Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 297 insertions, 0 deletions

diff --git a/REORG.TODO/elf/dl-hwcaps.c b/REORG.TODO/elf/dl-hwcaps.c
new file mode 100644
index 0000000000..ac50fd2c38
--- /dev/null
+++ b/REORG.TODO/elf/dl-hwcaps.c
@@ -0,0 +1,297 @@
+/* Hardware capability support for run-time dynamic loader.
+   Copyright (C) 2012-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <assert.h>
+#include <elf.h>
+#include <errno.h>
+#include <libintl.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+
+#include <dl-procinfo.h>
+#include <dl-hwcaps.h>
+
+#ifdef _DL_FIRST_PLATFORM
+# define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT)
+#else
+# define _DL_FIRST_EXTRA _DL_HWCAP_COUNT
+#endif
+
+/* Return an array of useful/necessary hardware capability names.  */
+const struct r_strlenpair *
+internal_function
+_dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz,
+		      size_t *max_capstrlen)
+{
+  uint64_t hwcap_mask = GET_HWCAP_MASK();
+  /* Determine how many important bits are set.  */
+  uint64_t masked = GLRO(dl_hwcap) & hwcap_mask;
+  size_t cnt = platform != NULL;
+  size_t n, m;
+  size_t total;
+  struct r_strlenpair *result;
+  struct r_strlenpair *rp;
+  char *cp;
+
+  /* Count the number of bits set in the masked value.  */
+  for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n)
+    if ((masked & (1ULL << n)) != 0)
+      ++cnt;
+
+#ifdef NEED_DL_SYSINFO_DSO
+  /* The system-supplied DSO can contain a note of type 2, vendor "GNU".
+     This gives us a list of names to treat as fake hwcap bits.  */
+
+  const char *dsocaps = NULL;
+  size_t dsocapslen = 0;
+  if (GLRO(dl_sysinfo_map) != NULL)
+    {
+      const ElfW(Phdr) *const phdr = GLRO(dl_sysinfo_map)->l_phdr;
+      const ElfW(Word) phnum = GLRO(dl_sysinfo_map)->l_phnum;
+      for (uint_fast16_t i = 0; i < phnum; ++i)
+	if (phdr[i].p_type == PT_NOTE)
+	  {
+	    const ElfW(Addr) start = (phdr[i].p_vaddr
+				      + GLRO(dl_sysinfo_map)->l_addr);
+	    /* The standard ELF note layout is exactly as the anonymous struct.
+	       The next element is a variable length vendor name of length
+	       VENDORLEN (with a real length rounded to ElfW(Word)), followed
+	       by the data of length DATALEN (with a real length rounded to
+	       ElfW(Word)).  */
+	    const struct
+	    {
+	      ElfW(Word) vendorlen;
+	      ElfW(Word) datalen;
+	      ElfW(Word) type;
+	    } *note = (const void *) start;
+	    while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz)
+	      {
+#define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word)))
+		/* The layout of the type 2, vendor "GNU" note is as follows:
+		   .long <Number of capabilities enabled by this note>
+		   .long <Capabilities mask> (as mask >> _DL_FIRST_EXTRA).
+		   .byte <The bit number for the next capability>
+		   .asciz <The name of the capability>.  */
+		if (note->type == NT_GNU_HWCAP
+		    && note->vendorlen == sizeof "GNU"
+		    && !memcmp ((note + 1), "GNU", sizeof "GNU")
+		    && note->datalen > 2 * sizeof (ElfW(Word)) + 2)
+		  {
+		    const ElfW(Word) *p = ((const void *) (note + 1)
+					   + ROUND (sizeof "GNU"));
+		    cnt += *p++;
+		    ++p;	/* Skip mask word.  */
+		    dsocaps = (const char *) p; /* Pseudo-string "<b>name"  */
+		    dsocapslen = note->datalen - sizeof *p * 2;
+		    break;
+		  }
+		note = ((const void *) (note + 1)
+			+ ROUND (note->vendorlen) + ROUND (note->datalen));
+#undef ROUND
+	      }
+	    if (dsocaps != NULL)
+	      break;
+	  }
+    }
+#endif
+
+  /* For TLS enabled builds always add 'tls'.  */
+  ++cnt;
+
+  /* Create temporary data structure to generate result table.  */
+  struct r_strlenpair temp[cnt];
+  m = 0;
+#ifdef NEED_DL_SYSINFO_DSO
+  if (dsocaps != NULL)
+    {
+      /* dsocaps points to the .asciz string, and -1 points to the mask
+         .long just before the string.  */
+      const ElfW(Word) mask = ((const ElfW(Word) *) dsocaps)[-1];
+      GLRO(dl_hwcap) |= (uint64_t) mask << _DL_FIRST_EXTRA;
+      /* Note that we add the dsocaps to the set already chosen by the
+	 LD_HWCAP_MASK environment variable (or default HWCAP_IMPORTANT).
+	 So there is no way to request ignoring an OS-supplied dsocap
+	 string and bit like you can ignore an OS-supplied HWCAP bit.  */
+      hwcap_mask |= (uint64_t) mask << _DL_FIRST_EXTRA;
+#if HAVE_TUNABLES
+      TUNABLE_SET (glibc, tune, hwcap_mask, uint64_t, hwcap_mask);
+#else
+      GLRO(dl_hwcap_mask) = hwcap_mask;
+#endif
+      size_t len;
+      for (const char *p = dsocaps; p < dsocaps + dsocapslen; p += len + 1)
+	{
+	  uint_fast8_t bit = *p++;
+	  len = strlen (p);
+
+	  /* Skip entries that are not enabled in the mask word.  */
+	  if (__glibc_likely (mask & ((ElfW(Word)) 1 << bit)))
+	    {
+	      temp[m].str = p;
+	      temp[m].len = len;
+	      ++m;
+	    }
+	  else
+	    --cnt;
+	}
+    }
+#endif
+  for (n = 0; masked != 0; ++n)
+    if ((masked & (1ULL << n)) != 0)
+      {
+	temp[m].str = _dl_hwcap_string (n);
+	temp[m].len = strlen (temp[m].str);
+	masked ^= 1ULL << n;
+	++m;
+      }
+  if (platform != NULL)
+    {
+      temp[m].str = platform;
+      temp[m].len = platform_len;
+      ++m;
+    }
+
+  temp[m].str = "tls";
+  temp[m].len = 3;
+  ++m;
+
+  assert (m == cnt);
+
+  /* Determine the total size of all strings together.  */
+  if (cnt == 1)
+    total = temp[0].len + 1;
+  else
+    {
+      total = temp[0].len + temp[cnt - 1].len + 2;
+      if (cnt > 2)
+	{
+	  total <<= 1;
+	  for (n = 1; n + 1 < cnt; ++n)
+	    total += temp[n].len + 1;
+	  if (cnt > 3
+	      && (cnt >= sizeof (size_t) * 8
+		  || total + (sizeof (*result) << 3)
+		     >= (1UL << (sizeof (size_t) * 8 - cnt + 3))))
+	    _dl_signal_error (ENOMEM, NULL, NULL,
+			      N_("cannot create capability list"));
+
+	  total <<= cnt - 3;
+	}
+    }
+
+  /* The result structure: we use a very compressed way to store the
+     various combinations of capability names.  */
+  *sz = 1 << cnt;
+  result = (struct r_strlenpair *) malloc (*sz * sizeof (*result) + total);
+  if (result == NULL)
+    _dl_signal_error (ENOMEM, NULL, NULL,
+		      N_("cannot create capability list"));
+
+  if (cnt == 1)
+    {
+      result[0].str = (char *) (result + *sz);
+      result[0].len = temp[0].len + 1;
+      result[1].str = (char *) (result + *sz);
+      result[1].len = 0;
+      cp = __mempcpy ((char *) (result + *sz), temp[0].str, temp[0].len);
+      *cp = '/';
+      *sz = 2;
+      *max_capstrlen = result[0].len;
+
+      return result;
+    }
+
+  /* Fill in the information.  This follows the following scheme
+     (indices from TEMP for four strings):
+	entry #0: 0, 1, 2, 3	binary: 1111
+	      #1: 0, 1, 3		1101
+	      #2: 0, 2, 3		1011
+	      #3: 0, 3			1001
+     This allows the representation of all possible combinations of
+     capability names in the string.  First generate the strings.  */
+  result[1].str = result[0].str = cp = (char *) (result + *sz);
+#define add(idx) \
+      cp = __mempcpy (__mempcpy (cp, temp[idx].str, temp[idx].len), "/", 1);
+  if (cnt == 2)
+    {
+      add (1);
+      add (0);
+    }
+  else
+    {
+      n = 1 << (cnt - 1);
+      do
+	{
+	  n -= 2;
+
+	  /* We always add the last string.  */
+	  add (cnt - 1);
+
+	  /* Add the strings which have the bit set in N.  */
+	  for (m = cnt - 2; m > 0; --m)
+	    if ((n & (1 << m)) != 0)
+	      add (m);
+
+	  /* Always add the first string.  */
+	  add (0);
+	}
+      while (n != 0);
+    }
+#undef add
+
+  /* Now we are ready to install the string pointers and length.  */
+  for (n = 0; n < (1UL << cnt); ++n)
+    result[n].len = 0;
+  n = cnt;
+  do
+    {
+      size_t mask = 1 << --n;
+
+      rp = result;
+      for (m = 1 << cnt; m > 0; ++rp)
+	if ((--m & mask) != 0)
+	  rp->len += temp[n].len + 1;
+    }
+  while (n != 0);
+
+  /* The first half of the strings all include the first string.  */
+  n = (1 << cnt) - 2;
+  rp = &result[2];
+  while (n != (1UL << (cnt - 1)))
+    {
+      if ((--n & 1) != 0)
+	rp[0].str = rp[-2].str + rp[-2].len;
+      else
+	rp[0].str = rp[-1].str;
+      ++rp;
+    }
+
+  /* The second half starts right after the first part of the string of
+     the corresponding entry in the first half.  */
+  do
+    {
+      rp[0].str = rp[-(1 << (cnt - 1))].str + temp[cnt - 1].len + 1;
+      ++rp;
+    }
+  while (--n != 0);
+
+  /* The maximum string length.  */
+  *max_capstrlen = result[0].len;
+
+  return result;
+}