Fix compiler warnings in wasm2c output (#1844)

Use stricter compiler settings and fix the resulting warnings.
This is precursor to landing windows compiler support for wasm2c.
See #1843.

7 files changed, 103 insertions, 65 deletions

diff --git a/src/c-writer.cc b/src/c-writer.cc
index 388d8168..cf0a2d71 100644
--- a/src/c-writer.cc
+++ b/src/c-writer.cc
@@ -845,10 +845,15 @@ void CWriter::WriteMultivalueTypes() {
 }
 
 void CWriter::WriteFuncTypes() {
-  Write(Newline());
-  Writef("static u32 func_types[%" PRIzd "];", module_->types.size());
-  Write(Newline(), Newline());
+  if (module_->types.size()) {
+    Writef("static u32 func_types[%" PRIzd "];", module_->types.size());
+    Write(Newline());
+  }
   Write("static void init_func_types(void) {", Newline());
+  if (!module_->types.size()) {
+    Write("}", Newline());
+    return;
+  }
   Index func_type_index = 0;
   for (TypeEntry* type : module_->types) {
     FuncType* func_type = cast<FuncType>(type);
@@ -1017,8 +1022,15 @@ void CWriter::WriteMemory(const std::string& name) {
 }
 
 void CWriter::WriteTables() {
-  if (module_->tables.size() == module_->num_table_imports)
+  if (module_->tables.size() == module_->num_table_imports) {
     return;
+  }
+
+  if (!module_->types.size()) {
+    // If no types are defined then there is no way to use the table
+    // for anything.
+    return;
+  }
 
   Write(Newline());
 
@@ -1048,17 +1060,22 @@ void CWriter::WriteDataInitializers() {
       Write(Newline());
     } else {
       for (const DataSegment* data_segment : module_->data_segments) {
-        Write(Newline(), "static const u8 data_segment_data_",
-              data_segment_index, "[] = ", OpenBrace());
-        size_t i = 0;
-        for (uint8_t x : data_segment->data) {
-          Writef("0x%02x, ", x);
-          if ((++i % 12) == 0)
+        if (!data_segment->data.size()) {
+          Write(Newline(), "static const u8* data_segment_data_",
+                data_segment_index, " = NULL;", Newline());
+        } else {
+          Write(Newline(), "static const u8 data_segment_data_",
+                data_segment_index, "[] = ", OpenBrace());
+          size_t i = 0;
+          for (uint8_t x : data_segment->data) {
+            Writef("0x%02x, ", x);
+            if ((++i % 12) == 0)
+              Write(Newline());
+          }
+          if (i > 0)
             Write(Newline());
+          Write(CloseBrace(), ";", Newline());
         }
-        if (i > 0)
-          Write(Newline());
-        Write(CloseBrace(), ";", Newline());
         ++data_segment_index;
       }
     }
@@ -1082,7 +1099,8 @@ void CWriter::WriteDataInitializers() {
     Write("LOAD_DATA(", ExternalRef(memory->name), ", ");
     WriteInitExpr(data_segment->offset);
     Write(", data_segment_data_", data_segment_index, ", ",
-          data_segment->data.size(), ");", Newline());
+          data_segment->data.size());
+    Write(");", Newline());
     ++data_segment_index;
   }
 
@@ -1090,9 +1108,18 @@ void CWriter::WriteDataInitializers() {
 }
 
 void CWriter::WriteElemInitializers() {
+  Write(Newline(), "static void init_table(void) ", OpenBrace());
+
+  if (!module_->types.size()) {
+    // If there are no types there cannot be any table entries either.
+    for (const ElemSegment* elem_segment : module_->elem_segments) {
+      assert(elem_segment->elem_exprs.size() == 0);
+    }
+    Write(CloseBrace(), Newline());
+    return;
+  }
   const Table* table = module_->tables.empty() ? nullptr : module_->tables[0];
 
-  Write(Newline(), "static void init_table(void) ", OpenBrace());
   Write("uint32_t offset;", Newline());
   if (table && module_->num_table_imports == 0) {
     uint32_t max =
diff --git a/src/prebuilt/wasm2c.include.c b/src/prebuilt/wasm2c.include.c
index a004a10e..bb23139b 100644
--- a/src/prebuilt/wasm2c.include.c
+++ b/src/prebuilt/wasm2c.include.c
@@ -87,29 +87,29 @@ const char SECTION_NAME(declarations)[] =
 "  }\n"
 "#endif\n"
 "\n"
-"DEFINE_LOAD(i32_load, u32, u32, u32);\n"
-"DEFINE_LOAD(i64_load, u64, u64, u64);\n"
-"DEFINE_LOAD(f32_load, f32, f32, f32);\n"
-"DEFINE_LOAD(f64_load, f64, f64, f64);\n"
-"DEFINE_LOAD(i32_load8_s, s8, s32, u32);\n"
-"DEFINE_LOAD(i64_load8_s, s8, s64, u64);\n"
-"DEFINE_LOAD(i32_load8_u, u8, u32, u32);\n"
-"DEFINE_LOAD(i64_load8_u, u8, u64, u64);\n"
-"DEFINE_LOAD(i32_load16_s, s16, s32, u32);\n"
-"DEFINE_LOAD(i64_load16_s, s16, s64, u64);\n"
-"DEFINE_LOAD(i32_load16_u, u16, u32, u32);\n"
-"DEFINE_LOAD(i64_load16_u, u16, u64, u64);\n"
-"DEFINE_LOAD(i64_load32_s, s32, s64, u64);\n"
-"DEFINE_LOAD(i64_load32_u, u32, u64, u64);\n"
-"DEFINE_STORE(i32_store, u32, u32);\n"
-"DEFINE_STORE(i64_store, u64, u64);\n"
-"DEFINE_STORE(f32_store, f32, f32);\n"
-"DEFINE_STORE(f64_store, f64, f64);\n"
-"DEFINE_STORE(i32_store8, u8, u32);\n"
-"DEFINE_STORE(i32_store16, u16, u32);\n"
-"DEFINE_STORE(i64_store8, u8, u64);\n"
-"DEFINE_STORE(i64_store16, u16, u64);\n"
-"DEFINE_STORE(i64_store32, u32, u64);\n"
+"DEFINE_LOAD(i32_load, u32, u32, u32)\n"
+"DEFINE_LOAD(i64_load, u64, u64, u64)\n"
+"DEFINE_LOAD(f32_load, f32, f32, f32)\n"
+"DEFINE_LOAD(f64_load, f64, f64, f64)\n"
+"DEFINE_LOAD(i32_load8_s, s8, s32, u32)\n"
+"DEFINE_LOAD(i64_load8_s, s8, s64, u64)\n"
+"DEFINE_LOAD(i32_load8_u, u8, u32, u32)\n"
+"DEFINE_LOAD(i64_load8_u, u8, u64, u64)\n"
+"DEFINE_LOAD(i32_load16_s, s16, s32, u32)\n"
+"DEFINE_LOAD(i64_load16_s, s16, s64, u64)\n"
+"DEFINE_LOAD(i32_load16_u, u16, u32, u32)\n"
+"DEFINE_LOAD(i64_load16_u, u16, u64, u64)\n"
+"DEFINE_LOAD(i64_load32_s, s32, s64, u64)\n"
+"DEFINE_LOAD(i64_load32_u, u32, u64, u64)\n"
+"DEFINE_STORE(i32_store, u32, u32)\n"
+"DEFINE_STORE(i64_store, u64, u64)\n"
+"DEFINE_STORE(f32_store, f32, f32)\n"
+"DEFINE_STORE(f64_store, f64, f64)\n"
+"DEFINE_STORE(i32_store8, u8, u32)\n"
+"DEFINE_STORE(i32_store16, u16, u32)\n"
+"DEFINE_STORE(i64_store8, u8, u64)\n"
+"DEFINE_STORE(i64_store16, u16, u64)\n"
+"DEFINE_STORE(i64_store32, u32, u64)\n"
 "\n"
 "#define I32_CLZ(x) ((x) ? __builtin_clz(x) : 32)\n"
 "#define I64_CLZ(x) ((x) ? __builtin_clzll(x) : 64)\n"
diff --git a/src/prebuilt/wasm2c.include.h b/src/prebuilt/wasm2c.include.h
index 4ba24751..97d4aea5 100644
--- a/src/prebuilt/wasm2c.include.h
+++ b/src/prebuilt/wasm2c.include.h
@@ -18,6 +18,8 @@ const char SECTION_NAME(top)[] =
 "#define WASM_RT_ADD_PREFIX(x) WASM_RT_PASTE(WASM_RT_MODULE_PREFIX, x)\n"
 "\n"
 "/* TODO(binji): only use stdint.h types in header */\n"
+"#ifndef WASM_RT_CORE_TYPES_DEFINED\n"
+"#define WASM_RT_CORE_TYPES_DEFINED\n"
 "typedef uint8_t u8;\n"
 "typedef int8_t s8;\n"
 "typedef uint16_t u16;\n"
@@ -28,6 +30,7 @@ const char SECTION_NAME(top)[] =
 "typedef int64_t s64;\n"
 "typedef float f32;\n"
 "typedef double f64;\n"
+"#endif\n"
 "\n"
 "extern void WASM_RT_ADD_PREFIX(init)(void);\n"
 ;
diff --git a/src/wasm2c.c.tmpl b/src/wasm2c.c.tmpl
index 2637ca13..f6bcc941 100644
--- a/src/wasm2c.c.tmpl
+++ b/src/wasm2c.c.tmpl
@@ -84,29 +84,29 @@ static inline void load_data(void *dest, const void *src, size_t n) {
   }
 #endif
 
-DEFINE_LOAD(i32_load, u32, u32, u32);
-DEFINE_LOAD(i64_load, u64, u64, u64);
-DEFINE_LOAD(f32_load, f32, f32, f32);
-DEFINE_LOAD(f64_load, f64, f64, f64);
-DEFINE_LOAD(i32_load8_s, s8, s32, u32);
-DEFINE_LOAD(i64_load8_s, s8, s64, u64);
-DEFINE_LOAD(i32_load8_u, u8, u32, u32);
-DEFINE_LOAD(i64_load8_u, u8, u64, u64);
-DEFINE_LOAD(i32_load16_s, s16, s32, u32);
-DEFINE_LOAD(i64_load16_s, s16, s64, u64);
-DEFINE_LOAD(i32_load16_u, u16, u32, u32);
-DEFINE_LOAD(i64_load16_u, u16, u64, u64);
-DEFINE_LOAD(i64_load32_s, s32, s64, u64);
-DEFINE_LOAD(i64_load32_u, u32, u64, u64);
-DEFINE_STORE(i32_store, u32, u32);
-DEFINE_STORE(i64_store, u64, u64);
-DEFINE_STORE(f32_store, f32, f32);
-DEFINE_STORE(f64_store, f64, f64);
-DEFINE_STORE(i32_store8, u8, u32);
-DEFINE_STORE(i32_store16, u16, u32);
-DEFINE_STORE(i64_store8, u8, u64);
-DEFINE_STORE(i64_store16, u16, u64);
-DEFINE_STORE(i64_store32, u32, u64);
+DEFINE_LOAD(i32_load, u32, u32, u32)
+DEFINE_LOAD(i64_load, u64, u64, u64)
+DEFINE_LOAD(f32_load, f32, f32, f32)
+DEFINE_LOAD(f64_load, f64, f64, f64)
+DEFINE_LOAD(i32_load8_s, s8, s32, u32)
+DEFINE_LOAD(i64_load8_s, s8, s64, u64)
+DEFINE_LOAD(i32_load8_u, u8, u32, u32)
+DEFINE_LOAD(i64_load8_u, u8, u64, u64)
+DEFINE_LOAD(i32_load16_s, s16, s32, u32)
+DEFINE_LOAD(i64_load16_s, s16, s64, u64)
+DEFINE_LOAD(i32_load16_u, u16, u32, u32)
+DEFINE_LOAD(i64_load16_u, u16, u64, u64)
+DEFINE_LOAD(i64_load32_s, s32, s64, u64)
+DEFINE_LOAD(i64_load32_u, u32, u64, u64)
+DEFINE_STORE(i32_store, u32, u32)
+DEFINE_STORE(i64_store, u64, u64)
+DEFINE_STORE(f32_store, f32, f32)
+DEFINE_STORE(f64_store, f64, f64)
+DEFINE_STORE(i32_store8, u8, u32)
+DEFINE_STORE(i32_store16, u16, u32)
+DEFINE_STORE(i64_store8, u8, u64)
+DEFINE_STORE(i64_store16, u16, u64)
+DEFINE_STORE(i64_store32, u32, u64)
 
 #define I32_CLZ(x) ((x) ? __builtin_clz(x) : 32)
 #define I64_CLZ(x) ((x) ? __builtin_clzll(x) : 64)
diff --git a/src/wasm2c.h.tmpl b/src/wasm2c.h.tmpl
index 8478d81b..2a334fd7 100644
--- a/src/wasm2c.h.tmpl
+++ b/src/wasm2c.h.tmpl
@@ -17,6 +17,8 @@ extern "C" {
 #define WASM_RT_ADD_PREFIX(x) WASM_RT_PASTE(WASM_RT_MODULE_PREFIX, x)
 
 /* TODO(binji): only use stdint.h types in header */
+#ifndef WASM_RT_CORE_TYPES_DEFINED
+#define WASM_RT_CORE_TYPES_DEFINED
 typedef uint8_t u8;
 typedef int8_t s8;
 typedef uint16_t u16;
@@ -27,6 +29,7 @@ typedef uint64_t u64;
 typedef int64_t s64;
 typedef float f32;
 typedef double f64;
+#endif
 
 extern void WASM_RT_ADD_PREFIX(init)(void);
 %%bottom
diff --git a/test/run-spec-wasm2c.py b/test/run-spec-wasm2c.py
index b3e66c6a..8da98461 100755
--- a/test/run-spec-wasm2c.py
+++ b/test/run-spec-wasm2c.py
@@ -335,7 +335,11 @@ class CWriter(object):
 
 def Compile(cc, c_filename, out_dir, *args):
     o_filename = utils.ChangeDir(utils.ChangeExt(c_filename, '.o'), out_dir)
-    cc.RunWithArgs('-c', c_filename, '-o', o_filename, *args)
+    cc.RunWithArgs('-c', c_filename, '-o', o_filename,
+                   '-Wall', '-Werror', '-Wno-unused',
+                   '-Wno-tautological-constant-out-of-range-compare',
+                   '-std=c99', '-D_DEFAULT_SOURCE',
+                   *args)
     return o_filename
 
 
@@ -401,7 +405,8 @@ def main(args):
         wasm2c.AppendOptionalArgs({
             '--enable-multi-memory': options.enable_multi_memory})
 
-        cc = utils.Executable(options.cc, *options.cflags)
+        cc = utils.Executable(options.cc, *options.cflags, forward_stderr=True,
+                              forward_stdout=True)
         cc.verbose = options.print_cmd
 
         with open(json_file_path) as json_file:
@@ -436,7 +441,7 @@ def main(args):
                 o_filenames.append(Compile(cc, c_filename, out_dir, includes, defines))
 
         if options.compile:
-            o_filenames.append(Compile(cc, main_filename, out_dir, includes, defines))
+            o_filenames.append(Compile(cc, main_filename, out_dir, includes))
             main_exe = utils.ChangeExt(json_file_path, '')
             Link(cc, o_filenames, main_exe, '-lm')
 
diff --git a/wasm2c/wasm-rt-impl.h b/wasm2c/wasm-rt-impl.h
index 39d5ed93..e784fb24 100644
--- a/wasm2c/wasm-rt-impl.h
+++ b/wasm2c/wasm-rt-impl.h
@@ -62,4 +62,4 @@ extern uint32_t g_saved_call_stack_depth;
 }
 #endif
 
-#endif // WASM_RT_IMPL_H_
+#endif /* WASM_RT_IMPL_H_ */