Address issues found in review <https://info.ravenbrook.com/mail/2018/09/13/15-44-23/0/>

Copied from Perforce
 Change: 195057

mps/code/eventpy.c

@@ -149,7 +149,7 @@ int main(int argc, char *argv[])
   EVENT_ANY_FIELDS(EVENT_FIELD)
 #undef EVENT_FIELD
   puts("')\nHeaderDesc.__doc__ = '''");
-#define EVENT_FIELD(TYPE, NAME, DOC) printf("  %s -- %s\n", #NAME, DOC);
+#define EVENT_FIELD(TYPE, NAME, DOC) printf("%s -- %s\n", #NAME, DOC);
   EVENT_ANY_FIELDS(EVENT_FIELD)
 #undef EVENT_FIELD
   puts("'''");
@@ -169,6 +169,29 @@ int main(int argc, char *argv[])
   PAD_TO(sizeof(EventAnyStruct));
   puts("'");
 
+  puts("\n# Mapping from access mode to its name.");
+  puts("ACCESS_MODE = {");
+  printf("    %u: \"READ\",\n", (unsigned)AccessREAD);
+  printf("    %u: \"WRITE\",\n", (unsigned)AccessWRITE);
+  printf("    %u: \"READ/WRITE\",\n",
+         (unsigned)BS_UNION(AccessREAD, AccessWRITE));
+  puts("}");
+
+  puts("\n# Mapping from rank to its name.");
+  puts("RANK = {");
+#define X(RANK) printf("    %u: \"%s\",\n", (unsigned)Rank ## RANK, #RANK);
+  RANK_LIST(X)
+#undef X
+  puts("}");
+
+  puts("\n# Mapping from trace start reason to its short decription.");
+  puts("TRACE_START_WHY = {");
+#define X(WHY, SHORT, LONG) \
+  printf("    %u: \"%s\",\n", (unsigned)TraceStartWhy ## WHY, SHORT);
+  TRACE_START_WHY_LIST(X)
+#undef X
+  puts("}");
+
   return 0;
 }
 

mps/code/mpm.h

@@ -379,7 +379,7 @@ extern RefSet ScanStateSummary(ScanState ss);
 extern Bool TraceIdCheck(TraceId id);
 extern Bool TraceSetCheck(TraceSet ts);
 extern Bool TraceCheck(Trace trace);
-extern Res TraceCreate(Trace *traceReturn, Arena arena, int why);
+extern Res TraceCreate(Trace *traceReturn, Arena arena, TraceStartWhy why);
 extern void TraceDestroyInit(Trace trace);
 extern void TraceDestroyFinished(Trace trace);
 
@@ -395,13 +395,13 @@ extern Rank TraceRankForAccess(Arena arena, Seg seg);
 extern void TraceSegAccess(Arena arena, Seg seg, AccessSet mode);
 
 extern void TraceAdvance(Trace trace);
-extern Res TraceStartCollectAll(Trace *traceReturn, Arena arena, int why);
+extern Res TraceStartCollectAll(Trace *traceReturn, Arena arena, TraceStartWhy why);
 extern Res TraceDescribe(Trace trace, mps_lib_FILE *stream, Count depth);
 
 /* traceanc.c -- Trace Ancillary */
 
 extern Bool TraceStartMessageCheck(TraceStartMessage message);
-extern const char *TraceStartWhyToString(int why);
+extern const char *TraceStartWhyToString(TraceStartWhy why);
 extern void TracePostStartMessage(Trace trace);
 extern Bool TraceMessageCheck(TraceMessage message);  /* trace end */
 extern void TracePostMessage(Trace trace);  /* trace end */
@@ -545,8 +545,8 @@ extern void ArenaPark(Globals globals);
 extern void ArenaPostmortem(Globals globals);
 extern void ArenaExposeRemember(Globals globals, Bool remember);
 extern void ArenaRestoreProtection(Globals globals);
-extern Res ArenaStartCollect(Globals globals, int why);
-extern Res ArenaCollect(Globals globals, int why);
+extern Res ArenaStartCollect(Globals globals, TraceStartWhy why);
+extern Res ArenaCollect(Globals globals, TraceStartWhy why);
 extern Bool ArenaBusy(Arena arena);
 extern Bool ArenaHasAddr(Arena arena, Addr addr);
 extern void ArenaChunkInsert(Arena arena, Chunk chunk);

mps/code/mpmst.h

@@ -443,7 +443,7 @@ typedef struct TraceStruct {
   Sig sig;                      /* <design/sig/> */
   TraceId ti;                   /* index into TraceSets */
   Arena arena;                  /* owning arena */
-  int why;                      /* why the trace began */
+  TraceStartWhy why;            /* why the trace began */
   ZoneSet white;                /* zones in the white set */
   ZoneSet mayMove;              /* zones containing possibly moving objs */
   TraceState state;             /* current state of trace */

mps/code/mpmtypes.h

@@ -60,6 +60,7 @@ typedef Size Epoch;                     /* design.mps.ld */
 typedef unsigned TraceId;               /* <design/trace/> */
 typedef unsigned TraceSet;              /* <design/trace/> */
 typedef unsigned TraceState;            /* <design/trace/> */
+typedef unsigned TraceStartWhy;
 typedef unsigned AccessSet;             /* <design/type/#access-set> */
 typedef unsigned Attr;                  /* <design/type/#attr> */
 typedef int RootVar;                    /* <design/type/#rootvar> */
@@ -298,13 +299,14 @@ enum {
 /* These definitions must match <code/mps.h#rank>. */
 /* This is checked by <code/mpsi.c#check>. */
 
+#define RANK_LIST(X) X(AMBIG) X(EXACT) X(FINAL) X(WEAK)
+
 enum {
-  RankMIN = 0,
-  RankAMBIG = 0,
-  RankEXACT = 1,
-  RankFINAL = 2,
-  RankWEAK = 3,
-  RankLIMIT
+#define X(RANK) Rank ## RANK,
+  RANK_LIST(X)
+#undef X
+  RankLIMIT,
+  RankMIN = 0
 };
 
 
@@ -356,16 +358,29 @@ enum {
 /* TODO: A better way for MPS extensions to extend the list of reasons
    instead of the catch-all TraceStartWhyEXTENSION. */
 
+#define TRACE_START_WHY_LIST(X)                                         \
+  X(CHAIN_GEN0CAP, "gen 0 capacity",                                    \
+    "Generation 0 of a chain has reached capacity: start a minor "      \
+    "collection.")                                                      \
+  X(DYNAMICCRITERION, "dynamic criterion",                              \
+    "Need to start full collection now, or there won't be enough "      \
+    "memory (ArenaAvail) to complete it.")                              \
+  X(OPPORTUNISM, "opportunism",                                         \
+    "Opportunism: client predicts plenty of idle time, so start full "  \
+    "collection.")                                                      \
+  X(CLIENTFULL_INCREMENTAL, "full incremental", \
+    "Client requests: start incremental full collection now.")          \
+  X(CLIENTFULL_BLOCK, "full", \
+    "Client requests: immediate full collection.")                      \
+  X(WALK, "walk", "Walking all live objects.")                          \
+  X(EXTENSION, "extension", \
+    "Extension: an MPS extension started the trace.")
+
 enum {
-  TraceStartWhyBASE = 1, /* not a reason, the base of the enum. */
-  TraceStartWhyCHAIN_GEN0CAP = TraceStartWhyBASE,  /* start minor */
-  TraceStartWhyDYNAMICCRITERION, /* start full */
-  TraceStartWhyOPPORTUNISM,      /* start full */
-  TraceStartWhyCLIENTFULL_INCREMENTAL,   /* start full */
-  TraceStartWhyCLIENTFULL_BLOCK, /* do full */
-  TraceStartWhyWALK,            /* walking references -- see walk.c */
-  TraceStartWhyEXTENSION,       /* MPS extension using traces */
-  TraceStartWhyLIMIT /* not a reason, the limit of the enum. */
+#define X(WHY, SHORT, LONG) TraceStartWhy ## WHY,
+  TRACE_START_WHY_LIST(X)
+#undef X
+  TraceStartWhyLIMIT
 };
 
 

mps/code/trace.c

@@ -648,7 +648,7 @@ static void traceCreatePoolGen(GenDesc gen)
   }
 }
 
-Res TraceCreate(Trace *traceReturn, Arena arena, int why)
+Res TraceCreate(Trace *traceReturn, Arena arena, TraceStartWhy why)
 {
   TraceId ti;
   Trace trace;
@@ -1723,7 +1723,7 @@ void TraceAdvance(Trace trace)
  * "why" is a TraceStartWhy* enum member that specifies why the
  * collection is starting. */
 
-Res TraceStartCollectAll(Trace *traceReturn, Arena arena, int why)
+Res TraceStartCollectAll(Trace *traceReturn, Arena arena, TraceStartWhy why)
 {
   Trace trace = NULL;
   Res res;

mps/code/traceanc.c

@@ -141,42 +141,21 @@ static void traceStartMessageInit(Arena arena, TraceStartMessage tsMessage)
  * why a trace started.
  */
  
-const char *TraceStartWhyToString(int why)
+const char *TraceStartWhyToString(TraceStartWhy why)
 {
   const char *r;
 
-  switch(why) {
-  case TraceStartWhyCHAIN_GEN0CAP:
-    r = "Generation 0 of a chain has reached capacity:"
-        " start a minor collection.";
-    break;
-  case TraceStartWhyDYNAMICCRITERION:
-    r = "Need to start full collection now, or there won't be enough"
-        " memory (ArenaAvail) to complete it.";
-    break;
-  case TraceStartWhyOPPORTUNISM:
-    r = "Opportunism: client predicts plenty of idle time,"
-        " so start full collection.";
-    break;
-  case TraceStartWhyCLIENTFULL_INCREMENTAL:
-    r = "Client requests: start incremental full collection now.";
-    break;
-  case TraceStartWhyCLIENTFULL_BLOCK:
-    r = "Client requests: immediate full collection.";
-    break;
-  case TraceStartWhyWALK:
-    r = "Walking all live objects.";
-    break;
-  case TraceStartWhyEXTENSION:
-    r = "Extension: an MPS extension started the trace.";
-    break;
+  switch (why) {
+#define X(WHY, SHORT, LONG) case TraceStartWhy ## WHY: r = (LONG); break;
+    TRACE_START_WHY_LIST(X)
+#undef X
   default:
     NOTREACHED;
     r = "Unknown reason (internal error).";
     break;
   }
 
-  /* Should fit in buffer without truncation; see .whybuf.len */
+  /* Must fit in buffer without truncation; see .whybuf.len */
   AVER(StringLength(r) < TRACE_START_MESSAGE_WHYBUF_LEN);
 
   return r;
@@ -193,14 +172,13 @@ const char *TraceStartWhyToString(int why)
  * necessary.
  */
 
-static void traceStartWhyToTextBuffer(char *s, size_t len, int why)
+static void traceStartWhyToTextBuffer(char *s, size_t len, TraceStartWhy why)
 {
   const char *r;
   size_t i;
 
   AVER(s);
   /* len can be anything, including 0. */
-  AVER(TraceStartWhyBASE <= why);
   AVER(why < TraceStartWhyLIMIT);
 
   r = TraceStartWhyToString(why);
@@ -654,7 +632,7 @@ void ArenaPostmortem(Globals globals)
 /* ArenaStartCollect -- start a collection of everything in the
  * arena; leave unclamped. */
 
-Res ArenaStartCollect(Globals globals, int why)
+Res ArenaStartCollect(Globals globals, TraceStartWhy why)
 {
   Arena arena;
   Res res;
@@ -677,7 +655,7 @@ failStart:
 
 /* ArenaCollect -- collect everything in arena; leave parked */
 
-Res ArenaCollect(Globals globals, int why)
+Res ArenaCollect(Globals globals, TraceStartWhy why)
 {
   Res res;