102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
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/* go-fieldtrack.c -- structure field data analysis.
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Copyright 2012 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include "runtime.h"
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#include "go-type.h"
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#include "map.h"
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/* The compiler will track fields that have the tag go:"track". Any
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function that refers to such a field will call this function with a
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string
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fieldtrack "package.type.field"
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This function does not actually do anything. Instead, we gather
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the field tracking information by looking for strings of that form
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in the read-only data section. This is, of course, a horrible
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hack, but it's good enough for now. We can improve it, e.g., by a
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linker plugin, if this turns out to be useful. */
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void
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__go_fieldtrack (byte *p __attribute__ ((unused)))
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{
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}
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/* A runtime function to add all the tracked fields to a
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map[string]bool. */
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extern const char _etext[] __attribute__ ((weak));
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extern const char __etext[] __attribute__ ((weak));
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extern const char __data_start[] __attribute__ ((weak));
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extern const char _edata[] __attribute__ ((weak));
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extern const char __edata[] __attribute__ ((weak));
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extern const char __bss_start[] __attribute__ ((weak));
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void runtime_Fieldtrack (struct __go_map *) __asm__ ("runtime.Fieldtrack");
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void
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runtime_Fieldtrack (struct __go_map *m)
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{
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const char *p;
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const char *pend;
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const char *prefix;
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size_t prefix_len;
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p = __data_start;
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if (p == NULL)
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p = __etext;
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if (p == NULL)
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p = _etext;
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if (p == NULL)
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return;
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pend = __edata;
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if (pend == NULL)
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pend = _edata;
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if (pend == NULL)
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pend = __bss_start;
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if (pend == NULL)
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return;
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prefix = "fieldtrack ";
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prefix_len = __builtin_strlen (prefix);
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while (p < pend)
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{
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const char *q1;
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const char *q2;
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q1 = __builtin_memchr (p + prefix_len, '"', pend - (p + prefix_len));
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if (q1 == NULL)
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break;
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if (__builtin_memcmp (q1 - prefix_len, prefix, prefix_len) != 0)
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{
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p = q1 + 1;
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continue;
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}
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q1++;
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q2 = __builtin_memchr (q1, '"', pend - q1);
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if (q2 == NULL)
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break;
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if (__builtin_memchr (q1, '\0', q2 - q1) == NULL)
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{
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String s;
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void *v;
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_Bool *pb;
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s.str = (const byte *) q1;
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s.len = q2 - q1;
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v = __go_map_index (m, &s, 1);
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pb = (_Bool *) v;
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*pb = 1;
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}
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p = q2;
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}
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}
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