meson.build: enable to build Wasm backend

Enable to use tcg/wasm as the TCG backend for the WebAssembly (wasm64)
build.

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>

Author: ktock

include/accel/tcg/getpc.h

@@ -9,7 +9,7 @@
 #define ACCEL_TCG_GETPC_H
 
 /* GETPC is the true target of the return instruction that we'll execute.  */
-#ifdef CONFIG_TCG_INTERPRETER
+#if defined(CONFIG_TCG_INTERPRETER) || defined(EMSCRIPTEN)
 extern __thread uintptr_t tci_tb_ptr;
 # define GETPC() tci_tb_ptr
 #else

include/tcg/helper-info.h

@@ -9,7 +9,7 @@
 #ifndef TCG_HELPER_INFO_H
 #define TCG_HELPER_INFO_H
 
-#ifdef CONFIG_TCG_INTERPRETER
+#if defined(CONFIG_TCG_INTERPRETER) || defined(EMSCRIPTEN)
 #include <ffi.h>
 #endif
 #include "tcg-target-reg-bits.h"
@@ -48,7 +48,7 @@ struct TCGHelperInfo {
     const char *name;
 
     /* Used with g_once_init_enter. */
-#ifdef CONFIG_TCG_INTERPRETER
+#if defined(CONFIG_TCG_INTERPRETER) || defined(EMSCRIPTEN)
     ffi_cif *cif;
 #else
     uintptr_t init;

include/tcg/tcg.h

@@ -963,7 +963,7 @@ static inline size_t tcg_current_code_size(TCGContext *s)
 #define TB_EXIT_IDXMAX    1
 #define TB_EXIT_REQUESTED 3
 
-#ifdef CONFIG_TCG_INTERPRETER
+#if defined(CONFIG_TCG_INTERPRETER) || defined(EMSCRIPTEN)
 uintptr_t tcg_qemu_tb_exec(CPUArchState *env, const void *tb_ptr);
 #else
 typedef uintptr_t tcg_prologue_fn(CPUArchState *env, const void *tb_ptr);

meson.build

@@ -920,9 +920,9 @@ if have_tcg
     if not get_option('tcg_interpreter')
       error('Unsupported CPU @0@, try --enable-tcg-interpreter'.format(cpu))
     endif
-  elif host_arch == 'wasm32' or host_arch == 'wasm64'
+  elif host_arch == 'wasm32'
     if not get_option('tcg_interpreter')
-      error('WebAssembly host requires --enable-tcg-interpreter')
+      error('wasm32 host requires --enable-tcg-interpreter')
     endif
   elif get_option('tcg_interpreter')
     warning('Use of the TCG interpreter is not recommended on this host')
@@ -938,6 +938,8 @@ if have_tcg
     tcg_arch = 'i386'
   elif host_arch == 'ppc64'
     tcg_arch = 'ppc'
+  elif host_arch == 'wasm64'
+    tcg_arch = 'wasm'
   endif
   add_project_arguments('-iquote', meson.current_source_dir() / 'tcg' / tcg_arch,
                         language: all_languages)

tcg/meson.build

@@ -20,6 +20,11 @@ if get_option('tcg_interpreter')
                       method: 'pkg-config')
   tcg_ss.add(libffi)
   tcg_ss.add(files('tci.c'))
+elif host_os == 'emscripten'
+  libffi = dependency('libffi', version: '>=3.0', required: true,
+                      method: 'pkg-config')
+  specific_ss.add(libffi)
+  specific_ss.add(files('wasm.c'))
 endif
 
 tcg_ss.add(when: libdw, if_true: files('debuginfo.c'))

tcg/region.c

@@ -94,7 +94,7 @@ bool in_code_gen_buffer(const void *p)
     return (size_t)(p - region.start_aligned) <= region.total_size;
 }
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
 static int host_prot_read_exec(void)
 {
 #if defined(CONFIG_LINUX) && defined(HOST_AARCH64) && defined(PROT_BTI)
@@ -569,7 +569,7 @@ static int alloc_code_gen_buffer_anon(size_t size, int prot,
     return prot;
 }
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
 #ifdef CONFIG_POSIX
 #include "qemu/memfd.h"
 
@@ -667,11 +667,11 @@ static int alloc_code_gen_buffer_splitwx_vmremap(size_t size, Error **errp)
     return PROT_READ | PROT_WRITE;
 }
 #endif /* CONFIG_DARWIN */
-#endif /* CONFIG_TCG_INTERPRETER */
+#endif /* !CONFIG_TCG_INTERPRETER && !EMSCRIPTEN */
 
 static int alloc_code_gen_buffer_splitwx(size_t size, Error **errp)
 {
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
 # ifdef CONFIG_DARWIN
     return alloc_code_gen_buffer_splitwx_vmremap(size, errp);
 # endif
@@ -813,7 +813,7 @@ void tcg_region_init(size_t tb_size, int splitwx, unsigned max_threads)
      * Work with the page protections set up with the initial mapping.
      */
     need_prot = PROT_READ | PROT_WRITE;
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
     if (tcg_splitwx_diff == 0) {
         need_prot |= host_prot_read_exec();
     }

tcg/tcg.c

@@ -256,7 +256,7 @@ TCGv_env tcg_env;
 const void *tcg_code_gen_epilogue;
 uintptr_t tcg_splitwx_diff;
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
 tcg_prologue_fn *tcg_qemu_tb_exec;
 #endif
 
@@ -1443,7 +1443,7 @@ static TCGHelperInfo info_helper_st128_mmu = {
               | dh_typemask(ptr, 5)  /* uintptr_t ra */
 };
 
-#ifdef CONFIG_TCG_INTERPRETER
+#if defined(CONFIG_TCG_INTERPRETER) || defined(EMSCRIPTEN)
 static ffi_type *typecode_to_ffi(int argmask)
 {
     /*
@@ -1520,7 +1520,7 @@ static ffi_cif *init_ffi_layout(TCGHelperInfo *info)
 #else
 #define HELPER_INFO_INIT(I)      (&(I)->init)
 #define HELPER_INFO_INIT_VAL(I)  1
-#endif /* CONFIG_TCG_INTERPRETER */
+#endif /* CONFIG_TCG_INTERPRETER || EMSCRIPTEN */
 
 static inline bool arg_slot_reg_p(unsigned arg_slot)
 {
@@ -1897,7 +1897,7 @@ void tcg_prologue_init(void)
     s->code_buf = s->code_gen_ptr;
     s->data_gen_ptr = NULL;
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
     tcg_qemu_tb_exec = (tcg_prologue_fn *)tcg_splitwx_to_rx(s->code_ptr);
 #endif
 
@@ -1916,7 +1916,7 @@ void tcg_prologue_init(void)
     prologue_size = tcg_current_code_size(s);
     perf_report_prologue(s->code_gen_ptr, prologue_size);
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
     flush_idcache_range((uintptr_t)tcg_splitwx_to_rx(s->code_buf),
                         (uintptr_t)s->code_buf, prologue_size);
 #endif
@@ -1953,7 +1953,7 @@ void tcg_prologue_init(void)
         }
     }
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
     /*
      * Assert that goto_ptr is implemented completely, setting an epilogue.
      * For tci, we use NULL as the signal to return from the interpreter,
@@ -7055,7 +7055,7 @@ int tcg_gen_code(TCGContext *s, TranslationBlock *tb, uint64_t pc_start)
         return i;
     }
 
-#ifndef CONFIG_TCG_INTERPRETER
+#if !defined(CONFIG_TCG_INTERPRETER) && !defined(EMSCRIPTEN)
     /* flush instruction cache */
     flush_idcache_range((uintptr_t)tcg_splitwx_to_rx(s->code_buf),
                         (uintptr_t)s->code_buf,