JIT compiler update.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1672 2f5784b3-3f2a-0410-8824-cb99058d5e15

13 files changed, 199 insertions, 1 deletions

diff --git a/sljit/sljitConfig.h b/sljit/sljitConfig.h
index a548c37..eb9c608 100644
--- a/sljit/sljitConfig.h
+++ b/sljit/sljitConfig.h
@@ -90,10 +90,20 @@
 
 /* Executable code allocation:
    If SLJIT_EXECUTABLE_ALLOCATOR is not defined, the application should
-   define both SLJIT_MALLOC_EXEC and SLJIT_FREE_EXEC. */
+   define SLJIT_MALLOC_EXEC, SLJIT_FREE_EXEC, and SLJIT_ENABLE_EXEC. */
 #ifndef SLJIT_EXECUTABLE_ALLOCATOR
 /* Enabled by default. */
 #define SLJIT_EXECUTABLE_ALLOCATOR 1
+
+/* When SLJIT_PROT_EXECUTABLE_ALLOCATOR is enabled SLJIT uses
+   an allocator which does not set writable and executable
+   permission flags at the same time. The trade-of is increased
+   memory consumption and disabled dynamic code modifications. */
+#ifndef SLJIT_PROT_EXECUTABLE_ALLOCATOR
+/* Disabled by default. */
+#define SLJIT_PROT_EXECUTABLE_ALLOCATOR 0
+#endif
+
 #endif
 
 /* Force cdecl calling convention even if a better calling
diff --git a/sljit/sljitConfigInternal.h b/sljit/sljitConfigInternal.h
index 566c368..4dc452f 100644
--- a/sljit/sljitConfigInternal.h
+++ b/sljit/sljitConfigInternal.h
@@ -545,6 +545,14 @@ SLJIT_API_FUNC_ATTRIBUTE void sljit_free_exec(void* ptr);
 SLJIT_API_FUNC_ATTRIBUTE void sljit_free_unused_memory_exec(void);
 #define SLJIT_MALLOC_EXEC(size) sljit_malloc_exec(size)
 #define SLJIT_FREE_EXEC(ptr) sljit_free_exec(ptr)
+
+#if (defined SLJIT_PROT_EXECUTABLE_ALLOCATOR && SLJIT_PROT_EXECUTABLE_ALLOCATOR)
+SLJIT_API_FUNC_ATTRIBUTE void sljit_enable_exec(void* from, void *to);
+#define SLJIT_ENABLE_EXEC(from, to) sljit_enable_exec((from), (to))
+#else
+#define SLJIT_ENABLE_EXEC(from, to)
+#endif
+
 #endif
 
 /**********************************************/
diff --git a/sljit/sljitLir.c b/sljit/sljitLir.c
index ec1781e..a6ecc01 100644
--- a/sljit/sljitLir.c
+++ b/sljit/sljitLir.c
@@ -242,9 +242,15 @@
 #if !(defined SLJIT_CONFIG_UNSUPPORTED && SLJIT_CONFIG_UNSUPPORTED)
 
 #if (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR)
+
+#if (defined SLJIT_PROT_EXECUTABLE_ALLOCATOR && SLJIT_PROT_EXECUTABLE_ALLOCATOR)
+#include "sljitProtExecAllocator.c"
+#else
 #include "sljitExecAllocator.c"
 #endif
 
+#endif
+
 /* Argument checking features. */
 
 #if (defined SLJIT_ARGUMENT_CHECKS && SLJIT_ARGUMENT_CHECKS)
@@ -283,6 +289,13 @@
 		} \
 	} while (0)
 
+#define CHECK_DYN_CODE_MOD(extra_check) \
+	if ((extra_check) && !sljit_is_dyn_code_modification_enabled()) \
+	{ \
+		compiler->error = SLJIT_ERR_DYN_CODE_MOD; \
+		return NULL; \
+	}
+
 #elif (defined SLJIT_DEBUG && SLJIT_DEBUG)
 
 /* Assertion failure occures if an invalid argument is passed. */
@@ -295,6 +308,7 @@
 #define CHECK(x) x
 #define CHECK_PTR(x) x
 #define CHECK_REG_INDEX(x) x
+#define CHECK_DYN_CODE_MOD(extra_check) SLJIT_ASSERT(!(extra_check) || sljit_is_dyn_code_modification_enabled())
 
 #elif (defined SLJIT_VERBOSE && SLJIT_VERBOSE)
 
@@ -304,6 +318,7 @@
 #define CHECK(x) x
 #define CHECK_PTR(x) x
 #define CHECK_REG_INDEX(x) x
+#define CHECK_DYN_CODE_MOD(extra_check)
 
 #else
 
@@ -311,6 +326,7 @@
 #define CHECK(x)
 #define CHECK_PTR(x)
 #define CHECK_REG_INDEX(x)
+#define CHECK_DYN_CODE_MOD(extra_check)
 
 #endif /* SLJIT_ARGUMENT_CHECKS */
 
@@ -441,6 +457,15 @@ SLJIT_API_FUNC_ATTRIBUTE void sljit_set_compiler_memory_error(struct sljit_compi
 		compiler->error = SLJIT_ERR_ALLOC_FAILED;
 }
 
+SLJIT_API_FUNC_ATTRIBUTE sljit_s32 sljit_is_dyn_code_modification_enabled(void)
+{
+#if (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR) \
+		&& (defined SLJIT_PROT_EXECUTABLE_ALLOCATOR && SLJIT_PROT_EXECUTABLE_ALLOCATOR)
+	return 0;
+#endif
+	return 1;
+}
+
 #if (defined SLJIT_CONFIG_ARM_THUMB2 && SLJIT_CONFIG_ARM_THUMB2)
 SLJIT_API_FUNC_ATTRIBUTE void sljit_free_code(void* code)
 {
@@ -1601,6 +1626,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_cmp(struct sljit_compiler
 	sljit_sw tmp_srcw;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_cmp(compiler, type, src1, src1w, src2, src2w));
 
 	condition = type & 0xff;
@@ -1681,6 +1707,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_fcmp(struct sljit_compile
 	sljit_s32 flags, condition;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_fcmp(compiler, type, src1, src1w, src2, src2w));
 
 	condition = type & 0xff;
diff --git a/sljit/sljitLir.h b/sljit/sljitLir.h
index df69b86..facddb6 100644
--- a/sljit/sljitLir.h
+++ b/sljit/sljitLir.h
@@ -99,6 +99,8 @@ of sljitConfigInternal.h */
 #define SLJIT_ERR_UNSUPPORTED		4
 /* An ivalid argument is passed to any SLJIT function. */
 #define SLJIT_ERR_BAD_ARGUMENT		5
+/* Dynamic code modification is not enabled. */
+#define SLJIT_ERR_DYN_CODE_MOD		6
 
 /* --------------------------------------------------------------------- */
 /*  Registers                                                            */
@@ -455,7 +457,19 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_alloc_memory(struct sljit_compiler *compile
 SLJIT_API_FUNC_ATTRIBUTE void sljit_compiler_verbose(struct sljit_compiler *compiler, FILE* verbose);
 #endif
 
+/* Returns with non-zero if dynamic code modification is enabled. */
+
+SLJIT_API_FUNC_ATTRIBUTE sljit_s32 sljit_is_dyn_code_modification_enabled(void);
+
+/*
+   Create executable code from the sljit instruction stream. This is the final step
+   of the code generation so no more instructions can be added after this call.
+*/
+
 SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compiler);
+
+/* Free executable code. */
+
 SLJIT_API_FUNC_ATTRIBUTE void sljit_free_code(void* code);
 
 /*
diff --git a/sljit/sljitNativeARM_32.c b/sljit/sljitNativeARM_32.c
index b92808f..a756f82 100644
--- a/sljit/sljitNativeARM_32.c
+++ b/sljit/sljitNativeARM_32.c
@@ -793,6 +793,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_uw);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 	return code;
 }
@@ -2402,6 +2403,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	struct sljit_jump *jump;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump*)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -2534,6 +2536,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	sljit_s32 reg;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeARM_64.c b/sljit/sljitNativeARM_64.c
index d995851..75777a8 100644
--- a/sljit/sljitNativeARM_64.c
+++ b/sljit/sljitNativeARM_64.c
@@ -309,6 +309,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_ins);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 	return code;
 }
@@ -1882,6 +1883,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	struct sljit_jump *jump;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump*)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -2020,6 +2022,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	sljit_s32 dst_r;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeARM_T2_32.c b/sljit/sljitNativeARM_T2_32.c
index 1ed44a8..2952a3e 100644
--- a/sljit/sljitNativeARM_T2_32.c
+++ b/sljit/sljitNativeARM_T2_32.c
@@ -415,6 +415,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_u16);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 	/* Set thumb mode flag. */
 	return (void*)((sljit_uw)code | 0x1);
@@ -1917,6 +1918,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	sljit_ins cc;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump*)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -2060,6 +2062,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	sljit_s32 dst_r;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeMIPS_common.c b/sljit/sljitNativeMIPS_common.c
index c2c251b..3d58bb5 100644
--- a/sljit/sljitNativeMIPS_common.c
+++ b/sljit/sljitNativeMIPS_common.c
@@ -477,6 +477,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_ins);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 #ifndef __GNUC__
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 #else
@@ -1625,6 +1626,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	sljit_s32 delay_check = UNMOVABLE_INS;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump*)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -1742,6 +1744,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_cmp(struct sljit_compiler
 	sljit_ins inst;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_cmp(compiler, type, src1, src1w, src2, src2w));
 	ADJUST_LOCAL_OFFSET(src1, src1w);
 	ADJUST_LOCAL_OFFSET(src2, src2w);
@@ -1863,6 +1866,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_fcmp(struct sljit_compile
 	sljit_s32 if_true;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_fcmp(compiler, type, src1, src1w, src2, src2w));
 
 	compiler->cache_arg = 0;
@@ -2121,6 +2125,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	sljit_s32 reg;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativePPC_common.c b/sljit/sljitNativePPC_common.c
index a364732..8621f52 100644
--- a/sljit/sljitNativePPC_common.c
+++ b/sljit/sljitNativePPC_common.c
@@ -493,6 +493,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_ins);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 
 #if (defined SLJIT_INDIRECT_CALL && SLJIT_INDIRECT_CALL)
@@ -2138,6 +2139,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	sljit_ins bo_bi_flags;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	bo_bi_flags = get_bo_bi_flags(type & 0xff);
@@ -2362,6 +2364,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	sljit_s32 reg;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeSPARC_common.c b/sljit/sljitNativeSPARC_common.c
index f3a33a1..ba77c70 100644
--- a/sljit/sljitNativeSPARC_common.c
+++ b/sljit/sljitNativeSPARC_common.c
@@ -379,6 +379,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_ins);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 	return code;
 }
@@ -1295,6 +1296,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	struct sljit_jump *jump;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump*)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -1422,6 +1424,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 	struct sljit_const *const_;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeTILEGX_64.c b/sljit/sljitNativeTILEGX_64.c
index 462a8b9..d92b858 100644
--- a/sljit/sljitNativeTILEGX_64.c
+++ b/sljit/sljitNativeTILEGX_64.c
@@ -1113,6 +1113,7 @@ SLJIT_API_FUNC_ATTRIBUTE void * sljit_generate_code(struct sljit_compiler *compi
 
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = (code_ptr - code) * sizeof(sljit_ins);
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	SLJIT_CACHE_FLUSH(code, code_ptr);
 	return code;
 }
@@ -2412,6 +2413,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump * sljit_emit_jump(struct sljit_compil
 	flush_buffer(compiler);
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	jump = (struct sljit_jump *)ensure_abuf(compiler, sizeof(struct sljit_jump));
@@ -2510,6 +2512,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const * sljit_emit_const(struct sljit_comp
 	flush_buffer(compiler);
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitNativeX86_common.c b/sljit/sljitNativeX86_common.c
index aa5ba08..960bdc2 100644
--- a/sljit/sljitNativeX86_common.c
+++ b/sljit/sljitNativeX86_common.c
@@ -581,6 +581,7 @@ SLJIT_API_FUNC_ATTRIBUTE void* sljit_generate_code(struct sljit_compiler *compil
 	SLJIT_ASSERT(code_ptr <= code + compiler->size);
 	compiler->error = SLJIT_ERR_COMPILED;
 	compiler->executable_size = code_ptr - code;
+	SLJIT_ENABLE_EXEC(code, code_ptr);
 	return (void*)code;
 }
 
@@ -2580,6 +2581,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_jump* sljit_emit_jump(struct sljit_compile
 	struct sljit_jump *jump;
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(type & SLJIT_REWRITABLE_JUMP);
 	CHECK_PTR(check_sljit_emit_jump(compiler, type));
 
 	if (SLJIT_UNLIKELY(compiler->flags_saved)) {
@@ -2908,6 +2910,7 @@ SLJIT_API_FUNC_ATTRIBUTE struct sljit_const* sljit_emit_const(struct sljit_compi
 #endif
 
 	CHECK_ERROR_PTR();
+	CHECK_DYN_CODE_MOD(1);
 	CHECK_PTR(check_sljit_emit_const(compiler, dst, dstw, init_value));
 	ADJUST_LOCAL_OFFSET(dst, dstw);
 
diff --git a/sljit/sljitProtExecAllocator.c b/sljit/sljitProtExecAllocator.c
new file mode 100644
index 0000000..90088e2
--- /dev/null
+++ b/sljit/sljitProtExecAllocator.c
@@ -0,0 +1,113 @@
+/*
+ *    Stack-less Just-In-Time compiler
+ *
+ *    Copyright 2009-2012 Zoltan Herczeg (hzmester@freemail.hu). All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright notice, this list of
+ *      conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *      of conditions and the following disclaimer in the documentation and/or other materials
+ *      provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) AND CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE COPYRIGHT HOLDER(S) OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+   This file contains a simple executable memory allocator where the
+   allocated regions are not writable and executable in the same time.
+
+   This allocator usually uses more memory than sljitExecAllocator.
+*/
+
+#ifdef _WIN32
+
+static SLJIT_INLINE void* alloc_chunk(sljit_uw size)
+{
+	return VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
+}
+
+static SLJIT_INLINE void free_chunk(void* chunk, sljit_uw size)
+{
+	SLJIT_UNUSED_ARG(size);
+	VirtualFree(chunk, 0, MEM_RELEASE);
+}
+
+static SLJIT_INLINE void enable_exec_permission(void* chunk, sljit_uw size)
+{
+	sljit_uw *uw_ptr = (sljit_uw *)ptr;
+
+	VirtualProtect(chunk, size, PAGE_EXECUTE_READ, NULL);
+}
+
+#else
+
+static SLJIT_INLINE void* alloc_chunk(sljit_uw size)
+{
+	void* retval;
+
+#ifdef MAP_ANON
+	retval = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
+#else
+	if (dev_zero < 0) {
+		if (open_dev_zero())
+			return NULL;
+	}
+	retval = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, dev_zero, 0);
+#endif
+
+	return (retval != MAP_FAILED) ? retval : NULL;
+}
+
+static SLJIT_INLINE void free_chunk(void* chunk, sljit_uw size)
+{
+	munmap(chunk, size);
+}
+
+static SLJIT_INLINE void enable_exec_permission(void* chunk, sljit_uw size)
+{
+	sljit_uw *uw_ptr = (sljit_uw *)chunk;
+
+	mprotect(uw_ptr - 1, size + sizeof(sljit_uw), PROT_READ | PROT_EXEC);
+}
+
+#endif
+
+/* --------------------------------------------------------------------- */
+/*  Common functions                                                     */
+/* --------------------------------------------------------------------- */
+
+SLJIT_API_FUNC_ATTRIBUTE void* sljit_malloc_exec(sljit_uw size)
+{
+	sljit_uw *ptr = (sljit_uw *)alloc_chunk(size + sizeof (sljit_uw));
+
+	*ptr = size;
+	return (void*)(ptr + 1);
+}
+
+SLJIT_API_FUNC_ATTRIBUTE void sljit_free_exec(void* ptr)
+{
+	sljit_uw *uw_ptr = (sljit_uw *)ptr;
+
+	free_chunk(uw_ptr - 1, uw_ptr[-1]);
+}
+
+SLJIT_API_FUNC_ATTRIBUTE void sljit_enable_exec(void* from, void *to)
+{
+	enable_exec_permission(from, ((sljit_u8 *)to) - ((sljit_u8 *)from));
+}
+
+SLJIT_API_FUNC_ATTRIBUTE void sljit_free_unused_memory_exec(void)
+{
+}