = mrelpp;
177	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
178	+ (void *)ehdr);
179	unsigned const symsec_sh_link = w(relhdr->sh_link);
180	Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
181	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symsec->sh_offset)
182	+ (void *)ehdr);
183
184	Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
185	char const const str0 = (char const )(_w(strsec->sh_offset)
186	+ (void *)ehdr);
187
188	Elf_Rel const const rel0 = (Elf_Rel const )(_w(relhdr->sh_offset)
189	+ (void *)ehdr);
190	unsigned rel_entsize = _w(relhdr->sh_entsize);
191	unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
192	Elf_Rel const *relp = rel0;
193
194	unsigned mcountsym = 0;
195	unsigned t;
196
197	for (t = nrel; t; --t) {
198	if (!mcountsym) {
199	Elf_Sym const *const symp =
200	&sym0[ELF_R_SYM(_w(relp->r_info))];
201	char const *symname = &str0[w(symp->st_name)];
202
203	if ('.' == symname[0])
204	++symname; /* ppc64 hack */
205	if (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
206	symname))
207	mcountsym = ELF_R_SYM(_w(relp->r_info));
208	}
209
210	if (mcountsym == ELF_R_SYM(_w(relp->r_info))) {
211	uint_t const addend = _w(_w(relp->r_offset) - recval);
212
213	mrelp->r_offset = _w(offbase
214	+ ((void )mlocp - (void )mloc0));
215	mrelp->r_info = _w(ELF_R_INFO(recsym, reltype));
216	if (sizeof(Elf_Rela) == rel_entsize) {
217	((Elf_Rela *)mrelp)->r_addend = addend;
218	*mlocp++ = 0;
219	} else
220	*mlocp++ = addend;
221
222	mrelp = (Elf_Rel )(rel_entsize + (void )mrelp);
223	}
224	relp = (Elf_Rel const )(rel_entsize + (void )relp);
225	}
226	*mrelpp = mrelp;
227	return mlocp;
228	}
229
230
231	/*
232	* Find a symbol in the given section, to be used as the base for relocating
233	* the table of offsets of calls to mcount. A local or global symbol suffices,
234	* but avoid a Weak symbol because it may be overridden; the change in value
235	* would invalidate the relocations of the offsets of the calls to mcount.
236	* Often the found symbol will be the unnamed local symbol generated by
237	* GNU 'as' for the start of each section. For example:
238	* Num: Value Size Type Bind Vis Ndx Name
239	* 2: 00000000 0 SECTION LOCAL DEFAULT 1
240	*/
241	static unsigned find_secsym_ndx(unsigned const txtndx,
242	char const *const txtname,
243	uint_t *const recvalp,
244	Elf_Shdr const *const symhdr,
245	Elf_Ehdr const *const ehdr)
246	{
247	Elf_Sym const const sym0 = (Elf_Sym const )(_w(symhdr->sh_offset)
248	+ (void *)ehdr);
249	unsigned const nsym = _w(symhdr->sh_size) / _w(symhdr->sh_entsize);
250	Elf_Sym const *symp;
251	unsigned t;
252
253	for (symp = sym0, t = nsym; t; --t, ++symp) {
254	unsigned int const st_bind = ELF_ST_BIND(symp->st_info);
255
256	if (txtndx == w2(symp->st_shndx)
257	/* avoid STB_WEAK */
258	&& (STB_LOCAL == st_bind \|\| STB_GLOBAL == st_bind)) {
259	*recvalp = _w(symp->st_value);
260	return symp - sym0;
261	}
262	}
263	fprintf(stderr, "Cannot find symbol for section %d: %s.\n",
264	txtndx, txtname);
265	fail_file();
266	}
267
268
269	/* Evade ISO C restriction: no declaration after statement in has_rel_mcount. */
270	static char const *
271	__has_rel_mcount(Elf_Shdr const const relhdr, / is SHT_REL or SHT_RELA */
272	Elf_Shdr const *const shdr0,
273	char const *const shstrtab,
274	char const *const fname)
275	{
276	/* .sh_info depends on .sh_type == SHT_REL[,A] */
277	Elf_Shdr const *const txthdr = &shdr0[w(relhdr->sh_info)];
278	char const *const txtname = &shstrtab[w(txthdr->sh_name)];
279
280	if (0 == strcmp("__mcount_loc", txtname)) {
281	fprintf(stderr, "warning: __mcount_loc already exists: %s\n",
282	fname);
283	succeed_file();
284	}
285	if (SHT_PROGBITS != w(txthdr->sh_type) \|\|
286	!is_mcounted_section_name(txtname))
287	return NULL;
288	return txtname;
289	}
290
291	static char const has_rel_mcount(Elf_Shdr const const relhdr,
292	Elf_Shdr const *const shdr0,
293	char const *const shstrtab,
294	char const *const fname)
295	{
296	if (SHT_REL != w(relhdr->sh_type) && SHT_RELA != w(relhdr->sh_type))
297	return NULL;
298	return __has_rel_mcount(relhdr, shdr0, shstrtab, fname);
299	}
300
301
302	static unsigned tot_relsize(Elf_Shdr const *const shdr0,
303	unsigned nhdr,
304	const char *const shstrtab,
305	const char *const fname)
306	{
307	unsigned totrelsz = 0;
308	Elf_Shdr const *shdrp = shdr0;
309
310	for (; nhdr; --nhdr, ++shdrp) {
311	if (has_rel_mcount(shdrp, shdr0, shstrtab, fname))
312	totrelsz += _w(shdrp->sh_size);
313	}
314	return totrelsz;
315	}
316
317
318	/* Overall supervision for Elf32 ET_REL file. */
319	static void
320	do_func(Elf_Ehdr const ehdr, char const const fname, unsigned const reltype)
321	{
322	Elf_Shdr const shdr0 = (Elf_Shdr )(_w(ehdr->e_shoff)
323	+ (void *)ehdr);
324	unsigned const nhdr = w2(ehdr->e_shnum);
325	Elf_Shdr *const shstr = &shdr0[w2(ehdr->e_shstrndx)];
326	char const const shstrtab = (char const )(_w(shstr->sh_offset)
327	+ (void *)ehdr);
328
329	Elf_Shdr const *relhdr;
330	unsigned k;
331
332	/* Upper bound on space: assume all relevant relocs are for mcount. */
333	unsigned const totrelsz = tot_relsize(shdr0, nhdr, shstrtab, fname);
334	Elf_Rel *const mrel0 = umalloc(totrelsz);
335	Elf_Rel * mrelp = mrel0;
336
337	/* 2sizeof(address) <= sizeof(Elf_Rel) /
338	uint_t *const mloc0 = umalloc(totrelsz>>1);
339	uint_t * mlocp = mloc0;
340
341	unsigned rel_entsize = 0;
342	unsigned symsec_sh_link = 0;
343
344	for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
345	char const *const txtname = has_rel_mcount(relhdr, shdr0,
346	shstrtab, fname);
347	if (txtname) {
348	uint_t recval = 0;
349	unsigned const recsym = find_secsym_ndx(
350	w(relhdr->sh_info), txtname, &recval,
351	&shdr0[symsec_sh_link = w(relhdr->sh_link)],
352	ehdr);
353
354	rel_entsize = _w(relhdr->sh_entsize);
355	mlocp = sift_rel_mcount(mlocp,
356	(void )mlocp - (void )mloc0, &mrelp,
357	relhdr, ehdr, recsym, recval, reltype);
358	}
359	}
360	if (mloc0 != mlocp) {
361	append_func(ehdr, shstr, mloc0, mlocp, mrel0, mrelp,
362	rel_entsize, symsec_sh_link);
363	}
364	free(mrel0);
365	free(mloc0);
366	}