hack to find first instruction for decoding the pc/line table properly.

SVN=122792

diff --git a/src/libmach_amd64/sym.c b/src/libmach_amd64/sym.c
index 22baa59b264cd94348b1e4d26b2ef62190118c30..9468e195767e60aedc91013bb71deda57d699ec0 100644 (file)
--- a/src/libmach_amd64/sym.c
+++ b/src/libmach_amd64/sym.c
@@ -83,6 +83,7 @@ static        Sym     *symbols;               /* symbol table */
 static Txtsym  *txt;                   /* Base of text symbol table */
 static uvlong  txtstart;               /* start of text segment */
 static uvlong  txtend;                 /* end of text segment */
+static uvlong  firstinstr;             /* as found from symtab; needed for amd64 */
 
 static void    cleansyms(void);
 static long    decodename(Biobuf*, Sym*);
@@ -385,6 +386,7 @@ buildtbls(void)
                return 1;
        isbuilt = 1;
                        /* allocate the tables */
+       firstinstr = 0;
        if(nglob) {
                globals = malloc(nglob*sizeof(*globals));
                if(!globals) {
@@ -428,6 +430,7 @@ buildtbls(void)
        hp = hist;
        ap = autos;
        for(p = symbols; i-- > 0; p++) {
+//print("sym %d type %c name %s value %llux\n", p-symbols, p->type, p->name, p->value);
                switch(p->type) {
                case 'D':
                case 'd':
@@ -474,6 +477,8 @@ buildtbls(void)
                        tp->locals = ap;
                        if(debug)
                                print("TEXT: %s at %llux\n", p->name, p->value);
+                       if (firstinstr == 0 || p->value < firstinstr)
+                               firstinstr = p->value;
                        if(f && !f->sym) {                      /* first  */
                                f->sym = p;
                                f->addr = p->value;
@@ -1045,6 +1050,7 @@ fileline(char *str, int n, uvlong dot)
                        bot = mid;
                else {
                        line = pc2line(dot);
+                       print("line %d\n", line);
                        if(line > 0 && fline(str, n, line, f->hist, 0) >= 0)
                                return 1;
                        break;
@@ -1269,7 +1275,10 @@ pc2line(uvlong pc)
        if(pcline == 0)
                return -1;
        currline = 0;
-       currpc = txtstart-mach->pcquant;
+       if (firstinstr != 0)
+               currpc = firstinstr-mach->pcquant;
+       else
+               currpc = txtstart-mach->pcquant;
        if(pc<currpc || pc>txtend)
                return ~0;