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| author | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2021-02-02 14:43:55 -0300 |
|---|---|---|
| committer | Roberto Ierusalimschy <roberto@inf.puc-rio.br> | 2021-02-02 14:43:55 -0300 |
| commit | e500892e18e994781760819e33098322728796e8 (patch) | |
| tree | 0a954761f83effd9aaf4c650e7dfe6e0564e37e7 /ldebug.c | |
| parent | 949187b049ce329c93d6639b91e244f2b208c807 (diff) | |
| download | lua-e500892e18e994781760819e33098322728796e8.tar.gz lua-e500892e18e994781760819e33098322728796e8.tar.bz2 lua-e500892e18e994781760819e33098322728796e8.zip | |
Optimization/simplification of 'getbaseline'
By producing absolute line information at regular intervals, a simple
division can compute the correct entry for a given instruction.
Diffstat (limited to 'ldebug.c')
| -rw-r--r-- | ldebug.c | 35 |
1 files changed, 15 insertions, 20 deletions
| @@ -46,10 +46,14 @@ static int currentpc (CallInfo *ci) { | |||
| 46 | 46 | ||
| 47 | /* | 47 | /* |
| 48 | ** Get a "base line" to find the line corresponding to an instruction. | 48 | ** Get a "base line" to find the line corresponding to an instruction. |
| 49 | ** For that, search the array of absolute line info for the largest saved | 49 | ** Base lines are regularly placed at MAXIWTHABS intervals, so usually |
| 50 | ** instruction smaller or equal to the wanted instruction. A special | 50 | ** an integer division gets the right place. When the source file has |
| 51 | ** case is when there is no absolute info or the instruction is before | 51 | ** large sequences of empty/comment lines, it may need extra entries, |
| 52 | ** the first absolute one. | 52 | ** so the original estimate needs a correction. |
| 53 | ** The assertion that the estimate is a lower bound for the correct base | ||
| 54 | ** is valid as long as the debug info has been generated with the same | ||
| 55 | ** value for MAXIWTHABS or smaller. (Previous releases use a little | ||
| 56 | ** smaller value.) | ||
| 53 | */ | 57 | */ |
| 54 | static int getbaseline (const Proto *f, int pc, int *basepc) { | 58 | static int getbaseline (const Proto *f, int pc, int *basepc) { |
| 55 | if (f->sizeabslineinfo == 0 || pc < f->abslineinfo[0].pc) { | 59 | if (f->sizeabslineinfo == 0 || pc < f->abslineinfo[0].pc) { |
| @@ -57,20 +61,11 @@ static int getbaseline (const Proto *f, int pc, int *basepc) { | |||
| 57 | return f->linedefined; | 61 | return f->linedefined; |
| 58 | } | 62 | } |
| 59 | else { | 63 | else { |
| 60 | unsigned int i; | 64 | int i = cast_uint(pc) / MAXIWTHABS - 1; /* get an estimate */ |
| 61 | if (pc >= f->abslineinfo[f->sizeabslineinfo - 1].pc) | 65 | /* estimate must be a lower bond of the correct base */ |
| 62 | i = f->sizeabslineinfo - 1; /* instruction is after last saved one */ | 66 | lua_assert(i < f->sizeabslineinfo && f->abslineinfo[i].pc <= pc); |
| 63 | else { /* binary search */ | 67 | while (i + 1 < f->sizeabslineinfo && pc >= f->abslineinfo[i + 1].pc) |
| 64 | unsigned int j = f->sizeabslineinfo - 1; /* pc < anchorlines[j] */ | 68 | i++; /* low estimate; adjust it */ |
| 65 | i = 0; /* abslineinfo[i] <= pc */ | ||
| 66 | while (i < j - 1) { | ||
| 67 | unsigned int m = (j + i) / 2; | ||
| 68 | if (pc >= f->abslineinfo[m].pc) | ||
| 69 | i = m; | ||
| 70 | else | ||
| 71 | j = m; | ||
| 72 | } | ||
| 73 | } | ||
| 74 | *basepc = f->abslineinfo[i].pc; | 69 | *basepc = f->abslineinfo[i].pc; |
| 75 | return f->abslineinfo[i].line; | 70 | return f->abslineinfo[i].line; |
| 76 | } | 71 | } |
| @@ -303,8 +298,8 @@ static void collectvalidlines (lua_State *L, Closure *f) { | |||
| 303 | sethvalue2s(L, L->top, t); /* push it on stack */ | 298 | sethvalue2s(L, L->top, t); /* push it on stack */ |
| 304 | api_incr_top(L); | 299 | api_incr_top(L); |
| 305 | setbtvalue(&v); /* boolean 'true' to be the value of all indices */ | 300 | setbtvalue(&v); /* boolean 'true' to be the value of all indices */ |
| 306 | for (i = 0; i < p->sizelineinfo; i++) { /* for all lines with code */ | 301 | for (i = 0; i < p->sizelineinfo; i++) { /* for all instructions */ |
| 307 | currentline = nextline(p, currentline, i); | 302 | currentline = nextline(p, currentline, i); /* get its line */ |
| 308 | luaH_setint(L, t, currentline, &v); /* table[line] = true */ | 303 | luaH_setint(L, t, currentline, &v); /* table[line] = true */ |
| 309 | } | 304 | } |
| 310 | } | 305 | } |