frontend: basic #include

5 files changed, 118 insertions, 7 deletions

diff --git a/c.c b/c.c
index 92075a3..b09fc08 100644
--- a/c.c
+++ b/c.c
@@ -3428,7 +3428,7 @@ ccomp(const char *file)
    static union { char m[sizeof(struct arena) + N]; struct arena *_align; } amem[2];
    struct comp cm = {0};
 
-   initlexer(&cm.lx, file, &cm.exarena);
+   initlexer(&cm.lx, NULL, file, &cm.exarena);
    cm.fnarena = (void *)amem[0].m;
    cm.fnarena->cap = N;
    cm.exarena = (void *)amem[1].m;
diff --git a/lex.c b/lex.c
index 924cfe4..a74fe60 100644
--- a/lex.c
+++ b/lex.c
@@ -366,6 +366,40 @@ readstrchrlit(struct lexer *lx, struct token *tk, char delim)
    vfree(&b);
 }
 
+/* for #include directive, read "header" or <header> */
+static void
+readheadername(struct lexer *lx, struct token *tk, char delim)
+{
+   int c;
+   uchar tmp[80];
+   vec_of(uchar) b = VINIT(tmp, sizeof tmp);
+   struct span span = {0};
+   uint beginoff, idx;
+   beginoff = idx = lx->chridx;
+
+   while ((c = next(lx)) != delim) {
+      if (c == '\n' || c == TKEOF) {
+         span.sl = (struct span0) { idx, lx->chridx - idx, lx->fileid };
+         error(&span, "missing terminating %c character", delim);
+         break;
+      }
+      vpush(&b, c);
+      idx = lx->chridx;;
+   }
+   tk->t = delim == '"' ? TKPPHDRQ : TKPPHDRH;
+   tk->len = b.n;
+   if (lx->chridx - beginoff == tk->len + 1) {
+      tk->litlit = 1;
+      tk->s = (char *)&lx->dat[beginoff];
+   } else {
+      tk->litlit = 0;
+      vpush(&b, 0);
+      tk->s = alloc(lx->tmparena, b.n, 1);
+      memcpy((char *)tk->s, b.p, b.n);
+   }
+   vfree(&b);
+}
+
 /* matches "<digit> | <identifier-nondigit> | '.' | ([eEpP][+-])" */
 static bool
 isppnum(char prev, char c)
@@ -377,6 +411,9 @@ isppnum(char prev, char c)
    return 0;
 }
 
+/* special mode to parse header path for #include */
+static bool lexingheadername = 0;
+
 static int
 lex0(struct lexer *lx, struct token *tk)
 {
@@ -443,6 +480,11 @@ Begin:
       if (match(lx, '=')) RET(TKEQU);
       RET(c);
    case '<':
+      if (lexingheadername) {
+         readheadername(lx, tk, '>');
+         lexingheadername = 0;
+         goto End;
+      }
       if (match(lx, '=')) RET(TKLTE);
       if (match(lx, '<')) RET(match(lx, '=') ? TKSETSHL : TKSHL);
       RET(c);
@@ -458,9 +500,14 @@ Begin:
       if (match(lx, '|')) RET(TKLOGIOR);
       if (match(lx, '=')) RET(TKSETIOR);
       RET(c);
-   case '\'':
    case '"':
-      readstrchrlit(lx, tk, c);
+      if (lexingheadername) {
+         readheadername(lx, tk, '"');
+         lexingheadername = 0;
+      } else {
+   case '\'':
+         readstrchrlit(lx, tk, c);
+      }
       goto End;
    case '.':
       if (peek(lx, 0) == '.' && peek(lx, 1) == '.') {
@@ -903,6 +950,45 @@ ppelse(struct lexer *lx, const struct span *span)
    cnd->elsep = 1;
 }
 
+static int includedepth;
+enum { MAXINCLUDE = 200 };
+
+static void
+ppinclude(struct lexer *lx, const struct span *span0)
+{
+   char path[4096];
+   struct lexer new;
+   struct token tk;
+   struct span span = *span0;
+
+   lexingheadername = 1;
+   if (in_range(lex0(lx, &tk), TKPPHDRH, TKPPHDRQ)) {
+      const char *base, *end;
+
+      /* build relative path */
+      base = getfilename(lx->fileid);
+      for (end = base; *end != 0; ++end) {}
+      for (--end; *end != '/' && end != base; --end) {}
+      if (*end == '/') ++end;
+      memcpy(path, base, end - base);
+      memcpy(path + (end - base), tk.s, tk.len);
+      path[end - base + tk.len] = 0;
+   } else {
+      error(&tk.span, "garbage after #include");
+      ppskipline(lx);
+      return;
+   }
+   //efmt(">include %'s\n", path);
+   joinspan(&span.ex, tk.span.ex);
+   initlexer(&new, &span, path, lx->tmparena);
+   new.save = xcalloc(sizeof *new.save);
+   memcpy(new.save, lx, sizeof *lx);
+   *lx = new;
+
+   if (++includedepth == MAXINCLUDE)
+      fatal(&span, "Maximum nested include depth of %d reached", includedepth);
+}
+
 static struct macrostack mstk[64], *mfreelist;
 static bool
 tryexpand(struct lexer *lx, const struct token *tk)
@@ -1056,6 +1142,7 @@ lex(struct lexer *lx, struct token *tk_)
                case PPELIF:   ppelif(lx, &tk->span); break;
                case PPENDIF:  ppendif(lx, &tk->span); break;
                case PPELSE:   ppelse(lx, &tk->span); break;
+               case PPINCLUDE: ppinclude(lx, &tk->span); break;
                default: assert(0&&"nyi");
                }
             } else {
@@ -1090,7 +1177,15 @@ lex(struct lexer *lx, struct token *tk_)
             struct span span = { ppcndstk[nppcnd-1].ifspan };
             error(&span, "#if is not matched by #endif");
          }
-         return t;
+         if (t == TKEOF && lx->save) {
+            /* end of #include'd file, restore previous state */
+            struct lexer *sv = lx->save;
+            memcpy(lx, lx->save, sizeof *lx);
+            free(sv);
+            --includedepth;
+         } else {
+            return t;
+         }
       }
    }
    assert(0);
@@ -1113,7 +1208,7 @@ lexpeek(struct lexer *lx, struct token *tk_)
 }
 
 void
-initlexer(struct lexer *lx, const char *file, struct arena **tmparena)
+initlexer(struct lexer *lx, const struct span *span, const char *file, struct arena **tmparena)
 {
    const char *error;
    struct memfile *f;
@@ -1121,7 +1216,7 @@ initlexer(struct lexer *lx, const char *file, struct arena **tmparena)
    memset(lx, 0, sizeof *lx);
    lx->fileid = openfile(&error, &f, file);
    if (lx->fileid < 0)
-      fatal(NULL, "Cannot open %'s: %s", file, error);
+      fatal(span, "Cannot open %'s: %s", file, error);
    lx->dat = f->p;
    lx->ndat = f->n;
    lx->tmparena = tmparena;
diff --git a/lex.h b/lex.h
index 0c6d151..ae8eeec 100644
--- a/lex.h
+++ b/lex.h
@@ -15,6 +15,8 @@ enum toktag { /* single-character tokens' tag value is the character itself */
    TKNUMLIT,
    TKCHRLIT,
    TKSTRLIT,
+   TKPPHDRH, /* <hdr> (for #include) */
+   TKPPHDRQ, /* "hdr" (for #include) */
    TKEQU = '@', /* == */
    TKNEQ, /* != */
    TKLTE, /* <= */
@@ -104,6 +106,6 @@ const char *intern(const char *);
 int lex(struct lexer *, struct token *);
 int lexpeek(struct lexer *, struct token *);
 enum typetag parsenumlit(uvlong *, double *, const struct token *, bool ispp);
-void initlexer(struct lexer *, const char *file, struct arena **);
+void initlexer(struct lexer *, const struct span *span, const char *file, struct arena **tmparena);
 
 /* vim:set ts=3 sw=3 expandtab: */
diff --git a/test/pp.c b/test/pp.c
new file mode 100644
index 0000000..0c199dc
--- /dev/null
+++ b/test/pp.c
@@ -0,0 +1,8 @@
+
+#include "pp.h"
+int
+main(void)
+{
+   hi();
+   return Foo;
+}
diff --git a/test/pp.h b/test/pp.h
new file mode 100644
index 0000000..69da492
--- /dev/null
+++ b/test/pp.h
@@ -0,0 +1,6 @@
+extern warnhere();
+#define Foo 9
+void hi() {
+   extern int printf();
+   printf("hi from header\n");
+}