Improve Windows build support.

- Use multithreading (works with a sufficiently recent version of
  the Microsoft developer tools / C SDK).
- Detect CPU architecture and use AVX2 or NEON when appropriate.
- Automatically detect python installation path.

8 files changed, 112 insertions, 68 deletions

diff --git a/README.md b/README.md
index 338a280..64871b5 100644
--- a/README.md
+++ b/README.md
@@ -64,9 +64,9 @@ can be used to build the basic shell, while
 Builds and runs the unit tests. See `build.bat help` for a list of
 all available options.
 
-Note: At the moment certain optimizations, such as multithreading and
-advanced CPU instructions, are not supported on Windows.
-Work is ongoing to improve Windows support.
+Note: The build script for Windows does not support all the options
+available with build.sh. If you want to tune the build options, you'll
+have to manually edit the build script.
 
 ## Running tests
 
diff --git a/build.bat b/build.bat
index 909ff01..9f9f5f1 100644
--- a/build.bat
+++ b/build.bat
@@ -9,15 +9,25 @@ if [%1]==[/d] (
 

 SET CC=clang

 SET CXX=clang++

-SET ARCH=PORTABLE

-SET THREADS=1

+SET THREADS=16

 SET SANITIZE=

 

-:: TODO depends on ARCH variable

-SET ARCHOPTS=

-:: TODO depends on SANITIZE variable

-SET DFLAGS=-g3 -DDEBUG

+SET ARCH=PORTABLE

+clang -march=native -dM -E - < NUL | findstr /C:"__AVX2__" >NUL 2>&1

+if %ERRORLEVEL% EQU 0 (

+    SET ARCH=AVX2

+    SET ARCHOPTS=-mavx2

+    goto :ArchDone

+)

+clang -march=native -dM -E - < NUL | findstr /C:"__ARM_NEON" >NUL 2>&1

+if %ERRORLEVEL% EQU 0 (

+    SET ARCH=NEON

+    goto :ArchDone

+)

+:ArchDone

+

 

+SET DFLAGS=-g3 -DDEBUG

 SET WARNINGS=-Wno-deprecated-declarations

 SET VARIABLES=-DTHREADS=%THREADS% -D%ARCH%

 SET OFLAGS=-O3

@@ -28,7 +38,9 @@ SET STACKSIZE=-Wl,-stack:16777216
 SET LFLAGS=%STACKSIZE%

 

 :: Python libraries - change to match your local installation

-SET PYPATH=%userprofile%\AppData\Local\Programs\Python\Python313

+for /f "delims=" %%i in ('python -c "import sys; print(sys.base_prefix)"') do set PYPATH=%%i

+::SET PYPATH=%userprofile%\AppData\Local\Programs\Python\Python313

+

 SET PYINCLUDE=%PYPATH%\include

 SET PYLIBS=%PYPATH%\libs

 

diff --git a/src/solvers/distribution.h b/src/solvers/distribution.h
index e9302da..78b9b5e 100644
--- a/src/solvers/distribution.h
+++ b/src/solvers/distribution.h
@@ -10,13 +10,13 @@ typedef struct {
         const unsigned char *table;
 } getdistribution_data_t;
 
-STATIC void *getdistribution_runthread(void *);
+STATIC wrapthread_return_t getdistribution_runthread(void *);
 STATIC void getdistribution(const unsigned char *,
     uint64_t [static INFO_DISTRIBUTION_LEN], const tableinfo_t [static 1]);
 STATIC bool distribution_equal(const uint64_t [static INFO_DISTRIBUTION_LEN],
     const uint64_t [static INFO_DISTRIBUTION_LEN], uint8_t);
 
-STATIC void *
+STATIC wrapthread_return_t
 getdistribution_runthread(void *arg)
 {
         getdistribution_data_t *data = (getdistribution_data_t *)arg;
@@ -33,7 +33,7 @@ getdistribution_runthread(void *arg)
                 for (j = 0; j < ENTRIES_PER_BYTE(k); j++)
                         data->distr[(table[i] & (m << (j*k))) >> (j*k)]++;
 
-        return NULL;
+        return wrapthread_return_val;
 }
 
 STATIC void
@@ -60,12 +60,12 @@ getdistribution(
                         .distr = local_distr[i],
                         .table = table,
                 };
-                wrapthread_create(&thread[i], NULL,
+                wrapthread_create(&thread[i],
                     getdistribution_runthread, &targ[i]);
         }
 
         for (i = 0; i < THREADS; i++)
-                wrapthread_join(thread[i], NULL);
+                wrapthread_join(thread[i]);
 
         memset(distr, 0, INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
         for (i = 0; i < THREADS; i++)
diff --git a/src/solvers/h48/distribution_h48.h b/src/solvers/h48/distribution_h48.h
index 93a6933..80c946e 100644
--- a/src/solvers/h48/distribution_h48.h
+++ b/src/solvers/h48/distribution_h48.h
@@ -4,11 +4,11 @@ needed for H48 because of the intertwined fallback table, and it is easier
 to have some duplication than to make these functions needlessly generic.
 */
 
-STATIC void *getdistribution_h48_runthread(void *);
+STATIC wrapthread_return_t getdistribution_h48_runthread(void *);
 STATIC void getdistribution_h48(const unsigned char *,
     uint64_t [static INFO_DISTRIBUTION_LEN], const tableinfo_t [static 1]);
 
-STATIC void *
+STATIC wrapthread_return_t 
 getdistribution_h48_runthread(void *arg)
 {
         getdistribution_data_t *data = (getdistribution_data_t *)arg;
@@ -33,7 +33,7 @@ getdistribution_h48_runthread(void *arg)
                 data->distr[(t & (m << (3*k))) >> (3*k)]--;
         }
 
-        return NULL;
+        return wrapthread_return_val;
 }
 
 STATIC void
@@ -58,12 +58,12 @@ getdistribution_h48(
                         .distr = local_distr[i],
                         .table = table,
                 };
-                wrapthread_create(&thread[i], NULL,
+                wrapthread_create(&thread[i],
                     getdistribution_h48_runthread, &targ[i]);
         }
 
         for (i = 0; i < THREADS; i++)
-                wrapthread_join(thread[i], NULL);
+                wrapthread_join(thread[i]);
 
         memset(distr, 0, INFO_DISTRIBUTION_LEN * sizeof(uint64_t));
         for (i = 0; i < THREADS; i++)
diff --git a/src/solvers/h48/gendata_h48.h b/src/solvers/h48/gendata_h48.h
index ef8a854..b37bcfb 100644
--- a/src/solvers/h48/gendata_h48.h
+++ b/src/solvers/h48/gendata_h48.h
@@ -3,7 +3,7 @@ STATIC long long gendata_h48_dispatch(
 STATIC uint64_t gendata_h48short(gendata_h48short_arg_t [static 1]);
 STATIC int64_t gendata_h48(gendata_h48_arg_t [static 1]);
 STATIC void gendata_h48_maintable(gendata_h48_arg_t [static 1]);
-STATIC void *gendata_h48_runthread(void *);
+STATIC wrapthread_return_t gendata_h48_runthread(void *);
 
 STATIC_INLINE void gendata_h48_mark(gendata_h48_mark_t [static 1]);
 STATIC_INLINE bool gendata_h48_dfs_stop(
@@ -230,9 +230,9 @@ gendata_h48_maintable(gendata_h48_arg_t arg[static 1])
 
         inext = 0;
         count = 0;
-        wrapthread_mutex_init(&shortcubes_mutex, NULL);
+        wrapthread_mutex_init(&shortcubes_mutex);
         for (i = 0; i < CHUNKS; i++)
-                wrapthread_mutex_init(&table_mutex[i], NULL);
+                wrapthread_mutex_init(&table_mutex[i]);
         for (i = 0; i < THREADS; i++) {
                 dfsarg[i] = (h48_dfs_arg_t){
                         .h = arg->h,
@@ -251,7 +251,7 @@ gendata_h48_maintable(gendata_h48_arg_t arg[static 1])
                         dfsarg[i].table_mutex[ii] = &table_mutex[ii];
 
                 wrapthread_create(
-                    &thread[i], NULL, gendata_h48_runthread, &dfsarg[i]);
+                    &thread[i], gendata_h48_runthread, &dfsarg[i]);
         }
 
         if (NISSY_CANSLEEP) {
@@ -281,7 +281,7 @@ gendata_h48_maintable(gendata_h48_arg_t arg[static 1])
         }
 
         for (i = 0; i < THREADS; i++)
-                wrapthread_join(thread[i], NULL);
+                wrapthread_join(thread[i]);
 
         h48map_destroy(&shortcubes);
 
@@ -291,7 +291,7 @@ gendata_h48_maintable(gendata_h48_arg_t arg[static 1])
         writetableinfo(&arg->info, bufsize, (unsigned char *)arg->h48buf);
 }
 
-STATIC void *
+STATIC wrapthread_return_t 
 gendata_h48_runthread(void *arg)
 {
         uint64_t coord, coordext, coordmin;
@@ -328,7 +328,7 @@ gendata_h48_runthread(void *arg)
                 }
         }
 
-        return NULL;
+        return wrapthread_return_val;
 }
 
 STATIC void
diff --git a/src/solvers/h48/solve.h b/src/solvers/h48/solve.h
index 15ac6ea..4fd0aea 100644
--- a/src/solvers/h48/solve.h
+++ b/src/solvers/h48/solve.h
@@ -78,7 +78,7 @@ STATIC_INLINE void h48_prune_restore_inverse(const h48_prune_t [static 1],
 STATIC int64_t solve_h48_maketasks(
     dfsarg_solve_h48_t [static 1], dfsarg_solve_h48_maketasks_t [static 1],
     solve_h48_task_t [static H48_STARTING_CUBES], int [static 1]);
-STATIC void *solve_h48_runthread(void *);
+STATIC wrapthread_return_t solve_h48_runthread(void *);
 STATIC int64_t solve_h48_dfs(dfsarg_solve_h48_t [static 1]);
 STATIC void solve_h48_log_solutions(solution_list_t [static 1], size_t);
 STATIC int solve_h48_compare_tasks(const void *, const void *);
@@ -383,7 +383,7 @@ solve_h48_dfs(dfsarg_solve_h48_t arg[static 1])
         return ret;
 }
 
-STATIC void *
+STATIC wrapthread_return_t 
 solve_h48_runthread(void *arg)
 {
         int i, j;
@@ -445,7 +445,7 @@ solve_h48_runthread(void *arg)
 
 solve_h48_runthread_end:
         dfsarg->thread_done = true;
-        return NULL;
+        return wrapthread_return_val;
 }
 
 STATIC int64_t
@@ -638,7 +638,7 @@ solve_h48(
 
         }
 
-        wrapthread_mutex_init(&solutions_mutex, NULL);
+        wrapthread_mutex_init(&solutions_mutex);
 
         mtarg = (dfsarg_solve_h48_maketasks_t) {
                 .cube = oc.cube,
@@ -689,7 +689,7 @@ solve_h48(
                         arg[i].target_depth = d;
                         arg[i].thread_done = false;
                         wrapthread_create(
-                            &thread[i], NULL, solve_h48_runthread, &arg[i]);
+                            &thread[i], solve_h48_runthread, &arg[i]);
                 }
 
                 /* Log solutions and handle pause / stop / resume */
@@ -718,7 +718,7 @@ solve_h48(
                 }
 
                 for (i = 0; i < threads; i++)
-                        wrapthread_join(thread[i], NULL);
+                        wrapthread_join(thread[i]);
 
                 solve_h48_log_solutions(&sollist, lastused);
                 lastused = sollist.used;
diff --git a/src/utils/prefetch.h b/src/utils/prefetch.h
index 89b14e8..a2c41ef 100644
--- a/src/utils/prefetch.h
+++ b/src/utils/prefetch.h
@@ -1,15 +1,7 @@
-#if defined(AVX2)
-
-#define prefetch(a, i) _mm_prefetch(a+i, _MM_HINT_T0)
-
-#else
 #if defined(__GNUC__) || defined(__clang__)
-
-#define prefetch(a, i) __builtin_prefetch(a+i, 0, 0)
-
+    #define prefetch(a, i) __builtin_prefetch(a+i, 0, 0)
+#elif defined(AVX2)
+    #define prefetch(a, i) _mm_prefetch((char *)(a+i), _MM_HINT_T0)
 #else
-
-#define prefetch(a, i) (void)i
-
-#endif
+    #define prefetch(a, i) (void)i
 #endif
diff --git a/src/utils/wrapthread.h b/src/utils/wrapthread.h
index 28654fe..4ac72a6 100644
--- a/src/utils/wrapthread.h
+++ b/src/utils/wrapthread.h
@@ -1,37 +1,77 @@
 #if THREADS == 1
+        #define WRAPTHREAD_NOTHREADS 1
+#elif defined(__unix__)
+        #define WRAPTHREAD_PTHREADS 1
+#elif defined(__has_include)
+        #if __has_include(<pthreads.h>)
+                #define WRAPTHREAD_PTHREADS 1
+        #elif __has_include(<threads.h>)
+                #define WRAPTHREAD_C11THREADS 1
+        #endif
+#else
+        #define WRAPTHREAD_NOTHREADS 1
+#endif
+
+#if WRAPTHREAD_PTHREADS
+        #include <pthread.h>
+
+        #define wrapthread_atomic _Atomic
+
+        #define wrapthread_return_t void *
+        #define wrapthread_return_val NULL
+
+        #define wrapthread_define_var_thread_t(x) pthread_t x
+        #define wrapthread_define_var_mutex_t(x) pthread_mutex_t x
+        #define wrapthread_define_struct_thread_t(x) pthread_t x
+        #define wrapthread_define_struct_mutex_t(x) pthread_mutex_t x
+
+        #define wrapthread_define_if_threads(T, x) T x
+
+        #define wrapthread_create(a, f, arg) pthread_create(a, NULL, f, arg)
+        #define wrapthread_join(a) pthread_join(a, NULL)
+        #define wrapthread_mutex_init(a) pthread_mutex_init(a, NULL)
+        #define wrapthread_mutex_lock(a) pthread_mutex_lock(a)
+        #define wrapthread_mutex_unlock(a) pthread_mutex_unlock(a)
+
+#elif WRAPTHREAD_C11THREADS
+        #include <threads.h>
+
+        #define wrapthread_atomic _Atomic
 
-#define wrapthread_atomic
+        #define wrapthread_return_t int
+        #define wrapthread_return_val 0
 
-#define wrapthread_define_var_thread_t(x) unused char x
-#define wrapthread_define_var_mutex_t(x) unused char x
-#define wrapthread_define_struct_thread_t(x) char x
-#define wrapthread_define_struct_mutex_t(x) char x
+        #define wrapthread_define_var_thread_t(x) thrd_t x
+        #define wrapthread_define_var_mutex_t(x) mtx_t x
+        #define wrapthread_define_struct_thread_t(x) thrd_t x
+        #define wrapthread_define_struct_mutex_t(x) mtx_t x
 
-#define wrapthread_define_if_threads(T, x) T x; (void)(x)
+        #define wrapthread_define_if_threads(T, x) T x
 
-#define wrapthread_create(a, b, c, d) c(d)
-#define wrapthread_join(a, b)
-#define wrapthread_mutex_init(a, b)
-#define wrapthread_mutex_lock(a)
-#define wrapthread_mutex_unlock(a)
+        #define wrapthread_create(a, f, arg) thrd_create(a, f, arg)
+        #define wrapthread_join(a) thrd_join(a, NULL)
+        #define wrapthread_mutex_init(a) mtx_init(a, mtx_plain)
+        #define wrapthread_mutex_lock(a) mtx_lock(a)
+        #define wrapthread_mutex_unlock(a) mtx_unlock(a)
 
 #else
 
-#include <pthread.h>
+        #define wrapthread_atomic
 
-#define wrapthread_atomic _Atomic
+        #define wrapthread_return_t int
+        #define wrapthread_return_val 0
 
-#define wrapthread_define_var_thread_t(x) pthread_t x
-#define wrapthread_define_var_mutex_t(x) pthread_mutex_t x
-#define wrapthread_define_struct_thread_t(x) pthread_t x
-#define wrapthread_define_struct_mutex_t(x) pthread_mutex_t x
+        #define wrapthread_define_var_thread_t(x) unused char x
+        #define wrapthread_define_var_mutex_t(x) unused char x
+        #define wrapthread_define_struct_thread_t(x) char x
+        #define wrapthread_define_struct_mutex_t(x) char x
 
-#define wrapthread_define_if_threads(T, x) T x
+        #define wrapthread_define_if_threads(T, x) T x; (void)(x)
 
-#define wrapthread_create(a, b, c, d) pthread_create(a, b, c, d)
-#define wrapthread_join(a, b) pthread_join(a, b)
-#define wrapthread_mutex_init(a, b) pthread_mutex_init(a, b)
-#define wrapthread_mutex_lock(a) pthread_mutex_lock(a)
-#define wrapthread_mutex_unlock(a) pthread_mutex_unlock(a)
+        #define wrapthread_create(t, f, arg) f(arg)
+        #define wrapthread_join(a)
+        #define wrapthread_mutex_init(a)
+        #define wrapthread_mutex_lock(a)
+        #define wrapthread_mutex_unlock(a)
 
 #endif