Add a call stack simulation to help build stats.

src/spesh/stats.c

@@ -1,12 +1,82 @@
 #include "moar.h"
 
+/* Logs are linear recordings marked with frame correlation IDs. We need to
+ * simulate the call stack as part of the analysis. This models a frame on
+ * the call stack and the stack respectively. */
+typedef struct SimStackFrame {
+    /* Spesh stats for the stack frame. */
+    MVMSpeshStats *ss;
+
+    /* Correlation ID. */
+    MVMuint32 cid;
+} SimStackFrame;
+typedef struct SimStack {
+    /* Array of frames. */
+    SimStackFrame *frames;
+
+    /* Current frame index and allocated space. */
+    MVMuint32 used;
+    MVMuint32 limit;
+} SimStack;
+
 /* Gets the statistics for a static frame, creating them if needed. */
 MVMSpeshStats * stats_for(MVMThreadContext *tc, MVMStaticFrame *sf) {
     if (!sf->body.spesh_stats)
         sf->body.spesh_stats = MVM_calloc(1, sizeof(MVMSpeshStats));
     return sf->body.spesh_stats;
 }
 
+/* Initializes the stack simulation. */
+void sim_stack_init(MVMThreadContext *tc, SimStack *sims) {
+    sims->used = 0;
+    sims->limit = 32;
+    sims->frames = MVM_malloc(sims->limit * sizeof(SimStackFrame));
+}
+
+/* Pushes an entry onto the stack frame model. */
+void sim_stack_push(MVMThreadContext *tc, SimStack *sims, MVMSpeshStats *ss, MVMuint32 cid) {
+    SimStackFrame *frame;
+    if (sims->used == sims->limit) {
+        sims->limit *= 2;
+        sims->frames = MVM_realloc(sims->frames, sims->limit * sizeof(SimStackFrame));
+    }
+    frame = &(sims->frames[sims->used++]);
+    frame->ss = ss;
+    frame->cid = cid;
+    printf("push %d\n", cid);
+}
+
+/* Pops the top frame from the sim stack. */
+void sim_stack_pop(MVMThreadContext *tc, SimStack *sims) {
+    if (sims->used == 0)
+        MVM_panic(1, "Spesh stats: cannot pop an empty simulation stack");
+    sims->used--;
+    printf("pop %d\n", sims->frames[sims->used].cid);
+}
+
+/* Gets the simulation stack frame for the specified correlation ID. If it is
+ * not on the top, searches to see if it's further down. If it is, then pops
+ * off the top to reach it. If it's not found at all, returns NULL and does
+ * nothing to the simulation stack. */
+SimStackFrame * sim_stack_find(MVMThreadContext *tc, SimStack *sims, MVMuint32 cid) {
+    MVMuint32 found_at = sims->used;
+    while (found_at != 0) {
+        found_at--;
+        if (sims->frames[found_at].cid == cid) {
+            MVMint32 i;
+            for (i = found_at + 1; found_at < sims->used; i++)
+                sim_stack_pop(tc, sims);
+            return &(sims->frames[found_at]);
+        }
+    }
+    return NULL;
+}
+
+/* Destroys the stack simulation. */
+void sim_stack_destroy(MVMThreadContext *tc, SimStack *sims) {
+    MVM_free(sims->frames);
+}
+
 /* Gets the stats by callsite, adding it if it's missing. */
 MVMuint32 by_callsite_idx(MVMThreadContext *tc, MVMSpeshStats *ss, MVMCallsite *cs) {
     /* See if we already have it. */
@@ -31,6 +101,8 @@ MVMuint32 by_callsite_idx(MVMThreadContext *tc, MVMSpeshStats *ss, MVMCallsite *
 void MVM_spesh_stats_update(MVMThreadContext *tc, MVMSpeshLog *sl, MVMObject *sf_updated) {
     MVMuint32 i;
     MVMuint32 n = sl->body.used;
+    SimStack sims;
+    sim_stack_init(tc, &sims);
     for (i = 0; i < n; i++) {
         MVMSpeshLogEntry *e = &(sl->body.entries[i]);
         switch (e->kind) {
@@ -44,10 +116,34 @@ void MVM_spesh_stats_update(MVMThreadContext *tc, MVMSpeshLog *sl, MVMObject *sf
                 ss->hits++;
                 callsite_idx = by_callsite_idx(tc, ss, e->entry.cs);
                 ss->by_callsite[callsite_idx].hits++;
+                sim_stack_push(tc, &sims, ss, e->id);
+                break;
+            }
+            case MVM_SPESH_LOG_PARAMETER: {
+                SimStackFrame *simf = sim_stack_find(tc, &sims, e->id);
+                /* TODO Add to parameters logging */
+                break;
+            }
+            case MVM_SPESH_LOG_PARAMETER_DECONT: {
+                SimStackFrame *simf = sim_stack_find(tc, &sims, e->id);
+                /* TODO Add to parameters logging */
+                break;
+            }
+            case MVM_SPESH_LOG_TYPE:
+            case MVM_SPESH_LOG_INVOKE:
+            case MVM_SPESH_LOG_OSR: {
+                SimStackFrame *simf = sim_stack_find(tc, &sims, e->id);
+                /* TODO Stash entry for later association */
+                break;
+            }
+            case MVM_SPESH_LOG_STATIC: {
+                SimStackFrame *simf = sim_stack_find(tc, &sims, e->id);
+                /* TODO Log static value */
                 break;
             }
         }
     }
+    sim_stack_destroy(tc, &sims);
 }
 
 void MVM_spesh_stats_gc_mark(MVMThreadContext *tc, MVMSpeshStats *ss, MVMGCWorklist *worklist) {