Merge pull request #91 from turbolent/improve-shared-memory

examples/pthreads/Makefile

@@ -0,0 +1,16 @@
+LDFLAGS += -lm -L../../wasi -lw2c2wasi -L../../futex -lw2c2futex
+CFLAGS += -O0 -g -DWASM_THREADS_PTHREADS
+W2C2 ?= ../../w2c2/w2c2
+
+pthreads: pthreads.o main.o
+ $(CC) $(CFLAGS) $^ -o pthreads $(LDFLAGS)
+
+%.c: src/%.wasm
+ $(W2C2) -g $< $@
+
+%.o: %.c
+ $(CC) -I../../w2c2 -c $(CFLAGS) $< -o $@
+
+.PHONY: clean
+clean:
+ rm -f *.o pthreads pthreads.h

examples/pthreads/main.c

@@ -0,0 +1,58 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "w2c2_base.h"
+#include "../../wasi/wasi.h"
+#include "pthreads.h"
+
+void
+trap(
+ Trap trap
+) {
+ fprintf(stderr, "TRAP: %s\n", trapDescription(trap));
+ abort();
+}
+
+
+wasmMemory*
+wasiMemory(
+ void* instance
+) {
+ return pthreads_memory((pthreadsInstance*)instance);
+}
+
+extern char** environ;
+
+wasmMemory* mem = NULL;
+
+void* resolveImport(const char* moduleName, const char* importName) {
+ if (strcmp(moduleName, "env") == 0 && strcmp(importName, "memory") == 0) {
+ return mem;
+ }
+ return NULL;
+}
+
+int main(int argc, char** argv) {
+ pthreadsInstance instance;
+
+ mem = WASM_MEMORY_ALLOCATE_SHARED(10, 20);
+
+ pthreadsInstantiate(&instance, resolveImport);
+
+ if (!wasiInit(argc, argv, environ)) {
+ fprintf(stderr, "failed to initialize WASI\n");
+ return 1;
+ }
+
+ if (!wasiFileDescriptorAdd(-1, "/", NULL)) {
+ fprintf(stderr, "failed to add preopen\n");
+ return 1;
+ }
+
+
+ pthreads__start(&instance);
+
+ pthreadsFreeInstance(&instance);
+
+ return 0;
+}

examples/pthreads/src/Makefile

@@ -0,0 +1,8 @@
+CC = ${WASI_SDK_PATH}/bin/clang
+
+pthreads.wasm: main.c
+ $(CC) --target=wasm32-wasi-threads --sysroot ${WASI_SDK_PATH}/share/wasi-sysroot -O0 -g -pthread -Wl,--import-memory,--export-memory,--max-memory=67108864 -o $@ $<
+
+.PHONY:
+clean:
+ rm pthreads.wasm

examples/pthreads/src/main.c

@@ -0,0 +1,53 @@
+#include <stdio.h>
+#include <pthread.h>
+
+#define NUM_THREADS 4
+#define NUM_ITER 10
+
+int g_count = 0;
+
+static void* thread(void *arg) {
+ printf("Entering thread\n");
+
+ for (int i = 0; i < NUM_ITER; i++) {
+ printf(
+ "Incremented counter: %d\n",
+ __atomic_add_fetch(&g_count, 1, __ATOMIC_SEQ_CST)
+ );
+ }
+
+ printf("Leaving thread\n");
+
+ return NULL;
+}
+
+int main(int argc, char **argv) {
+ pthread_t tids[NUM_THREADS];
+
+ printf("Starting threads\n");
+
+ for (int i = 0; i < NUM_THREADS; i++) {
+ if (pthread_create(&tids[i], NULL, thread, NULL) != 0) {
+ printf("Thread creation failed\n");
+ }
+ }
+
+ printf("Joining threads\n");
+
+ for (int i = 0; i < NUM_THREADS; i++) {
+ if (pthread_join(tids[i], NULL) != 0) {
+ printf("Thread join failed\n");
+ }
+ }
+
+ printf(
+ "Value of counter after update: %d (expected=%d)\n",
+ g_count,
+ NUM_THREADS * NUM_ITER
+ );
+ if (g_count != NUM_THREADS * NUM_ITER) {
+ __builtin_trap();
+ }
+
+ return 0;
+}

examples/threads/Makefile

@@ -9,7 +9,7 @@ else
 endif
 
 threads: threads.o main.o
- $(CC) $^ -o threads $(LDFLAGS)
+ $(CC) $(CFLAGS) $^ -o threads $(LDFLAGS)
 
 %.c: src/%.wasm
  $(W2C2) -g $< $@

futex/futex_test.c

@@ -56,7 +56,7 @@ testFutex(void) {
  TestThreadArg arg3;
  TestThreadArg arg4;
 
- mem = wasmMemoryAllocateShared(1, 1);
+ mem = wasmMemoryAllocate(1, 1, true);
 
  /* Three threads will wait on waitAddress1,
  * one thread will wait on waitAddress2. */

tests/main.c

@@ -117,7 +117,7 @@ void printOK(const char* description) {
 }
 
 static void initTest() {
- spectest_memory = wasmMemoryAllocate(1, 2);
+ spectest_memory = wasmMemoryAllocate(1, 2, false);
  spectest_shared_memory = WASM_MEMORY_ALLOCATE_SHARED(1, 2);
  wasmTableAllocate(&spectest_table, 10, 20);
 }

w2c2/c.c

@@ -5378,7 +5378,7 @@ wasmCWriteInitMemories(
  fputs(indentation, file);
  }
  wasmCWriteFileMemoryUse(file, module, moduleMemoryIndex, NULL, true);
- fprintf(file, " = wasmMemoryAllocate(%u, %u);\n", memory.min, memory.max);
+ fprintf(file, " = wasmMemoryAllocate(%u, %u, false);\n", memory.min, memory.max);
  }
  }
  }

w2c2/w2c2_base.h

@@ -673,9 +673,10 @@ W2C2_INLINE
 wasmMemory*
 wasmMemoryAllocate(
  const U32 initialPages,
- const U32 maxPages
+ const U32 maxPages,
+ const bool shared
 ) {
- const U32 size = initialPages * WASM_PAGE_SIZE;
+ const U32 size = (shared ? maxPages : initialPages) * WASM_PAGE_SIZE;
  wasmMemory* memory = (wasmMemory*)calloc(1, sizeof(wasmMemory));
  if (!memory) {
  abort();
@@ -684,34 +685,24 @@ wasmMemoryAllocate(
  memory->size = size;
  memory->pages = initialPages;
  memory->maxPages = maxPages;
- memory->shared = false;
+ memory->shared = shared;
  memory->futex = NULL;
  memory->futexFree = NULL;
- return memory;
-}
-
-static
-W2C2_INLINE
-wasmMemory*
-wasmMemoryAllocateShared(
- const U32 initialPages,
- const U32 maxPages
-) {
- wasmMemory* memory = wasmMemoryAllocate(initialPages, maxPages);
- memory->shared = true;
+ if (shared) {
 #ifdef WASM_MUTEX_TYPE
- if (!WASM_MUTEX_INIT(&memory->mutex)) {
- abort();
- }
+  if (!WASM_MUTEX_INIT(&memory->mutex)) {
+  abort();
+  }
 #else
- abort();
+  abort();
 #endif
+ }
  return memory;
 }
 
 #ifdef WASM_MUTEX_TYPE
 #define WASM_MEMORY_ALLOCATE_SHARED(initialPages, maxPages) \
- wasmMemoryAllocateShared(initialPages, maxPages)
+ wasmMemoryAllocate(initialPages, maxPages, true)
 #else
 #define WASM_MEMORY_ALLOCATE_SHARED(initialPages, maxPages) \
  (_Pragma ("GCC error \"Shared memory not supported. Please define a threads implementation to use (WASM_THREADS_*)\"") NULL)
@@ -748,6 +739,8 @@ wasmMemoryGrow(
  wasmMemory* memory,
  const U32 delta
 ) {
+ bool doRealloc = true;
+
  const U32 oldPages = memory->pages;
  const U32 newPages = memory->pages + delta;
 
@@ -759,19 +752,39 @@ wasmMemoryGrow(
  return (U32) -1;
  }
 
+ if (memory->shared) {
+ doRealloc = false;
+#ifdef WASM_MUTEX_TYPE
+ WASM_MUTEX_LOCK(&memory->mutex);
+#else
+ abort();
+#endif
+ }
+
  {
- const U32 oldSize = oldPages * WASM_PAGE_SIZE;
  const U32 newSize = newPages * WASM_PAGE_SIZE;
- const U32 deltaSize = delta * WASM_PAGE_SIZE;
- U8* newData = (U8*)realloc(memory->data, newSize);
- if (newData == NULL) {
- return (U32) -1;
+ if (doRealloc) {
+ const U32 oldSize = oldPages * WASM_PAGE_SIZE;
+ const U32 deltaSize = delta * WASM_PAGE_SIZE;
+ U8* newData = (U8*)realloc(memory->data, newSize);
+ if (newData == NULL) {
+ return (U32) -1;
+ }
+
+ memset(newData + oldSize, 0, deltaSize);
+ memory->data = newData;
  }
 
- memset(newData + oldSize, 0, deltaSize);
  memory->pages = newPages;
  memory->size = newSize;
- memory->data = newData;
+ }
+
+ if (memory->shared) {
+#ifdef WASM_MUTEX_TYPE
+ WASM_MUTEX_UNLOCK(&memory->mutex);
+#else
+ abort();
+#endif
  }
 
  return oldPages;