/* Handle #pragma, system V.4 style. Supports #pragma weak and #pragma pack.
- Copyright (C) 1992, 1997 Free Software Foundation, Inc.
+ Copyright (C) 1992, 1997, 1998, 1999, 2000, 2001
+ Free Software Foundation, Inc.
This file is part of GNU CC.
Boston, MA 02111-1307, USA. */
#include "config.h"
-#include <stdio.h>
+#include "system.h"
+#include "rtl.h"
#include "tree.h"
-#include "except.h"
#include "function.h"
-#include "defaults.h"
+#include "cpplib.h"
#include "c-pragma.h"
#include "flags.h"
+#include "toplev.h"
+#include "ggc.h"
+#include "c-lex.h"
+#include "tm_p.h"
-#ifdef HANDLE_SYSV_PRAGMA
+#define BAD(msgid) do { warning (msgid); return; } while (0)
+#define BAD2(msgid, arg) do { warning (msgid, arg); return; } while (0)
-/* When structure field packing is in effect, this variable is the
- number of bits to use as the maximum alignment. When packing is not
- in effect, this is zero. */
+#ifdef HANDLE_PRAGMA_PACK
+static void handle_pragma_pack PARAMS ((cpp_reader *));
-extern int maximum_field_alignment;
+#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
+typedef struct align_stack
+{
+ int alignment;
+ unsigned int num_pushes;
+ tree id;
+ struct align_stack * prev;
+} align_stack;
-/* File used for outputting assembler code. */
-extern FILE *asm_out_file;
+static struct align_stack * alignment_stack = NULL;
-/* Handle one token of a pragma directive. TOKEN is the
- current token, and STRING is its printable form. */
+/* If we have a "global" #pragma pack(<n>) in effect when the first
+ #pragma pack(push,<n>) is encountered, this stores the value of
+ maximum_field_alignment in effect. When the final pop_alignment()
+ happens, we restore the value to this, not to a value of 0 for
+ maximum_field_alignment. Value is in bits. */
+static int default_alignment;
+#define SET_GLOBAL_ALIGNMENT(ALIGN) \
+(default_alignment = maximum_field_alignment = (ALIGN))
-void
-handle_pragma_token (string, token)
- char *string;
- tree token;
-{
- static enum pragma_state state = ps_start, type;
- static char *name;
- static char *value;
- static int align;
+static void push_alignment PARAMS ((int, tree));
+static void pop_alignment PARAMS ((tree));
+static void mark_align_stack PARAMS ((void *));
- if (string == 0)
+/* Push an alignment value onto the stack. */
+static void
+push_alignment (alignment, id)
+ int alignment;
+ tree id;
+{
+
+ if (alignment_stack == NULL
+ || alignment_stack->alignment != alignment
+ || id != NULL_TREE)
{
- if (type == ps_pack)
- {
- if (state == ps_right)
- maximum_field_alignment = align * 8;
- else
- warning ("malformed `#pragma pack'");
- }
- else if (type == ps_weak)
- {
-#ifdef HANDLE_PRAGMA_WEAK
- if (HANDLE_PRAGMA_WEAK)
- handle_pragma_weak (state, name, value);
+ align_stack * entry;
-#endif /* HANDLE_PRAGMA_WEAK */
- }
+ entry = (align_stack *) xmalloc (sizeof (* entry));
+
+ entry->alignment = alignment;
+ entry->num_pushes = 1;
+ entry->id = id;
+ entry->prev = alignment_stack;
+
+ /* The current value of maximum_field_alignment is not necessarily
+ 0 since there may be a #pragma pack(<n>) in effect; remember it
+ so that we can restore it after the final #pragma pop(). */
+ if (alignment_stack == NULL)
+ default_alignment = maximum_field_alignment;
+
+ alignment_stack = entry;
- type = state = ps_start;
+ maximum_field_alignment = alignment;
+ }
+ else
+ alignment_stack->num_pushes ++;
+}
+
+/* Undo a push of an alignment onto the stack. */
+static void
+pop_alignment (id)
+ tree id;
+{
+ align_stack * entry;
+
+ if (alignment_stack == NULL)
+ {
+ warning ("\
+#pragma pack (pop) encountered without matching #pragma pack (push, <n>)"
+ );
return;
}
- switch (state)
+ /* If we got an identifier, strip away everything above the target
+ entry so that the next step will restore the state just below it. */
+ if (id)
{
- case ps_start:
- if (token && TREE_CODE (token) == IDENTIFIER_NODE)
- {
- if (strcmp (IDENTIFIER_POINTER (token), "pack") == 0)
- type = state = ps_pack;
- else if (strcmp (IDENTIFIER_POINTER (token), "weak") == 0)
- type = state = ps_weak;
- else
- {
- type = state = ps_done;
-
- /* Issue a warning message if we have been asked to do so.
- Ignoring unknown pragmas in system header file unless
- an explcit -Wunknown-pragmas has been given. */
- if (warn_unknown_pragmas > 1
- || (warn_unknown_pragmas && ! in_system_header))
- warning ("ignoring pragma: %s", string);
- }
- }
- else
- type = state = ps_done;
- break;
+ for (entry = alignment_stack; entry; entry = entry->prev)
+ if (entry->id == id)
+ {
+ entry->num_pushes = 1;
+ alignment_stack = entry;
+ break;
+ }
+ if (entry == NULL)
+ warning ("\
+#pragma pack(pop, %s) encountered without matching #pragma pack(push, %s, <n>)"
+ , IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
+ }
- case ps_weak:
- if (token && TREE_CODE (token) == IDENTIFIER_NODE)
- {
- name = IDENTIFIER_POINTER (token);
- state = ps_name;
- }
+ if (-- alignment_stack->num_pushes == 0)
+ {
+ entry = alignment_stack->prev;
+
+ if (entry == NULL)
+ maximum_field_alignment = default_alignment;
else
- state = ps_bad;
- break;
+ maximum_field_alignment = entry->alignment;
- case ps_name:
- state = (strcmp (string, "=") ? ps_bad : ps_equals);
- break;
+ free (alignment_stack);
- case ps_equals:
- if (token && TREE_CODE (token) == IDENTIFIER_NODE)
- {
- value = IDENTIFIER_POINTER (token);
- state = ps_value;
- }
- else
- state = ps_bad;
- break;
+ alignment_stack = entry;
+ }
+}
- case ps_value:
- state = ps_bad;
- break;
+static void
+mark_align_stack (p)
+ void *p;
+{
+ align_stack *a = *(align_stack **) p;
+
+ while (a)
+ {
+ ggc_mark_tree (a->id);
+ a = a->prev;
+ }
+}
+#else /* not HANDLE_PRAGMA_PACK_PUSH_POP */
+#define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = (ALIGN))
+#define push_alignment(ID, N) \
+ BAD("#pragma pack(push[, id], <n>) is not supported on this target")
+#define pop_alignment(ID) \
+ BAD("#pragma pack(pop[, id], <n>) is not supported on this target")
+#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
- case ps_pack:
- if (strcmp (string, "(") == 0)
- state = ps_left;
+/* #pragma pack ()
+ #pragma pack (N)
+
+ #pragma pack (push, N)
+ #pragma pack (push, ID, N)
+ #pragma pack (pop)
+ #pragma pack (pop, ID) */
+static void
+handle_pragma_pack (dummy)
+ cpp_reader *dummy ATTRIBUTE_UNUSED;
+{
+ tree x, id = 0;
+ int align = -1;
+ enum cpp_ttype token;
+ enum { set, push, pop } action;
+
+ if (c_lex (&x) != CPP_OPEN_PAREN)
+ BAD ("missing '(' after '#pragma pack' - ignored");
+
+ token = c_lex (&x);
+ if (token == CPP_CLOSE_PAREN)
+ {
+ action = set;
+ align = 0;
+ }
+ else if (token == CPP_NUMBER)
+ {
+ align = TREE_INT_CST_LOW (x);
+ action = set;
+ if (c_lex (&x) != CPP_CLOSE_PAREN)
+ BAD ("malformed '#pragma pack' - ignored");
+ }
+ else if (token == CPP_NAME)
+ {
+#define BAD_ACTION do { if (action == push) \
+ BAD ("malformed '#pragma pack(push[, id], <n>)' - ignored"); \
+ else \
+ BAD ("malformed '#pragma pack(pop[, id])' - ignored"); \
+ } while (0)
+
+ const char *op = IDENTIFIER_POINTER (x);
+ if (!strcmp (op, "push"))
+ action = push;
+ else if (!strcmp (op, "pop"))
+ action = pop;
else
- state = ps_bad;
- break;
+ BAD2 ("unknown action '%s' for '#pragma pack' - ignored", op);
- case ps_left:
- if (token && TREE_CODE (token) == INTEGER_CST
- && TREE_INT_CST_HIGH (token) == 0)
- switch (TREE_INT_CST_LOW (token))
- {
- case 1:
- case 2:
- case 4:
- align = TREE_INT_CST_LOW (token);
- state = ps_align;
- break;
+ token = c_lex (&x);
+ if (token != CPP_COMMA && action == push)
+ BAD_ACTION;
- default:
- state = ps_bad;
- }
- else if (! token && strcmp (string, ")") == 0)
+ if (token == CPP_COMMA)
{
- align = 0;
- state = ps_right;
+ token = c_lex (&x);
+ if (token == CPP_NAME)
+ {
+ id = x;
+ if (action == push && c_lex (&x) != CPP_COMMA)
+ BAD_ACTION;
+ token = c_lex (&x);
+ }
+
+ if (action == push)
+ {
+ if (token == CPP_NUMBER)
+ {
+ align = TREE_INT_CST_LOW (x);
+ token = c_lex (&x);
+ }
+ else
+ BAD_ACTION;
+ }
}
- else
- state = ps_bad;
- break;
- case ps_align:
- if (strcmp (string, ")") == 0)
- state = ps_right;
- else
- state = ps_bad;
- break;
+ if (token != CPP_CLOSE_PAREN)
+ BAD_ACTION;
+#undef BAD_ACTION
+ }
+ else
+ BAD ("malformed '#pragma pack' - ignored");
+
+ if (c_lex (&x) != CPP_EOF)
+ warning ("junk at end of '#pragma pack'");
+
+ if (action != pop)
+ switch (align)
+ {
+ case 0:
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ case 16:
+ align *= BITS_PER_UNIT;
+ break;
+ default:
+ BAD2 ("alignment must be a small power of two, not %d", align);
+ }
+
+ switch (action)
+ {
+ case set: SET_GLOBAL_ALIGNMENT (align); break;
+ case push: push_alignment (align, id); break;
+ case pop: pop_alignment (id); break;
+ }
+}
+#endif /* HANDLE_PRAGMA_PACK */
+
+#ifdef HANDLE_PRAGMA_WEAK
+static void handle_pragma_weak PARAMS ((cpp_reader *));
- case ps_right:
- state = ps_bad;
- break;
+/* #pragma weak name [= value] */
+static void
+handle_pragma_weak (dummy)
+ cpp_reader *dummy ATTRIBUTE_UNUSED;
+{
+ tree name, value, x;
+ enum cpp_ttype t;
- case ps_bad:
- case ps_done:
- break;
+ value = 0;
- default:
- abort ();
+ if (c_lex (&name) != CPP_NAME)
+ BAD ("malformed #pragma weak, ignored");
+ t = c_lex (&x);
+ if (t == CPP_EQ)
+ {
+ if (c_lex (&value) != CPP_NAME)
+ BAD ("malformed #pragma weak, ignored");
+ t = c_lex (&x);
}
+ if (t != CPP_EOF)
+ warning ("junk at end of #pragma weak");
+
+ add_weak (IDENTIFIER_POINTER (name), value ? IDENTIFIER_POINTER (value) : 0);
+}
+#endif
+
+void
+init_pragma ()
+{
+#ifdef HANDLE_PRAGMA_PACK
+ cpp_register_pragma (parse_in, 0, "pack", handle_pragma_pack);
+#endif
+#ifdef HANDLE_PRAGMA_WEAK
+ cpp_register_pragma (parse_in, 0, "weak", handle_pragma_weak);
+#endif
+#ifdef REGISTER_TARGET_PRAGMAS
+ REGISTER_TARGET_PRAGMAS (parse_in);
+#endif
+
+#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
+ ggc_add_root (&alignment_stack, 1, sizeof(alignment_stack),
+ mark_align_stack);
+#endif
}
-#endif /* HANDLE_SYSV_PRAGMA */
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