File 6032-erts-Refactor-StackTrace-to-include-max_depth.patch of Package erlang
From c2e3978c343e93e852e7535d11b67bcc96269b11 Mon Sep 17 00:00:00 2001
From: Sverker Eriksson <sverker@erlang.org>
Date: Wed, 23 Oct 2024 19:35:08 +0200
Subject: [PATCH 2/3] erts: Refactor StackTrace to include max_depth
Just to simplify.
On 64-bit sizeof(StackTrace) is unchanged due to struct padding.
---
erts/emulator/beam/beam_common.c | 30 +++++++++++++-----------------
erts/emulator/beam/bif.c | 1 +
erts/emulator/beam/erl_bif_info.c | 15 ++++++---------
erts/emulator/beam/erl_db_util.c | 15 ++++++++-------
erts/emulator/beam/error.h | 3 ++-
erts/emulator/beam/global.h | 2 +-
6 files changed, 31 insertions(+), 35 deletions(-)
diff --git a/erts/emulator/beam/beam_common.c b/erts/emulator/beam/beam_common.c
index d7e12a5fc7..cdcbb6d8dd 100644
--- a/erts/emulator/beam/beam_common.c
+++ b/erts/emulator/beam/beam_common.c
@@ -770,12 +770,13 @@ expand_error_value(Process* c_p, Uint freason, Eterm Value) {
static void
-gather_stacktrace(Process* p, struct StackTrace* s, int depth)
+gather_stacktrace(Process* p, struct StackTrace* s)
{
ErtsCodePtr prev;
Eterm *ptr;
- if (depth == 0) {
+ if (s->depth >= s->max_depth) {
+ ASSERT(s->depth == s->max_depth);
return;
}
@@ -791,7 +792,7 @@ gather_stacktrace(Process* p, struct StackTrace* s, int depth)
ASSERT(ptr >= STACK_TOP(p) && ptr <= STACK_START(p));
- while (ptr < STACK_START(p) && depth > 0) {
+ while (ptr < STACK_START(p) && s->depth < s->max_depth) {
if (is_CP(*ptr)) {
ErtsCodePtr return_address;
@@ -822,7 +823,6 @@ gather_stacktrace(Process* p, struct StackTrace* s, int depth)
#endif
s->trace[s->depth++] = adjusted_address;
- depth--;
}
ptr += CP_SIZE;
@@ -872,22 +872,19 @@ save_stacktrace(Process* c_p, ErtsCodePtr pc, Eterm* reg,
const ErtsCodeMFA *bif_mfa, Eterm args) {
struct StackTrace* s;
int sz;
- int depth = erts_backtrace_depth; /* max depth (never negative) */
+ /* Max depth (never negative), -1 as there is always a current function. */
+ const int max_depth = MAX(erts_backtrace_depth - 1, 0);
Eterm error_info = THE_NON_VALUE;
- if (depth > 0) {
- /* There will always be a current function */
- depth --;
- }
-
- /* Create a container for the exception data */
- sz = (offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * depth
+ /* Create a bignum container for the stack trace */
+ sz = (offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * max_depth
+ sizeof(Eterm) - 1) / sizeof(Eterm);
s = (struct StackTrace *) HAlloc(c_p, sz);
/* The following fields are inside the bignum */
s->header = make_pos_bignum_header(sz - 1);
s->freason = c_p->freason;
s->depth = 0;
+ s->max_depth = max_depth;
/*
* If the failure was in a BIF other than 'error/1', 'error/2',
@@ -919,9 +916,8 @@ save_stacktrace(Process* c_p, ErtsCodePtr pc, Eterm* reg,
s->current = bif_mfa;
/* Save first stack entry */
ASSERT(pc);
- if (depth > 0) {
+ if (s->depth < max_depth) {
s->trace[s->depth++] = pc;
- depth--;
}
s->pc = NULL;
@@ -1047,13 +1043,13 @@ save_stacktrace(Process* c_p, ErtsCodePtr pc, Eterm* reg,
}
/* Save the actual stack trace */
- gather_stacktrace(c_p, s, depth);
+ gather_stacktrace(c_p, s);
}
void
-erts_save_stacktrace(Process* p, struct StackTrace* s, int depth)
+erts_save_stacktrace(Process* p, struct StackTrace* s)
{
- gather_stacktrace(p, s, depth);
+ gather_stacktrace(p, s);
}
/*
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 9b3f04f436..eb39ea961a 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -1440,6 +1440,7 @@ BIF_RETTYPE raise_3(BIF_ALIST_3)
s->pc = NULL;
s->current = NULL;
s->depth = 0;
+ s->max_depth = 0;
hp += sz;
if (must_copy) {
int cnt;
diff --git a/erts/emulator/beam/erl_bif_info.c b/erts/emulator/beam/erl_bif_info.c
index d239d05e2a..c2bd395ad3 100644
--- a/erts/emulator/beam/erl_bif_info.c
+++ b/erts/emulator/beam/erl_bif_info.c
@@ -2368,7 +2368,6 @@ erts_build_stacktrace(ErtsHeapFactory* hfact, Process* rp,
{
Uint sz;
struct StackTrace* s;
- int depth;
FunctionInfo* stk;
FunctionInfo* stkp;
Uint heap_size;
@@ -2377,23 +2376,21 @@ erts_build_stacktrace(ErtsHeapFactory* hfact, Process* rp,
Eterm mfa;
Eterm res = NIL;
- depth = max_depth;
- sz = offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * depth;
+ sz = offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * max_depth;
s = (struct StackTrace *) erts_alloc(ERTS_ALC_T_TMP, sz);
s->depth = 0;
+ s->max_depth = max_depth;
s->pc = NULL;
- if (include_i && depth > 0 && rp->i) {
+ if (include_i && max_depth > 0 && rp->i) {
s->trace[s->depth++] = rp->i;
- depth--;
}
- erts_save_stacktrace(rp, s, depth);
+ erts_save_stacktrace(rp, s);
- depth = s->depth;
stk = stkp = (FunctionInfo *) erts_alloc(ERTS_ALC_T_TMP,
- depth*sizeof(FunctionInfo));
+ s->depth * sizeof(FunctionInfo));
heap_size = 3;
- for (i = 0; i < depth; i++) {
+ for (i = 0; i < s->depth; i++) {
erts_lookup_function_info(stkp, s->trace[i], 1);
if (stkp->mfa) {
heap_size += stkp->needed + 2;
diff --git a/erts/emulator/beam/erl_db_util.c b/erts/emulator/beam/erl_db_util.c
index 1c0fc44e22..cf5e96f221 100644
--- a/erts/emulator/beam/erl_db_util.c
+++ b/erts/emulator/beam/erl_db_util.c
@@ -2901,28 +2901,29 @@ restart:
Eterm mfa;
Eterm res;
struct StackTrace *s;
- int depth;
+ int max_depth;
FunctionInfo* stk;
FunctionInfo* stkp;
ASSERT(c_p == self);
- depth = unsigned_val(esp[-1]);
+ max_depth = unsigned_val(esp[-1]);
+ ASSERT(max_depth >= 0 && max_depth <= MAX_BACKTRACE_SIZE);
esp--;
- sz = offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * depth;
+ sz = offsetof(struct StackTrace, trace) + sizeof(ErtsCodePtr) * max_depth;
s = (struct StackTrace *) erts_alloc(ERTS_ALC_T_TMP, sz);
s->depth = 0;
+ s->max_depth = max_depth;
s->pc = NULL;
- erts_save_stacktrace(c_p, s, depth);
+ erts_save_stacktrace(c_p, s);
- depth = s->depth;
stk = stkp = (FunctionInfo *) erts_alloc(ERTS_ALC_T_TMP,
- depth*sizeof(FunctionInfo));
+ s->depth * sizeof(FunctionInfo));
heap_size = 0;
- for (i = 0; i < depth; i++) {
+ for (i = 0; i < s->depth; i++) {
erts_lookup_function_info(stkp, s->trace[i], 1);
if (stkp->mfa) {
heap_size += stkp->needed + 2;
diff --git a/erts/emulator/beam/error.h b/erts/emulator/beam/error.h
index e307f3ed6d..14c650811d 100644
--- a/erts/emulator/beam/error.h
+++ b/erts/emulator/beam/error.h
@@ -218,7 +218,8 @@ struct StackTrace {
Eterm freason; /* original exception reason is saved in the struct */
ErtsCodePtr pc;
const ErtsCodeMFA* current;
- int depth; /* number of saved pointers in trace[] */
+ int depth; /* number of saved pointers in trace[] */
+ int max_depth; /* capacity of trace[] */
ErtsCodePtr trace[1]; /* varying size - must be last in struct */
};
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 218aea136a..c172ac0df5 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1215,7 +1215,7 @@ void erts_prepare_bs_construct_fail_info(Process* c_p, const BeamInstr* p, Eterm
void erts_dirty_process_main(ErtsSchedulerData *);
Eterm build_stacktrace(Process* c_p, Eterm exc);
Eterm expand_error_value(Process* c_p, Uint freason, Eterm Value);
-void erts_save_stacktrace(Process* p, struct StackTrace* s, int depth);
+void erts_save_stacktrace(Process* p, struct StackTrace* s);
ErtsCodePtr erts_printable_return_address(Process* p, Eterm *E) ERTS_NOINLINE;
/* erl_init.c */
--
2.43.0
