[DTrace-devel] [PATCH 3/7 v2] Add support for indexed built-in variables lookup
Kris Van Hees
kris.van.hees at oracle.com
Sat May 28 05:37:01 UTC 2022
Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
bpf/get_bvar.c | 7 ++++++-
libdtrace/dt_cg.c | 1 +
libdtrace/dt_dis.c | 9 +++++----
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/bpf/get_bvar.c b/bpf/get_bvar.c
index 0da4b35a..4ff9b695 100644
--- a/bpf/get_bvar.c
+++ b/bpf/get_bvar.c
@@ -33,7 +33,7 @@ extern uint64_t BOOTTM;
-1; \
})
-noinline uint64_t dt_get_bvar(const dt_dctx_t *dctx, uint32_t id)
+noinline uint64_t dt_get_bvar(const dt_dctx_t *dctx, uint32_t id, uint32_t idx)
{
dt_mstate_t *mst = dctx->mst;
@@ -54,6 +54,11 @@ noinline uint64_t dt_get_bvar(const dt_dctx_t *dctx, uint32_t id)
case DIF_VAR_ARG6: case DIF_VAR_ARG7: case DIF_VAR_ARG8:
case DIF_VAR_ARG9:
return mst->argv[id - DIF_VAR_ARG0];
+ case DIF_VAR_ARGS:
+ if (idx >= sizeof(mst->argv) / sizeof(mst->argv[0]))
+ return error(dctx, DTRACEFLT_ILLOP, 0);
+
+ return mst->argv[idx];
case DIF_VAR_STACKDEPTH:
case DIF_VAR_USTACKDEPTH: {
uint32_t bufsiz = (uint32_t) (uint64_t) (&STKSIZ);
diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
index 50afa413..7d15849d 100644
--- a/libdtrace/dt_cg.c
+++ b/libdtrace/dt_cg.c
@@ -2232,6 +2232,7 @@ dt_cg_load_var(dt_node_t *dst, dt_irlist_t *dlp, dt_regset_t *drp)
emit(dlp, BPF_LOAD(BPF_DW, BPF_REG_1, BPF_REG_FP, DT_STK_DCTX));
emit(dlp, BPF_MOV_IMM(BPF_REG_2, idp->di_id));
+ emit(dlp, BPF_MOV_IMM(BPF_REG_3, 0));
idp = dt_dlib_get_func(yypcb->pcb_hdl, "dt_get_bvar");
assert(idp != NULL);
dt_regset_xalloc(drp, BPF_REG_0);
diff --git a/libdtrace/dt_dis.c b/libdtrace/dt_dis.c
index 58c02fd5..75438985 100644
--- a/libdtrace/dt_dis.c
+++ b/libdtrace/dt_dis.c
@@ -346,11 +346,12 @@ dt_dis_bpf_args(const dtrace_difo_t *dp, const char *fn,
{
if (strcmp(fn, "dt_get_bvar") == 0) {
/*
- * We know that the previous instruction exists and moves
- * the variable id to a register (because we wrote the code
- * generator to emit the instructions in this exact order.)
+ * We know that the previous two instructions exist and move
+ * the variable id to a register in the first instruction of
+ * that sequence (because we wrote the code generator to emit
+ * the instructions in this exact order.)
*/
- in--;
+ in -= 2;
snprintf(buf, len, "%s",
dt_dis_varname_id(dp, in->imm, DIFV_SCOPE_GLOBAL, addr));
return buf;
--
2.34.1
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