X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FHpc.c;h=c4ff8d3be1e2d073c9b5d3b9788769208e3a5319;hp=390e03198e0d7a52718033ca98cfaee00c4f08cf;hb=a52ff7619e8b7d74a9d933d922eeea49f580bca8;hpb=53a5d0b0186379be1fb378b1ed591ff5f359178c

diff --git a/rts/Hpc.c b/rts/Hpc.c
index 390e031..c4ff8d3 100644
--- a/rts/Hpc.c
+++ b/rts/Hpc.c
@@ -2,75 +2,62 @@
  * (c)2006 Galois Connections, Inc.
  */ 
 
+#include "PosixSource.h"
+#include "Rts.h"
+
+#include "Trace.h"
+#include "Hash.h"
+#include "RtsUtils.h"
+
 #include <stdio.h>
 #include <ctype.h>
-#include <stdlib.h>
 #include <string.h>
 #include <assert.h>
-#include "HsFFI.h"
 
-#include "Rts.h"
-#include "Hpc.h"
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
 
 /* This is the runtime support for the Haskell Program Coverage (hpc) toolkit,
  * inside GHC.
  *
  */
 
-#define DEBUG_HPC 0
-#define WOP_SIZE 1024	
-
 static int hpc_inited = 0;		// Have you started this component?
-static int totalTickCount = 0;		// How many ticks have we got to work with
+static pid_t hpc_pid = 0;		// pid of this process at hpc-boot time.
+					// Only this pid will read or write .tix file(s).
 static FILE *tixFile;			// file being read/written
 static int tix_ch;			// current char
-static StgWord64 magicTixNumber;	// Magic/Hash number to mark .tix files
-
-static FILE *rixFile = NULL;		// The tracer file/pipe (to debugger)
-static FILE *rixCmdFile = NULL;		// The tracer file/pipe (from debugger)
-static StgWord64 rixCounter = 0;	// The global event counter
 
+static HashTable * moduleHash = NULL;   // module name -> HpcModuleInfo
 
-typedef enum {
-  RixThreadFinishedOp   = -1,
-  RixRaiseOp            = -2,
-  RixFinishedOp         = -3
-} HpcRixOp;
+HpcModuleInfo *modules = 0;
 
+static char *tixFilename = NULL;
 
-typedef struct _Info {
-  char *modName;		// name of module
-  int tickCount;		// number of ticks
-  int tickOffset;		// offset into a single large .tix Array
-  StgWord64 *tixArr;		// tix Array from the program execution (local for this module)
-  struct _Info *next;
-} Info;
-
-// This is a cruel hack, we should completely redesign the format specifier handling in the RTS.
-#if SIZEOF_LONG == 8
-#define PRIuWORD64 "lu"
-#else
-#define PRIuWORD64 "llu"
-#endif
-
-Info *modules = 0;
-Info *nextModule = 0;
-StgWord64 *tixBoxes = 0;	// local copy of tixBoxes array, from file.
-int totalTixes = 0;		// total number of tix boxes.
-
-static char *tixFilename;
-
-
-static void failure(char *msg) {
+static void GNU_ATTRIBUTE(__noreturn__)
+failure(char *msg) {
+  debugTrace(DEBUG_hpc,"hpc failure: %s\n",msg);
   fprintf(stderr,"Hpc failure: %s\n",msg);
-  fprintf(stderr,"(perhaps remove .tix file?)\n");
-  exit(-1);
+  if (tixFilename) {
+    fprintf(stderr,"(perhaps remove %s file?)\n",tixFilename);
+  } else {
+    fprintf(stderr,"(perhaps remove .tix file?)\n");
+  }
+  stg_exit(1);
 }
 
-
-static int init_open(char *filename) 
-{
-  tixFile = fopen(filename,"r");
+static int init_open(FILE *file) {
+  tixFile = file;
  if (tixFile == 0) {
     return 0;
   }
@@ -80,8 +67,8 @@ static int init_open(char *filename)
 
 static void expect(char c) {
   if (tix_ch != c) {
-    fprintf(stderr,"Hpc: parse failed (%c,%c)\n",tix_ch,c);
-    exit(-1);
+    fprintf(stderr,"('%c' '%c')\n",tix_ch,c);
+    failure("parse error when reading .tix file");
   }
   tix_ch = getc(tixFile);
 }
@@ -93,7 +80,7 @@ static void ws(void) {
 }
 
 static char *expectString(void) {
-  char tmp[256], *res;
+  char tmp[256], *res; // XXX
   int tmp_ix = 0;
   expect('"');
   while (tix_ch != '"') {
@@ -102,7 +89,7 @@ static char *expectString(void) {
   }
   tmp[tmp_ix++] = 0;
   expect('"');
-  res = malloc(tmp_ix);
+  res = stgMallocBytes(tmp_ix,"Hpc.expectString");
   strcpy(res,tmp);
   return res;
 }
@@ -116,56 +103,45 @@ static StgWord64 expectWord64(void) {
   return tmp;
 }
 
-static void hpc_init(void) {
-  int i;
-  Info *tmpModule;  
-
-  if (hpc_inited != 0) {
-    return;
-  }
-  hpc_inited = 1;
+static void
+readTix(void) {
+  unsigned int i;
+  HpcModuleInfo *tmpModule, *lookup;
+
+  ws();
+  expect('T');
+  expect('i');
+  expect('x');
+  ws();
+  expect('[');
+  ws();
   
-
-  tixFilename = (char *) malloc(strlen(prog_name) + 6);
-  sprintf(tixFilename, "%s.tix", prog_name);
-
-  if (init_open(tixFilename)) { 
-    totalTixes = 0;
-
-    ws();
+  while(tix_ch != ']') {
+    tmpModule = (HpcModuleInfo *)stgMallocBytes(sizeof(HpcModuleInfo),
+                                                "Hpc.readTix");
+    tmpModule->from_file = rtsTrue;
     expect('T');
     expect('i');
     expect('x');
+    expect('M');
+    expect('o');
+    expect('d');
+    expect('u');
+    expect('l');
+    expect('e');
     ws();
-    magicTixNumber = expectWord64();
+    tmpModule -> modName = expectString();
+    ws();
+    tmpModule -> hashNo = (unsigned int)expectWord64();
+    ws();
+    tmpModule -> tickCount = (int)expectWord64();
+    tmpModule -> tixArr = (StgWord64 *)calloc(tmpModule->tickCount,sizeof(StgWord64));
     ws();
     expect('[');
     ws();
-    while(tix_ch != ']') {
-      tmpModule = (Info *)calloc(1,sizeof(Info));
-      expect('(');
-      ws();
-      tmpModule -> modName = expectString();
-      ws();
-      expect(',');
-      ws();
-      tmpModule -> tickCount = (int)expectWord64();
-      ws();
-      expect(')');
+    for(i = 0;i < tmpModule->tickCount;i++) {
+      tmpModule->tixArr[i] = expectWord64();
       ws();
-      
-      tmpModule -> tickOffset = totalTixes;
-      totalTixes += tmpModule -> tickCount;
-      
-      tmpModule -> tixArr = 0;
-      
-      if (!modules) {
-	modules = tmpModule;
-      } else {
-	nextModule->next=tmpModule;
-      }
-      nextModule=tmpModule;
-      
       if (tix_ch == ',') {
 	expect(',');
 	ws();
@@ -173,419 +149,258 @@ static void hpc_init(void) {
     }
     expect(']');
     ws();
-    tixBoxes = (StgWord64 *)calloc(totalTixes,sizeof(StgWord64));
-
-    expect('[');
-    for(i = 0;i < totalTixes;i++) {
-      if (i != 0) {
-	expect(',');
-	ws();
-      }
-    tixBoxes[i] = expectWord64();
-    ws();
+    
+    lookup = lookupHashTable(moduleHash, (StgWord)tmpModule->modName);
+    if (tmpModule == NULL) {
+        debugTrace(DEBUG_hpc,"readTix: new HpcModuleInfo for %s",
+                   tmpModule->modName);
+        insertHashTable(moduleHash, (StgWord)tmpModule->modName, tmpModule);
+    } else {
+        ASSERT(lookup->tixArr != 0);
+        ASSERT(!strcmp(tmpModule->modName, lookup->modName));
+        debugTrace(DEBUG_hpc,"readTix: existing HpcModuleInfo for %s",
+                   tmpModule->modName);
+        if (tmpModule->hashNo != lookup->hashNo) {
+            fprintf(stderr,"in module '%s'\n",tmpModule->modName);
+            failure("module mismatch with .tix/.mix file hash number");
+            if (tixFilename != NULL) {
+                fprintf(stderr,"(perhaps remove %s ?)\n",tixFilename);
+            }
+            stg_exit(EXIT_FAILURE);
+        }
+        for (i=0; i < tmpModule->tickCount; i++) {
+            lookup->tixArr[i] = tmpModule->tixArr[i];
+        }
+        stgFree(tmpModule->tixArr);
+        stgFree(tmpModule->modName);
+        stgFree(tmpModule);
     }
-    expect(']');
-
-    fclose(tixFile);
-  } else {
-    // later, we will find a binary specific 
-    magicTixNumber = (StgWord64)0;
-  }
-}
 
-/* Called on a per-module basis, at startup time, declaring where the tix boxes are stored in memory.
- * This memory can be uninitized, because we will initialize it with either the contents
- * of the tix file, or all zeros.
- */
-
-int
-hs_hpc_module(char *modName,int modCount,StgWord64 *tixArr) {
-  Info *tmpModule, *lastModule;
-  int i;
-  int offset = 0;
-  
-#if DEBUG_HPC
-  fprintf(stderr,"hs_hpc_module(%s,%d)\n",modName,modCount);
-#endif
-
-  hpc_init();
-
-  tmpModule = modules;
-  lastModule = 0;
-  
-  for(;tmpModule != 0;tmpModule = tmpModule->next) {
-    if (!strcmp(tmpModule->modName,modName)) {
-      if (tmpModule->tickCount != modCount) {
-	failure("inconsistent number of tick boxes");
-      }
-      assert(tmpModule->tixArr == 0);	
-      assert(tixBoxes != 0);
-      tmpModule->tixArr = tixArr;
-      for(i=0;i < modCount;i++) {
-	tixArr[i] = tixBoxes[i + tmpModule->tickOffset];
-      }
-      return tmpModule->tickOffset;
+    if (tix_ch == ',') {
+      expect(',');
+      ws();
     }
-    lastModule = tmpModule;
-  }
-  // Did not find entry so add one on.
-  tmpModule = (Info *)calloc(1,sizeof(Info));
-  tmpModule->modName = modName;
-  tmpModule->tickCount = modCount;
-  if (lastModule) {
-    tmpModule->tickOffset = lastModule->tickOffset + lastModule->tickCount;
-  } else {
-    tmpModule->tickOffset = 0;
-  }
-  tmpModule->tixArr = tixArr;
-  for(i=0;i < modCount;i++) {
-    tixArr[i] = 0;
-  }
-  tmpModule->next = 0;
-
-  if (!modules) {
-    modules = tmpModule;
-  } else {
-    lastModule->next=tmpModule;
   }
-
-#if DEBUG_HPC
-  fprintf(stderr,"end: hs_hpc_module\n");
-#endif
-  return offset;
+  expect(']');
+  fclose(tixFile);
 }
 
-static void breakPointCommand(HpcRixOp rixOp, StgThreadID rixTid);
-
-// Breakpointing
-static StgThreadID previousTid = 0;
-static StgWord64 rixBPCounter = 0;	// The global event breakpoint counter
-static int tixBoxBP[10000];
-static int specialOpBP = 0;
-static HpcRixOp rixOpBack[WOP_SIZE];	// The actual op
-static HpcRixOp rixTidBack[WOP_SIZE];	// Tid's before the op
-
-void 
-hs_hpc_raise_event(StgTSO *current_tso) {
-  hs_hpc_tick(RixRaiseOp,current_tso);
-}
-
-void 
-hs_hpc_thread_finished_event(StgTSO *current_tso) {
-  hs_hpc_tick(RixThreadFinishedOp,current_tso);
-}
-
-/* Called on every tick, dynamically, sending to our 
- * external record of program execution.
- */
-
 void
-hs_hpc_tick(int rixOp, StgTSO *current_tso) {
-#if DEBUG_HPC
-  fprintf(stderr,"hs_hpc_tick(%x)\n",rixOp);
-#endif
-  if (rixFile == NULL) {
-    return;
-  }
-  assert(rixCmdFile != NULL);
-  StgThreadID tid = (current_tso == 0) ? 0 : current_tso->id;
+startupHpc(void)
+{
+  char *hpc_tixdir;
+  char *hpc_tixfile;
 
-  // now check to see if we have met a breakpoint condition
-  if (rixCounter == rixBPCounter || (specialOpBP && tid != previousTid)) {
-    breakPointCommand(rixOp,tid);
-  } else {
-    if (rixOp >= 0) {
-      // Tix op
-      if (tixBoxBP[rixOp] == 1) {	// reached a bp tixbox
-	  breakPointCommand(rixOp,tid);
-      }
-    } else {
-      // Special op
-      if (specialOpBP) {
-	breakPointCommand(rixOp,tid);
-      }
-    }
+  if (moduleHash == NULL) {
+      // no modules were registered with hs_hpc_module, so don't bother
+      // creating the .tix file.
+      return;
   }
-  // update the history information.
-  previousTid = tid;
-  rixOpBack[rixCounter % WOP_SIZE]  = rixOp;
-  rixTidBack[rixCounter % WOP_SIZE] = tid;
-  rixCounter++;
-
-#if DEBUG_HPC
-  fprintf(stderr,"end: hs_hpc_tick\n");
-#endif
-}
 
-static void 
-printEvent(FILE *out,StgWord64 rixCounter,StgThreadID rixTid,HpcRixOp rixOp) {
-#if DEBUG_HPC
-  if (out != stderr) {
-    printEvent(stderr,rixCounter,rixTid,rixOp);
+  if (hpc_inited != 0) {
+    return;
   }
+  hpc_inited = 1;
+  hpc_pid    = getpid();
+  hpc_tixdir = getenv("HPCTIXDIR");
+  hpc_tixfile = getenv("HPCTIXFILE");
+
+  debugTrace(DEBUG_hpc,"startupHpc");
+
+  /* XXX Check results of mallocs/strdups, and check we are requesting
+         enough bytes */
+  if (hpc_tixfile != NULL) {
+    tixFilename = strdup(hpc_tixfile);
+  } else if (hpc_tixdir != NULL) {
+    /* Make sure the directory is present;
+     * conditional code for mkdir lifted from lndir.c
+     */
+#ifdef WIN32
+    mkdir(hpc_tixdir);
+#else
+    mkdir(hpc_tixdir,0777);
 #endif
-  fprintf(out,"%" PRIuWORD64 " %u ",rixCounter,(unsigned int)rixTid);
-  switch(rixOp) {
-  case RixThreadFinishedOp:
-    fprintf(out,"ThreadFinished\n");
-  case RixRaiseOp:
-    fprintf(out,"Raise\n");
-  case RixFinishedOp:
-    fprintf(out,"Finished\n");
-  default:
-    fprintf(out,"%u\n",rixOp);
+    /* Then, try open the file
+     */
+    tixFilename = (char *) stgMallocBytes(strlen(hpc_tixdir) +
+                                          strlen(prog_name) + 12,
+                                          "Hpc.startupHpc");
+    sprintf(tixFilename,"%s/%s-%d.tix",hpc_tixdir,prog_name,(int)hpc_pid);
+  } else {
+    tixFilename = (char *) stgMallocBytes(strlen(prog_name) + 6,
+                                          "Hpc.startupHpc");
+    sprintf(tixFilename, "%s.tix", prog_name);
   }
-}
 
-static void
-breakPointCommand(HpcRixOp rixOp, StgThreadID rixTid) {
-  StgWord64 tmp64 = 0;
-  unsigned int tmp = 0;
-  printEvent(rixFile,rixCounter,rixTid,rixOp);
-  fflush(rixFile);
-  /* From here, you can ask some basic questions.
-   * 
-   *  c<nat>		set the (one) counter breakpoint
-   *  s<nat>		set the (many) tickbox breakpoint
-   *  u<nat>		unset the (many) tickbox breakpoint
-   *  x			set special bp 
-   *  o			unset special bp
-   *  h			history
-
-   * Note that you aways end up here on the first tick
-   * because the specialOpBP is equal 0.
-   */
-  int c = getc(rixCmdFile);
-  while(c != 10 && c != -1) {
-    switch(c) {
-    case 'c': // c1234	-- set counter breakpoint at 1234
-      c = getc(rixCmdFile);
-      tmp64 = 0;
-      while(isdigit(c)) {
-	tmp64 = tmp64 * 10 + (c - '0');
-	c = getc(rixCmdFile);
-      }
-#if DEBUG_HPC
-      fprintf(stderr,"setting countBP = %" PRIuWORD64 "\n",tmp64);
-#endif
-      rixBPCounter = tmp64;
-      break;
-    case 's': // s2323  -- set tick box breakpoint at 2323
-      c = getc(rixCmdFile);
-      tmp = 0;
-      while(isdigit(c)) {
-	tmp = tmp * 10 + (c - '0');
-	c = getc(rixCmdFile);
-      }
-#if DEBUG_HPC
-      fprintf(stderr,"seting bp for tix %d\n",tmp);
-#endif
-      tixBoxBP[tmp] = 1;
-      break;
-    case 'u': // u2323  -- unset tick box breakpoint at 2323
-      c = getc(rixCmdFile);
-      tmp = 0;
-      while(isdigit(c)) {
-	tmp = tmp * 10 + (c - '0');
-	c = getc(rixCmdFile);
-      }
-#if DEBUG_HPC
-      fprintf(stderr,"unseting bp for tix %d\n",tmp);
-#endif
-      tixBoxBP[tmp] = 0;
-      break;
-    case 'x': // x -- set special bp flag
-#if DEBUG_HPC
-      fprintf(stderr,"seting specialOpBP = 1\n");
-#endif
-      specialOpBP = 1;
-      c = getc(rixCmdFile);
-      break;
-    case 'o': // o -- clear special bp flag
-#if DEBUG_HPC
-      fprintf(stderr,"seting specialOpBP = 0\n");
-#endif
-      specialOpBP = 0;
-      c = getc(rixCmdFile);
-      break;
-    case 'h': // h -- history of the last few (WOP_SIZE) steps 
-      if (rixCounter > WOP_SIZE) {
-	tmp64 = rixCounter - WOP_SIZE;
-      } else {
-	tmp64 = 0;
-      }
-      for(;tmp64 < rixCounter;tmp64++) {
-	printEvent(rixFile,tmp64,rixTidBack[tmp64 % WOP_SIZE],rixOpBack[tmp64 % WOP_SIZE]);
-      }
-      fflush(rixFile);
-      c = getc(rixCmdFile);
-      break;
-    default:
-#if DEBUG_HPC
-      fprintf(stderr,"strange command from HPCRIX (%d)\n",c);
-#endif
-      c = getc(rixCmdFile);
-    }
-    while (c != 10) {          // the end of the line
-	c = getc(rixCmdFile); // to the end of the line
-    }
-    c = getc(rixCmdFile); // the first char on the next command
+  if (init_open(fopen(tixFilename,"r"))) {
+    readTix();
   }
-#if DEBUG_HPC
-  fprintf(stderr,"re entering program\n");
-#endif
 }
 
-/* This is called after all the modules have registered their local tixboxes,
- * and does a sanity check: are we good to go?
+/*
+ * Called on a per-module basis, by a constructor function compiled
+ * with each module (see Coverage.hpcInitCode), declaring where the
+ * tix boxes are stored in memory.  This memory can be uninitized,
+ * because we will initialize it with either the contents of the tix
+ * file, or all zeros.
+ *
+ * Note that we might call this before reading the .tix file, or after
+ * in the case where we loaded some Haskell code from a .so with
+ * dlopen().  So we must handle the case where we already have an
+ * HpcModuleInfo for the module which was read from the .tix file.
  */
 
 void
-startupHpc(void) {
-  Info *tmpModule;
-  char *hpcRix;
-  char *hpcRixCmd;
-#if DEBUG_HPC
-  fprintf(stderr,"startupHpc\n");
-#endif
- 
- if (hpc_inited == 0) {
-    return;
+hs_hpc_module(char *modName,
+	      StgWord32 modCount,
+	      StgWord32 modHashNo,
+              StgWord64 *tixArr)
+{
+  HpcModuleInfo *tmpModule;
+  nat i;
+
+  if (moduleHash == NULL) {
+      moduleHash = allocStrHashTable();
   }
 
-  tmpModule = modules;
+  tmpModule = lookupHashTable(moduleHash, (StgWord)modName);
+  if (tmpModule == NULL)
+  {
+      // Did not find entry so add one on.
+      tmpModule = (HpcModuleInfo *)stgMallocBytes(sizeof(HpcModuleInfo),
+                                                  "Hpc.hs_hpc_module");
+      tmpModule->modName = modName;
+      tmpModule->tickCount = modCount;
+      tmpModule->hashNo = modHashNo;
 
-  if (tixBoxes) {
-    for(;tmpModule != 0;tmpModule = tmpModule->next) {
-      totalTickCount += tmpModule->tickCount;
-      if (!tmpModule->tixArr) {
-	fprintf(stderr,"error: module %s did not register any hpc tick data\n",
-		tmpModule->modName);
-	fprintf(stderr,"(perhaps remove %s ?)\n",tixFilename);
-	exit(-1);
+      tmpModule->tixArr = tixArr;
+      for(i=0;i < modCount;i++) {
+          tixArr[i] = 0;
       }
-    }
+      tmpModule->next = modules;
+      tmpModule->from_file = rtsFalse;
+      modules = tmpModule;
+      insertHashTable(moduleHash, (StgWord)modName, tmpModule);
   }
-
-  // HPCRIX contains the name of the file to send our dynamic runtime output to (a named pipe).
-
-  hpcRix = getenv("HPCRIX");
-  if (hpcRix) {
-    int comma;
-    Info *tmpModule;  
-
-    assert(hpc_inited);
-
-    rixFile = fopen(hpcRix,"w");
-    comma = 0;
-    
-    fprintf(rixFile,"Starting %s\n",prog_name);
-    fprintf(rixFile,"[");
-    tmpModule = modules;
-    for(;tmpModule != 0;tmpModule = tmpModule->next) {
-      if (comma) {
-	fprintf(rixFile,",");
-      } else {
-	comma = 1;
+  else
+  {
+      if (tmpModule->tickCount != modCount) {
+          failure("inconsistent number of tick boxes");
+      }
+      ASSERT(tmpModule->tixArr != 0);
+      if (tmpModule->hashNo != modHashNo) {
+          fprintf(stderr,"in module '%s'\n",tmpModule->modName);
+          failure("module mismatch with .tix/.mix file hash number");
+          if (tixFilename != NULL) {
+              fprintf(stderr,"(perhaps remove %s ?)\n",tixFilename);
+          }
+          stg_exit(EXIT_FAILURE);
+      }
+      // The existing tixArr was made up when we read the .tix file,
+      // whereas this is the real tixArr, so copy the data from the
+      // .tix into the real tixArr.
+      for(i=0;i < modCount;i++) {
+          tixArr[i] = tmpModule->tixArr[i];
       }
-      fprintf(rixFile,"(\"%s\",%u)",
-	      tmpModule->modName,
-	      tmpModule->tickCount);
-#if DEBUG_HPC
-      fprintf(stderr,"(tracer)%s: %u (offset=%u)\n",
-	      tmpModule->modName,
-	      tmpModule->tickCount,
-	      tmpModule->tickOffset);
-#endif
-    }
-    fprintf(rixFile,"]\n");
-    fflush(rixFile);
-
-    // Now we open the command channel.
-    hpcRixCmd = getenv("HPCRIXCMD");
-    assert(hpcRixCmd != NULL);
-    rixCmdFile = fopen(hpcRixCmd,"r");
-    assert(rixCmdFile != NULL);
 
+      if (tmpModule->from_file) {
+          stgFree(tmpModule->modName);
+          stgFree(tmpModule->tixArr);
+      }
+      tmpModule->from_file = rtsFalse;
   }
-
 }
 
+static void
+writeTix(FILE *f) {
+  HpcModuleInfo *tmpModule;  
+  unsigned int i, inner_comma, outer_comma;
 
-/* Called at the end of execution, to write out the Hpc *.tix file  
- * for this exection. Safe to call, even if coverage is not used.
- */
-void
-exitHpc(void) {
-  Info *tmpModule;  
-  int i, comma;
+  outer_comma = 0;
 
-#if DEBUG_HPC
-  fprintf(stderr,"exitHpc\n");
-#endif
-
-  if (hpc_inited == 0) {
+  if (f == 0) {
     return;
   }
 
-  FILE *f = fopen(tixFilename,"w");
-  
-  comma = 0;
-
-  fprintf(f,"Tix %" PRIuWORD64 " [", magicTixNumber);
+  fprintf(f,"Tix [");
   tmpModule = modules;
   for(;tmpModule != 0;tmpModule = tmpModule->next) {
-    if (comma) {
+    if (outer_comma) {
       fprintf(f,",");
     } else {
-      comma = 1;
+      outer_comma = 1;
     }
-    fprintf(f,"(\"%s\",%u)",
-	   tmpModule->modName,
-	    tmpModule->tickCount);
-#if DEBUG_HPC
-    fprintf(stderr,"%s: %u (offset=%u)\n",
+    fprintf(f," TixModule \"%s\" %u %u [",
 	   tmpModule->modName,
-	   tmpModule->tickCount,
-	   tmpModule->tickOffset);
-#endif
-  }
-  fprintf(f,"] [");
-  
-  comma = 0;
-  tmpModule = modules;
-  for(;tmpModule != 0;tmpModule = tmpModule->next) {
-      if (!tmpModule->tixArr) {
-	fprintf(stderr,"warning: module %s did not register any hpc tick data\n",
-		tmpModule->modName);
-      }
-
+	    (nat)tmpModule->hashNo,
+	    (nat)tmpModule->tickCount);
+    debugTrace(DEBUG_hpc,"%s: %u (hash=%u)\n",
+	       tmpModule->modName,
+	       (nat)tmpModule->tickCount,
+               (nat)tmpModule->hashNo);
+
+    inner_comma = 0;
     for(i = 0;i < tmpModule->tickCount;i++) {
-      if (comma) {
+      if (inner_comma) {
 	fprintf(f,",");
       } else {
-	comma = 1;
+	inner_comma = 1;
       }
 
       if (tmpModule->tixArr) {
-	fprintf(f,"%" PRIuWORD64,tmpModule->tixArr[i]);
+	fprintf(f,"%" FMT_Word64,tmpModule->tixArr[i]);
       } else {
 	fprintf(f,"0");
       }
-
     }
+    fprintf(f,"]");
   }
-      
   fprintf(f,"]\n");
+  
   fclose(f);
+}
+
+static void
+freeHpcModuleInfo (HpcModuleInfo *mod)
+{
+    if (mod->from_file) {
+        stgFree(mod->modName);
+        stgFree(mod->tixArr);
+    }
+    stgFree(mod);
+}
 
-  if (rixFile != NULL) {
-    hs_hpc_tick(RixFinishedOp,(StgThreadID)0);
-    fclose(rixFile);
+/* Called at the end of execution, to write out the Hpc *.tix file
+ * for this exection. Safe to call, even if coverage is not used.
+ */
+void
+exitHpc(void) {
+  debugTrace(DEBUG_hpc,"exitHpc");
+
+  if (hpc_inited == 0) {
+    return;
   }
-  if (rixCmdFile != NULL) {
-    fclose(rixCmdFile);
+
+  // Only write the tix file if you are the original process.
+  // Any sub-process from use of fork from inside Haskell will
+  // not clober the .tix file.
+
+  if (hpc_pid == getpid()) {
+    FILE *f = fopen(tixFilename,"w");
+    writeTix(f);
   }
-  
+
+  freeHashTable(moduleHash, (void (*)(void *))freeHpcModuleInfo);
+  moduleHash = NULL;
+
+  stgFree(tixFilename);
+  tixFilename = NULL;
 }
 
+//////////////////////////////////////////////////////////////////////////////
+// This is the API into Hpc RTS from Haskell, allowing the tixs boxes
+// to be first class.
+
+HpcModuleInfo *hs_hpc_rootModule(void) {
+  return modules;
+}