wasm2c: Remove unnecessary force_read in bounds check mode for performance

src/prebuilt/wasm2c_simd_source_declarations.cc

@@ -1,22 +1,34 @@
-const char* s_simd_source_declarations = R"w2c_template(#if defined(__GNUC__) && defined(__x86_64__)
+const char* s_simd_source_declarations = R"w2c_template(#if WASM_RT_MEMCHECK_GUARD_PAGES
+)w2c_template"
+R"w2c_template(#ifdef __GNUC__
+)w2c_template"
+R"w2c_template(#if defined(__x86_64__)
 )w2c_template"
 R"w2c_template(#define SIMD_FORCE_READ(var) __asm__("" ::"x"(var));
 )w2c_template"
-R"w2c_template(#elif defined(__GNUC__) && defined(__aarch64__)
+R"w2c_template(#elif defined(__aarch64__)
 )w2c_template"
 R"w2c_template(#define SIMD_FORCE_READ(var) __asm__("" ::"w"(var));
 )w2c_template"
 R"w2c_template(#elif defined(__s390x__)
 )w2c_template"
 R"w2c_template(#define SIMD_FORCE_READ(var) __asm__("" ::"d"(var));
 )w2c_template"
-R"w2c_template(#else
+R"w2c_template(#endif
+)w2c_template"
+R"w2c_template(#endif
+)w2c_template"
+R"w2c_template(#endif
+)w2c_template"
+R"w2c_template(
+#ifndef SIMD_FORCE_READ
 )w2c_template"
 R"w2c_template(#define SIMD_FORCE_READ(var)
 )w2c_template"
 R"w2c_template(#endif
 )w2c_template"
-R"w2c_template(// TODO: equivalent constraint for ARM and other architectures
+R"w2c_template(
+// TODO: equivalent constraint for ARM and other architectures
 )w2c_template"
 R"w2c_template(
 // The below SIMD operations copy to a local variable first as the

src/prebuilt/wasm2c_source_declarations.cc

@@ -285,8 +285,36 @@ R"w2c_template(#if WASM_RT_MEMCHECK_GUARD_PAGES
 )w2c_template"
 R"w2c_template(#define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
 )w2c_template"
+R"w2c_template(
+// When using guard pages, reads have to be immediately consumed so that OOB
+)w2c_template"
+R"w2c_template(// trap checks are applied in the right place, and not optimized away.
+)w2c_template"
+R"w2c_template(#ifdef __GNUC__
+)w2c_template"
+R"w2c_template(#define FORCE_READ_INT(var) __asm__("" ::"r"(var));
+)w2c_template"
+R"w2c_template(// Clang on Mips requires "f" constraints on floats
+)w2c_template"
+R"w2c_template(// See https://github.com/llvm/llvm-project/issues/64241
+)w2c_template"
+R"w2c_template(#if defined(__clang__) && \
+)w2c_template"
+R"w2c_template(    (defined(mips) || defined(__mips__) || defined(__mips))
+)w2c_template"
+R"w2c_template(#define FORCE_READ_FLOAT(var) __asm__("" ::"f"(var));
+)w2c_template"
 R"w2c_template(#else
 )w2c_template"
+R"w2c_template(#define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
+)w2c_template"
+R"w2c_template(#endif
+)w2c_template"
+R"w2c_template(#endif
+)w2c_template"
+R"w2c_template(
+#else
+)w2c_template"
 R"w2c_template(#define MEMCHECK_DEFAULT32(mem, a, t)                \
 )w2c_template"
 R"w2c_template(  WASM_RT_CHECK_BASE(mem);                           \
@@ -307,29 +335,14 @@ R"w2c_template(  WASM_RT_CHECK_BASE(mem);          \
 R"w2c_template(  RANGE_CHECK(mem, a, sizeof(t));
 )w2c_template"
 R"w2c_template(
-#ifdef __GNUC__
-)w2c_template"
-R"w2c_template(#define FORCE_READ_INT(var) __asm__("" ::"r"(var));
-)w2c_template"
-R"w2c_template(// Clang on Mips requires "f" constraints on floats
-)w2c_template"
-R"w2c_template(// See https://github.com/llvm/llvm-project/issues/64241
-)w2c_template"
-R"w2c_template(#if defined(__clang__) && \
-)w2c_template"
-R"w2c_template(    (defined(mips) || defined(__mips__) || defined(__mips))
-)w2c_template"
-R"w2c_template(#define FORCE_READ_FLOAT(var) __asm__("" ::"f"(var));
+#ifndef FORCE_READ_INT
 )w2c_template"
-R"w2c_template(#else
-)w2c_template"
-R"w2c_template(#define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
+R"w2c_template(#define FORCE_READ_INT(var)
 )w2c_template"
 R"w2c_template(#endif
 )w2c_template"
-R"w2c_template(#else
-)w2c_template"
-R"w2c_template(#define FORCE_READ_INT(var)
+R"w2c_template(
+#ifndef FORCE_READ_FLOAT
 )w2c_template"
 R"w2c_template(#define FORCE_READ_FLOAT(var)
 )w2c_template"

src/template/wasm2c.declarations.c

@@ -151,18 +151,9 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 // or it may do a slightly faster RANGE_CHECK.
 #if WASM_RT_MEMCHECK_GUARD_PAGES
 #define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
-#else
-#define MEMCHECK_DEFAULT32(mem, a, t)                \
-  WASM_RT_CHECK_BASE(mem);                           \
-  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
-    TRAP(OOB);
-#endif
-
-// MEMCHECK_GENERAL can be used for any memory
-#define MEMCHECK_GENERAL(mem, a, t) \
-  WASM_RT_CHECK_BASE(mem);          \
-  RANGE_CHECK(mem, a, sizeof(t));
 
+// When using guard pages, reads have to be immediately consumed so that OOB
+// trap checks are applied in the right place, and not optimized away.
 #ifdef __GNUC__
 #define FORCE_READ_INT(var) __asm__("" ::"r"(var));
 // Clang on Mips requires "f" constraints on floats
@@ -173,8 +164,25 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 #else
 #define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
 #endif
+#endif
+
 #else
+#define MEMCHECK_DEFAULT32(mem, a, t)                \
+  WASM_RT_CHECK_BASE(mem);                           \
+  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
+    TRAP(OOB);
+#endif
+
+// MEMCHECK_GENERAL can be used for any memory
+#define MEMCHECK_GENERAL(mem, a, t) \
+  WASM_RT_CHECK_BASE(mem);          \
+  RANGE_CHECK(mem, a, sizeof(t));
+
+#ifndef FORCE_READ_INT
 #define FORCE_READ_INT(var)
+#endif
+
+#ifndef FORCE_READ_FLOAT
 #define FORCE_READ_FLOAT(var)
 #endif
 

src/template/wasm2c_simd.declarations.c

@@ -1,12 +1,19 @@
-#if defined(__GNUC__) && defined(__x86_64__)
+#if WASM_RT_MEMCHECK_GUARD_PAGES
+#ifdef __GNUC__
+#if defined(__x86_64__)
 #define SIMD_FORCE_READ(var) __asm__("" ::"x"(var));
-#elif defined(__GNUC__) && defined(__aarch64__)
+#elif defined(__aarch64__)
 #define SIMD_FORCE_READ(var) __asm__("" ::"w"(var));
 #elif defined(__s390x__)
 #define SIMD_FORCE_READ(var) __asm__("" ::"d"(var));
-#else
+#endif
+#endif
+#endif
+
+#ifndef SIMD_FORCE_READ
 #define SIMD_FORCE_READ(var)
 #endif
+
 // TODO: equivalent constraint for ARM and other architectures
 
 // The below SIMD operations copy to a local variable first as the

test/wasm2c/add.txt

@@ -218,18 +218,9 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 // or it may do a slightly faster RANGE_CHECK.
 #if WASM_RT_MEMCHECK_GUARD_PAGES
 #define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
-#else
-#define MEMCHECK_DEFAULT32(mem, a, t)                \
-  WASM_RT_CHECK_BASE(mem);                           \
-  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
-    TRAP(OOB);
-#endif
-
-// MEMCHECK_GENERAL can be used for any memory
-#define MEMCHECK_GENERAL(mem, a, t) \
-  WASM_RT_CHECK_BASE(mem);          \
-  RANGE_CHECK(mem, a, sizeof(t));
 
+// When using guard pages, reads have to be immediately consumed so that OOB
+// trap checks are applied in the right place, and not optimized away.
 #ifdef __GNUC__
 #define FORCE_READ_INT(var) __asm__("" ::"r"(var));
 // Clang on Mips requires "f" constraints on floats
@@ -240,8 +231,25 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 #else
 #define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
 #endif
+#endif
+
 #else
+#define MEMCHECK_DEFAULT32(mem, a, t)                \
+  WASM_RT_CHECK_BASE(mem);                           \
+  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
+    TRAP(OOB);
+#endif
+
+// MEMCHECK_GENERAL can be used for any memory
+#define MEMCHECK_GENERAL(mem, a, t) \
+  WASM_RT_CHECK_BASE(mem);          \
+  RANGE_CHECK(mem, a, sizeof(t));
+
+#ifndef FORCE_READ_INT
 #define FORCE_READ_INT(var)
+#endif
+
+#ifndef FORCE_READ_FLOAT
 #define FORCE_READ_FLOAT(var)
 #endif
 

test/wasm2c/check-imports.txt

@@ -243,18 +243,9 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 // or it may do a slightly faster RANGE_CHECK.
 #if WASM_RT_MEMCHECK_GUARD_PAGES
 #define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
-#else
-#define MEMCHECK_DEFAULT32(mem, a, t)                \
-  WASM_RT_CHECK_BASE(mem);                           \
-  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
-    TRAP(OOB);
-#endif
-
-// MEMCHECK_GENERAL can be used for any memory
-#define MEMCHECK_GENERAL(mem, a, t) \
-  WASM_RT_CHECK_BASE(mem);          \
-  RANGE_CHECK(mem, a, sizeof(t));
 
+// When using guard pages, reads have to be immediately consumed so that OOB
+// trap checks are applied in the right place, and not optimized away.
 #ifdef __GNUC__
 #define FORCE_READ_INT(var) __asm__("" ::"r"(var));
 // Clang on Mips requires "f" constraints on floats
@@ -265,8 +256,25 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 #else
 #define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
 #endif
+#endif
+
 #else
+#define MEMCHECK_DEFAULT32(mem, a, t)                \
+  WASM_RT_CHECK_BASE(mem);                           \
+  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
+    TRAP(OOB);
+#endif
+
+// MEMCHECK_GENERAL can be used for any memory
+#define MEMCHECK_GENERAL(mem, a, t) \
+  WASM_RT_CHECK_BASE(mem);          \
+  RANGE_CHECK(mem, a, sizeof(t));
+
+#ifndef FORCE_READ_INT
 #define FORCE_READ_INT(var)
+#endif
+
+#ifndef FORCE_READ_FLOAT
 #define FORCE_READ_FLOAT(var)
 #endif
 

test/wasm2c/export-names.txt

@@ -243,18 +243,9 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 // or it may do a slightly faster RANGE_CHECK.
 #if WASM_RT_MEMCHECK_GUARD_PAGES
 #define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
-#else
-#define MEMCHECK_DEFAULT32(mem, a, t)                \
-  WASM_RT_CHECK_BASE(mem);                           \
-  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
-    TRAP(OOB);
-#endif
-
-// MEMCHECK_GENERAL can be used for any memory
-#define MEMCHECK_GENERAL(mem, a, t) \
-  WASM_RT_CHECK_BASE(mem);          \
-  RANGE_CHECK(mem, a, sizeof(t));
 
+// When using guard pages, reads have to be immediately consumed so that OOB
+// trap checks are applied in the right place, and not optimized away.
 #ifdef __GNUC__
 #define FORCE_READ_INT(var) __asm__("" ::"r"(var));
 // Clang on Mips requires "f" constraints on floats
@@ -265,8 +256,25 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 #else
 #define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
 #endif
+#endif
+
 #else
+#define MEMCHECK_DEFAULT32(mem, a, t)                \
+  WASM_RT_CHECK_BASE(mem);                           \
+  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
+    TRAP(OOB);
+#endif
+
+// MEMCHECK_GENERAL can be used for any memory
+#define MEMCHECK_GENERAL(mem, a, t) \
+  WASM_RT_CHECK_BASE(mem);          \
+  RANGE_CHECK(mem, a, sizeof(t));
+
+#ifndef FORCE_READ_INT
 #define FORCE_READ_INT(var)
+#endif
+
+#ifndef FORCE_READ_FLOAT
 #define FORCE_READ_FLOAT(var)
 #endif
 

test/wasm2c/hello.txt

@@ -250,18 +250,9 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 // or it may do a slightly faster RANGE_CHECK.
 #if WASM_RT_MEMCHECK_GUARD_PAGES
 #define MEMCHECK_DEFAULT32(mem, a, t) WASM_RT_CHECK_BASE(mem);
-#else
-#define MEMCHECK_DEFAULT32(mem, a, t)                \
-  WASM_RT_CHECK_BASE(mem);                           \
-  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
-    TRAP(OOB);
-#endif
-
-// MEMCHECK_GENERAL can be used for any memory
-#define MEMCHECK_GENERAL(mem, a, t) \
-  WASM_RT_CHECK_BASE(mem);          \
-  RANGE_CHECK(mem, a, sizeof(t));
 
+// When using guard pages, reads have to be immediately consumed so that OOB
+// trap checks are applied in the right place, and not optimized away.
 #ifdef __GNUC__
 #define FORCE_READ_INT(var) __asm__("" ::"r"(var));
 // Clang on Mips requires "f" constraints on floats
@@ -272,8 +263,25 @@ static inline uint64_t checked_add_u64(uint64_t a, uint64_t b) {
 #else
 #define FORCE_READ_FLOAT(var) __asm__("" ::"r"(var));
 #endif
+#endif
+
 #else
+#define MEMCHECK_DEFAULT32(mem, a, t)                \
+  WASM_RT_CHECK_BASE(mem);                           \
+  if (UNLIKELY(a + (uint64_t)sizeof(t) > mem->size)) \
+    TRAP(OOB);
+#endif
+
+// MEMCHECK_GENERAL can be used for any memory
+#define MEMCHECK_GENERAL(mem, a, t) \
+  WASM_RT_CHECK_BASE(mem);          \
+  RANGE_CHECK(mem, a, sizeof(t));
+
+#ifndef FORCE_READ_INT
 #define FORCE_READ_INT(var)
+#endif
+
+#ifndef FORCE_READ_FLOAT
 #define FORCE_READ_FLOAT(var)
 #endif