Merge GDB 7.5.1

gdb/gnulib/import/alloca.c

 /* alloca.c -- allocate automatically reclaimed memory
    (Mostly) portable public-domain implementation -- D A Gwyn
 
    This implementation of the PWB library alloca function,
    which is used to allocate space off the run-time stack so
    that it is automatically reclaimed upon procedure exit,
    was inspired by discussions with J. Q. Johnson of Cornell.
    J.Otto Tennant <jot@cray.com> contributed the Cray support.
 
    There are some preprocessor constants that can
    be defined when compiling for your specific system, for
    improved efficiency; however, the defaults should be okay.
 
    The general concept of this implementation is to keep
    track of all alloca-allocated blocks, and reclaim any
    that are found to be deeper in the stack than the current
    invocation.  This heuristic does not reclaim storage as
    soon as it becomes invalid, but it will do so eventually.
 
    As a special case, alloca(0) reclaims storage without
    allocating any.  It is a good idea to use alloca(0) in
    your main control loop, etc. to force garbage collection.  */
 
-/*
+#include <config.h>
 
-@deftypefn Replacement void* alloca (size_t @var{size})
+#include <alloca.h>
 
-This function allocates memory which will be automatically reclaimed
-after the procedure exits.  The @libib{} implementation does not free
-the memory immediately but will do so eventually during subsequent
-calls to this function.  Memory is allocated using @code{xmalloc} under
-normal circumstances.
+#include <string.h>
+#include <stdlib.h>
 
-The header file @file{alloca-conf.h} can be used in conjunction with the
-GNU Autoconf test @code{AC_FUNC_ALLOCA} to test for and properly make
-available this function.  The @code{AC_FUNC_ALLOCA} test requires that
-client code use a block of preprocessor code to be safe (see the Autoconf
-manual for more); this header incorporates that logic and more, including
-the possibility of a GCC built-in function.
-
-@end deftypefn
-
-*/
-
-#ifdef HAVE_CONFIG_H
-#include <config.h>
+#ifdef emacs
+# include "lisp.h"
+# include "blockinput.h"
+# ifdef EMACS_FREE
+#  undef free
+#  define free EMACS_FREE
+# endif
+#else
+# define memory_full() abort ()
 #endif
 
-#include <libiberty.h>
+/* If compiling with GCC 2, this file's not needed.  */
+#if !defined (__GNUC__) || __GNUC__ < 2
 
-#ifdef HAVE_STRING_H
-#include <string.h>
-#endif
-#ifdef HAVE_STDLIB_H
-#include <stdlib.h>
-#endif
+/* If someone has defined alloca as a macro,
+   there must be some other way alloca is supposed to work.  */
+# ifndef alloca
 
-/* These variables are used by the ASTRDUP implementation that relies
-   on C_alloca.  */
-#ifdef __cplusplus
-extern "C" {
-#endif /* __cplusplus */
-const char *libiberty_optr;
-char *libiberty_nptr;
-unsigned long libiberty_len;
-#ifdef __cplusplus
-}
-#endif /* __cplusplus */
+#  ifdef emacs
+#   ifdef static
+/* actually, only want this if static is defined as ""
+   -- this is for usg, in which emacs must undefine static
+   in order to make unexec workable
+   */
+#    ifndef STACK_DIRECTION
+you
+lose
+-- must know STACK_DIRECTION at compile-time
+/* Using #error here is not wise since this file should work for
+   old and obscure compilers.  */
+#    endif /* STACK_DIRECTION undefined */
+#   endif /* static */
+#  endif /* emacs */
 
 /* If your stack is a linked list of frames, you have to
    provide an "address metric" ADDRESS_FUNCTION macro.  */
 
-#if defined (CRAY) && defined (CRAY_STACKSEG_END)
-static long i00afunc ();
-#define ADDRESS_FUNCTION(arg) (char *) i00afunc (&(arg))
-#else
-#define ADDRESS_FUNCTION(arg) &(arg)
-#endif
-
-#ifndef NULL
-#define NULL    0
-#endif
+#  if defined (CRAY) && defined (CRAY_STACKSEG_END)
+long i00afunc ();
+#   define ADDRESS_FUNCTION(arg) (char *) i00afunc (&(arg))
+#  else
+#   define ADDRESS_FUNCTION(arg) &(arg)
+#  endif
 
 /* Define STACK_DIRECTION if you know the direction of stack
    growth for your system; otherwise it will be automatically
    deduced at run-time.
 
    STACK_DIRECTION > 0 => grows toward higher addresses
    STACK_DIRECTION < 0 => grows toward lower addresses
    STACK_DIRECTION = 0 => direction of growth unknown  */
 
-#ifndef STACK_DIRECTION
-#define STACK_DIRECTION 0       /* Direction unknown.  */
-#endif
+#  ifndef STACK_DIRECTION
+#   define STACK_DIRECTION      0       /* Direction unknown.  */
+#  endif
 
-#if STACK_DIRECTION != 0
+#  if STACK_DIRECTION != 0
 
-#define STACK_DIR       STACK_DIRECTION /* Known at compile-time.  */
+#   define STACK_DIR    STACK_DIRECTION /* Known at compile-time.  */
 
-#else /* STACK_DIRECTION == 0; need run-time code.  */
+#  else /* STACK_DIRECTION == 0; need run-time code.  */
 
-static int stack_dir;           /* 1 or -1 once known.  */
-#define STACK_DIR       stack_dir
+static int stack_dir;           /* 1 or -1 once known.  */
+#   define STACK_DIR    stack_dir
 
-static void
-find_stack_direction (void)
+static int
+find_stack_direction (int *addr, int depth)
 {
-  static char *addr = NULL;     /* Address of first `dummy', once known.  */
-  auto char dummy;              /* To get stack address.  */
-
-  if (addr == NULL)
-    {                           /* Initial entry.  */
-      addr = ADDRESS_FUNCTION (dummy);
-
-      find_stack_direction ();  /* Recurse once.  */
-    }
-  else
-    {
-      /* Second entry.  */
-      if (ADDRESS_FUNCTION (dummy) > addr)
-        stack_dir = 1;          /* Stack grew upward.  */
-      else
-        stack_dir = -1;         /* Stack grew downward.  */
-    }
+  int dir, dummy = 0;
+  if (! addr)
+    addr = &dummy;
+  *addr = addr < &dummy ? 1 : addr == &dummy ? 0 : -1;
+  dir = depth ? find_stack_direction (addr, depth - 1) : 0;
+  return dir + dummy;
 }
 
-#endif /* STACK_DIRECTION == 0 */
+#  endif /* STACK_DIRECTION == 0 */
 
 /* An "alloca header" is used to:
    (a) chain together all alloca'ed blocks;
    (b) keep track of stack depth.
 
    It is very important that sizeof(header) agree with malloc
    alignment chunk size.  The following default should work okay.  */
 
-#ifndef ALIGN_SIZE
-#define ALIGN_SIZE      sizeof(double)
-#endif
+#  ifndef       ALIGN_SIZE
+#   define ALIGN_SIZE   sizeof(double)
+#  endif
 
 typedef union hdr
 {
-  char align[ALIGN_SIZE];       /* To force sizeof(header).  */
+  char align[ALIGN_SIZE];       /* To force sizeof(header).  */
   struct
     {
-      union hdr *next;          /* For chaining headers.  */
-      char *deep;               /* For stack depth measure.  */
+      union hdr *next;          /* For chaining headers.  */
+      char *deep;               /* For stack depth measure.  */
     } h;
 } header;
 
-static header *last_alloca_header = NULL;       /* -> last alloca header.  */
+static header *last_alloca_header = NULL;       /* -> last alloca header.  */
 
 /* Return a pointer to at least SIZE bytes of storage,
    which will be automatically reclaimed upon exit from
    the procedure that called alloca.  Originally, this space
    was supposed to be taken from the current stack frame of the
    caller, but that method cannot be made to work for some
    implementations of C, for example under Gould's UTX/32.  */
 
-/* @undocumented C_alloca */
-
-PTR
-C_alloca (size_t size)
+void *
+alloca (size_t size)
 {
-  auto char probe;              /* Probes stack depth: */
+  auto char probe;              /* Probes stack depth: */
   register char *depth = ADDRESS_FUNCTION (probe);
 
-#if STACK_DIRECTION == 0
-  if (STACK_DIR == 0)           /* Unknown growth direction.  */
-    find_stack_direction ();
-#endif
+#  if STACK_DIRECTION == 0
+  if (STACK_DIR == 0)           /* Unknown growth direction.  */
+    STACK_DIR = find_stack_direction (NULL, (size & 1) + 20);
+#  endif
 
   /* Reclaim garbage, defined as all alloca'd storage that
      was allocated from deeper in the stack than currently.  */
 
   {
-    register header *hp;        /* Traverses linked list.  */
+    register header *hp;        /* Traverses linked list.  */
+
+#  ifdef emacs
+    BLOCK_INPUT;
+#  endif
 
     for (hp = last_alloca_header; hp != NULL;)
       if ((STACK_DIR > 0 && hp->h.deep > depth)
-          || (STACK_DIR < 0 && hp->h.deep < depth))
-        {
-          register header *np = hp->h.next;
+          || (STACK_DIR < 0 && hp->h.deep < depth))
+        {
+          register header *np = hp->h.next;
 
-          free ((PTR) hp);      /* Collect garbage.  */
+          free (hp);            /* Collect garbage.  */
 
-          hp = np;              /* -> next header.  */
-        }
+          hp = np;              /* -> next header.  */
+        }
       else
-        break;                  /* Rest are not deeper.  */
+        break;                  /* Rest are not deeper.  */
 
-    last_alloca_header = hp;    /* -> last valid storage.  */
+    last_alloca_header = hp;    /* -> last valid storage.  */
+
+#  ifdef emacs
+    UNBLOCK_INPUT;
+#  endif
   }
 
   if (size == 0)
-    return NULL;                /* No allocation required.  */
+    return NULL;                /* No allocation required.  */
 
   /* Allocate combined header + user data storage.  */
 
   {
-    register void *new_storage = XNEWVEC (char, sizeof (header) + size);
     /* Address of header.  */
+    register header *new;
 
-    if (new_storage == 0)
-      abort();
+    size_t combined_size = sizeof (header) + size;
+    if (combined_size < sizeof (header))
+      memory_full ();
 
-    ((header *) new_storage)->h.next = last_alloca_header;
-    ((header *) new_storage)->h.deep = depth;
+    new = malloc (combined_size);
 
-    last_alloca_header = (header *) new_storage;
+    if (! new)
+      memory_full ();
+
+    new->h.next = last_alloca_header;
+    new->h.deep = depth;
+
+    last_alloca_header = new;
 
     /* User storage begins just after header.  */
 
-    return (PTR) ((char *) new_storage + sizeof (header));
+    return (void *) (new + 1);
   }
 }
 
-#if defined (CRAY) && defined (CRAY_STACKSEG_END)
+#  if defined (CRAY) && defined (CRAY_STACKSEG_END)
 
-#ifdef DEBUG_I00AFUNC
-#include <stdio.h>
-#endif
+#   ifdef DEBUG_I00AFUNC
+#    include <stdio.h>
+#   endif
 
-#ifndef CRAY_STACK
-#define CRAY_STACK
-#ifndef CRAY2
+#   ifndef CRAY_STACK
+#    define CRAY_STACK
+#    ifndef CRAY2
 /* Stack structures for CRAY-1, CRAY X-MP, and CRAY Y-MP */
 struct stack_control_header
   {
-    long shgrow:32;             /* Number of times stack has grown.  */
-    long shaseg:32;             /* Size of increments to stack.  */
-    long shhwm:32;              /* High water mark of stack.  */
-    long shsize:32;             /* Current size of stack (all segments).  */
+    long shgrow:32;             /* Number of times stack has grown.  */
+    long shaseg:32;             /* Size of increments to stack.  */
+    long shhwm:32;              /* High water mark of stack.  */
+    long shsize:32;             /* Current size of stack (all segments).  */
   };
 
 /* The stack segment linkage control information occurs at
    the high-address end of a stack segment.  (The stack
    grows from low addresses to high addresses.)  The initial
    part of the stack segment linkage control information is
    0200 (octal) words.  This provides for register storage
    for the routine which overflows the stack.  */
 
 struct stack_segment_linkage
   {
-    long ss[0200];              /* 0200 overflow words.  */
-    long sssize:32;             /* Number of words in this segment.  */
-    long ssbase:32;             /* Offset to stack base.  */
+    long ss[0200];              /* 0200 overflow words.  */
+    long sssize:32;             /* Number of words in this segment.  */
+    long ssbase:32;             /* Offset to stack base.  */
     long:32;
-    long sspseg:32;             /* Offset to linkage control of previous
-                                   segment of stack.  */
+    long sspseg:32;             /* Offset to linkage control of previous
+                                   segment of stack.  */
     long:32;
-    long sstcpt:32;             /* Pointer to task common address block.  */
-    long sscsnm;                /* Private control structure number for
-                                   microtasking.  */
-    long ssusr1;                /* Reserved for user.  */
-    long ssusr2;                /* Reserved for user.  */
-    long sstpid;                /* Process ID for pid based multi-tasking.  */
-    long ssgvup;                /* Pointer to multitasking thread giveup.  */
-    long sscray[7];             /* Reserved for Cray Research.  */
+    long sstcpt:32;             /* Pointer to task common address block.  */
+    long sscsnm;                /* Private control structure number for
+                                   microtasking.  */
+    long ssusr1;                /* Reserved for user.  */
+    long ssusr2;                /* Reserved for user.  */
+    long sstpid;                /* Process ID for pid based multi-tasking.  */
+    long ssgvup;                /* Pointer to multitasking thread giveup.  */
+    long sscray[7];             /* Reserved for Cray Research.  */
     long ssa0;
     long ssa1;
     long ssa2;
     long ssa3;
     long ssa4;
     long ssa5;
     long ssa6;
     long ssa7;
     long sss0;
     long sss1;
     long sss2;
     long sss3;
     long sss4;
     long sss5;
     long sss6;
     long sss7;
   };
 
-#else /* CRAY2 */
+#    else /* CRAY2 */
 /* The following structure defines the vector of words
    returned by the STKSTAT library routine.  */
 struct stk_stat
   {
-    long now;                   /* Current total stack size.  */
-    long maxc;                  /* Amount of contiguous space which would
-                                   be required to satisfy the maximum
-                                   stack demand to date.  */
-    long high_water;            /* Stack high-water mark.  */
-    long overflows;             /* Number of stack overflow ($STKOFEN) calls.  */
-    long hits;                  /* Number of internal buffer hits.  */
-    long extends;               /* Number of block extensions.  */
-    long stko_mallocs;          /* Block allocations by $STKOFEN.  */
-    long underflows;            /* Number of stack underflow calls ($STKRETN).  */
-    long stko_free;             /* Number of deallocations by $STKRETN.  */
-    long stkm_free;             /* Number of deallocations by $STKMRET.  */
-    long segments;              /* Current number of stack segments.  */
-    long maxs;                  /* Maximum number of stack segments so far.  */
-    long pad_size;              /* Stack pad size.  */
-    long current_address;       /* Current stack segment address.  */
-    long current_size;          /* Current stack segment size.  This
-                                   number is actually corrupted by STKSTAT to
-                                   include the fifteen word trailer area.  */
-    long initial_address;       /* Address of initial segment.  */
-    long initial_size;          /* Size of initial segment.  */
+    long now;                   /* Current total stack size.  */
+    long maxc;                  /* Amount of contiguous space which would
+                                   be required to satisfy the maximum
+                                   stack demand to date.  */
+    long high_water;            /* Stack high-water mark.  */
+    long overflows;             /* Number of stack overflow ($STKOFEN) calls.  */
+    long hits;                  /* Number of internal buffer hits.  */
+    long extends;               /* Number of block extensions.  */
+    long stko_mallocs;          /* Block allocations by $STKOFEN.  */
+    long underflows;            /* Number of stack underflow calls ($STKRETN).  */
+    long stko_free;             /* Number of deallocations by $STKRETN.  */
+    long stkm_free;             /* Number of deallocations by $STKMRET.  */
+    long segments;              /* Current number of stack segments.  */
+    long maxs;                  /* Maximum number of stack segments so far.  */
+    long pad_size;              /* Stack pad size.  */
+    long current_address;       /* Current stack segment address.  */
+    long current_size;          /* Current stack segment size.  This
+                                   number is actually corrupted by STKSTAT to
+                                   include the fifteen word trailer area.  */
+    long initial_address;       /* Address of initial segment.  */
+    long initial_size;          /* Size of initial segment.  */
   };
 
 /* The following structure describes the data structure which trails
    any stack segment.  I think that the description in 'asdef' is
    out of date.  I only describe the parts that I am sure about.  */
 
 struct stk_trailer
   {
-    long this_address;          /* Address of this block.  */
-    long this_size;             /* Size of this block (does not include
-                                   this trailer).  */
+    long this_address;          /* Address of this block.  */
+    long this_size;             /* Size of this block (does not include
+                                   this trailer).  */
     long unknown2;
     long unknown3;
-    long link;                  /* Address of trailer block of previous
-                                   segment.  */
+    long link;                  /* Address of trailer block of previous
+                                   segment.  */
     long unknown5;
     long unknown6;
     long unknown7;
     long unknown8;
     long unknown9;
     long unknown10;
     long unknown11;
     long unknown12;
     long unknown13;
     long unknown14;
   };
 
-#endif /* CRAY2 */
-#endif /* not CRAY_STACK */
+#    endif /* CRAY2 */
+#   endif /* not CRAY_STACK */
 
-#ifdef CRAY2
+#   ifdef CRAY2
 /* Determine a "stack measure" for an arbitrary ADDRESS.
    I doubt that "lint" will like this much.  */
 
 static long
 i00afunc (long *address)
 {
   struct stk_stat status;
   struct stk_trailer *trailer;
   long *block, size;
   long result = 0;
 
   /* We want to iterate through all of the segments.  The first
      step is to get the stack status structure.  We could do this
      more quickly and more directly, perhaps, by referencing the
      $LM00 common block, but I know that this works.  */
 
   STKSTAT (&status);
 
   /* Set up the iteration.  */
 
   trailer = (struct stk_trailer *) (status.current_address
-                                    + status.current_size
-                                    - 15);
+                                    + status.current_size
+                                    - 15);
 
   /* There must be at least one stack segment.  Therefore it is
      a fatal error if "trailer" is null.  */
 
   if (trailer == 0)
     abort ();
 
   /* Discard segments that do not contain our argument address.  */
 
   while (trailer != 0)
     {
       block = (long *) trailer->this_address;
       size = trailer->this_size;
       if (block == 0 || size == 0)
-        abort ();
+        abort ();
       trailer = (struct stk_trailer *) trailer->link;
       if ((block <= address) && (address < (block + size)))
-        break;
+        break;
     }
 
   /* Set the result to the offset in this segment and add the sizes
      of all predecessor segments.  */
 
   result = address - block;
 
   if (trailer == 0)
     {
       return result;
     }
 
   do
     {
       if (trailer->this_size <= 0)
-        abort ();
+        abort ();
       result += trailer->this_size;
       trailer = (struct stk_trailer *) trailer->link;
     }
   while (trailer != 0);
 
   /* We are done.  Note that if you present a bogus address (one
      not in any segment), you will get a different number back, formed
      from subtracting the address of the first block.  This is probably
      not what you want.  */
 
   return (result);
 }
 
-#else /* not CRAY2 */
+#   else /* not CRAY2 */
 /* Stack address function for a CRAY-1, CRAY X-MP, or CRAY Y-MP.
    Determine the number of the cell within the stack,
    given the address of the cell.  The purpose of this
    routine is to linearize, in some sense, stack addresses
    for alloca.  */
 
 static long
 i00afunc (long address)
 {
   long stkl = 0;
@@ skipping 24 matching lines @@
   size = ssptr->sssize;
 
   this_segment = stkl - size;
 
   /* It is possible that calling this routine itself caused
      a stack overflow.  Discard stack segments which do not
      contain the target address.  */
 
   while (!(this_segment <= address && address <= stkl))
     {
-#ifdef DEBUG_I00AFUNC
+#    ifdef DEBUG_I00AFUNC
       fprintf (stderr, "%011o %011o %011o\n", this_segment, address, stkl);
-#endif
+#    endif
       if (pseg == 0)
-        break;
+        break;
       stkl = stkl - pseg;
       ssptr = (struct stack_segment_linkage *) stkl;
       size = ssptr->sssize;
       pseg = ssptr->sspseg;
       this_segment = stkl - size;
     }
 
   result = address - this_segment;
 
   /* If you subtract pseg from the current end of the stack,
      you get the address of the previous stack segment's end.
      This seems a little convoluted to me, but I'll bet you save
      a cycle somewhere.  */
 
   while (pseg != 0)
     {
-#ifdef DEBUG_I00AFUNC
+#    ifdef DEBUG_I00AFUNC
       fprintf (stderr, "%011o %011o\n", pseg, size);
-#endif
+#    endif
       stkl = stkl - pseg;
       ssptr = (struct stack_segment_linkage *) stkl;
       size = ssptr->sssize;
       pseg = ssptr->sspseg;
       result += size;
     }
   return (result);
 }
 
-#endif /* not CRAY2 */
-#endif /* CRAY */
+#   endif /* not CRAY2 */
+#  endif /* CRAY */
+
+# endif /* no alloca */
+#endif /* not GCC 2 */