tccelf.c: write section headers before sections

also avoid zero lenght PT_LOAD segments (which some musl
loaders seem to dislike)

Also:
- tccasm.c: support .section with flags: .section .xyz,"wx"
  (fixes e4d874d)
- tccgen,c:  add __builtin_unreachable()
- tccdefs.h: #define __has_attribute(x) 0
- tcc.c: tidy help for -std
- tcctools.c/execvp_win32: quote strings more correctly
- x86_64-gen.c:win32: set unwind begin-address to function-start
- github action: add aarch64-osx (M1) & i386-win32
- configure: consider 32-bit build on MSYS64 native

.github/workflows/build.yml

@@ -10,36 +10,52 @@ jobs:
     timeout-minutes: 2
     steps:
     - uses: actions/checkout@v4
-    - name: make & test tcc
+    - name: make & test tcc (x86_64-linux)
       run: ./configure && make && make test -k
 
   test-x86_64-osx:
     runs-on: macos-12
     timeout-minutes: 2
     steps:
     - uses: actions/checkout@v4
-    - name: make & test tcc
-      run: ./configure --config-codesign=no && make && make test -k
+    - name: make & test tcc (x86_64-osx)
+      run: ./configure && make && make test -k
+
+  test-aarch64-osx:
+    runs-on: macos-14
+    timeout-minutes: 2
+    steps:
+    - uses: actions/checkout@v4
+    - name: make & test tcc (aarch64-osx)
+      run: ./configure && make && make test -k
 
-  test-x86_64-win32:
+  test-x86-win32:
     runs-on: windows-2019
-    timeout-minutes: 4
+    timeout-minutes: 6
     steps:
     - uses: actions/checkout@v4
-    - name: make & test tcc
+    - name: make & test tcc (x86_64-win32)
       shell: cmd
       run: |
         set MSYS2_PATH_TYPE=inherit
         set MSYSTEM=MINGW64
         set CHERE_INVOKING=yes
         C:\msys64\usr\bin\bash -l -c "./configure && make && make test -k"
+    - name: make & test tcc (i386-win32)
+      shell: cmd
+      run: |
+        set MSYS2_PATH_TYPE=inherit
+        set MSYSTEM=MINGW32
+        set CHERE_INVOKING=yes
+        C:\msys64\usr\bin\bash -l -c "./configure && make clean all && make test -k"
 
   test-armv7-linux:
     runs-on: ubuntu-20.04
     timeout-minutes: 6
     steps:
     - uses: actions/checkout@v4
     - uses: uraimo/run-on-arch-action@v2
+      name: make & test tcc (armv7-linux)
       with:
         arch: armv7
         distro: ubuntu20.04
@@ -57,6 +73,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - uses: uraimo/run-on-arch-action@v2
+      name: make & test tcc (aarch64-linux)
       with:
         arch: aarch64
         distro: ubuntu20.04
@@ -74,6 +91,7 @@ jobs:
     steps:
     - uses: actions/checkout@v4
     - uses: uraimo/run-on-arch-action@v2
+      name: make & test tcc (riscv64-linux)
       with:
         arch: riscv64
         distro: ubuntu20.04

Makefile

@@ -69,7 +69,10 @@ else
  ifdef CONFIG_OSX
   NATIVE_TARGET = $(ARCH)-osx
   ifneq ($(CC_NAME),tcc)
-    LDFLAGS += -flat_namespace -undefined warning
+    LDFLAGS += -flat_namespace
+    ifneq (1,$(shell expr $(GCC_MAJOR) ">=" 15))
+      LDFLAGS += -undefined warning # depreciated in clang >= 15.0
+    endif
   endif
   export MACOSX_DEPLOYMENT_TARGET := 10.6
  endif

configure

@@ -227,10 +227,12 @@ fi
 
 # OS specific
 buildos=$(uname)
+cpu_sys=$(uname -m)
 
 case $buildos in
   Windows_NT|MINGW*|MSYS*|CYGWIN*)
     buildos="WIN32"
+    test "$MSYSTEM" = "MINGW32" && cpu_sys=i386
   ;;
   Linux)
     if test "$(uname -o)" = "Android"; then
@@ -248,7 +250,6 @@ else
   default targetos "$buildos"
 fi
 
-cpu_sys=$(uname -m)
 default cpu "$cpu_sys"
 cpu_set="$cpu"
 

include/tccdefs.h

@@ -152,6 +152,7 @@
     #define  __PRETTY_FUNCTION__ __FUNCTION__
     #define __has_builtin(x) 0
     #define __has_feature(x) 0
+    #define __has_atttribute(x) 0
     /* C23 Keywords */
     #define _Nonnull
     #define _Nullable

tcc.c

@@ -33,8 +33,6 @@ static const char help[] =
     "  -o outfile   set output filename\n"
     "  -run         run compiled source\n"
     "  -fflag       set or reset (with 'no-' prefix) 'flag' (see tcc -hh)\n"
-    "  -std=(c99|gnu99)     Conform to the ISO 1999 C standard (default).\n"
-    "  -std=(c11|gnu11)    Conform to the ISO 2011 C standard.\n"
     "  -Wwarning    set or reset (with 'no-' prefix) 'warning' (see tcc -hh)\n"
     "  -w           disable all warnings\n"
     "  -v --version show version\n"
@@ -69,6 +67,7 @@ static const char help[] =
     "  -bt[N]       link with backtrace (stack dump) support [show max N callers]\n"
 #endif
     "Misc. options:\n"
+    "  -std=version define __STDC_VERSION__ according to version (c11/gnu11)\n"
     "  -x[c|a|b|n]  specify type of the next infile (C,ASM,BIN,NONE)\n"
     "  -nostdinc    do not use standard system include paths\n"
     "  -nostdlib    do not link with standard crt and libraries\n"

tccasm.c

@@ -857,6 +857,7 @@ static void asm_parse_directive(TCCState *s1, int global)
         {
             char sname[256];
 	    int old_nb_section = s1->nb_sections;
+            int flags = SHF_ALLOC;
 
 	    tok1 = tok;
             /* XXX: support more options */
@@ -870,10 +871,17 @@ static void asm_parse_directive(TCCState *s1, int global)
                 next();
             }
             if (tok == ',') {
+                const char *p;
                 /* skip section options */
                 next();
                 if (tok != TOK_STR)
                     expect("string constant");
+                for (p = tokc.str.data; *p; ++p) {
+                    if (*p == 'w')
+                        flags |= SHF_WRITE;
+                    if (*p == 'x')
+                        flags |= SHF_EXECINSTR;
+                }
                 next();
                 if (tok == ',') {
                     next();
@@ -883,19 +891,17 @@ static void asm_parse_directive(TCCState *s1, int global)
                 }
             }
             last_text_section = cur_text_section;
-	    if (tok1 == TOK_ASMDIR_section) {
+	    if (tok1 == TOK_ASMDIR_section)
 	        use_section(s1, sname);
-            /* The section directive supports flags, but they are unsupported.
-            For now, just assume any section contains code. */
-            cur_text_section->sh_flags |= SHF_EXECINSTR;
-        }
 	    else
 	        push_section(s1, sname);
 	    /* If we just allocated a new section reset its alignment to
 	       1.  new_section normally acts for GCC compatibility and
 	       sets alignment to PTR_SIZE.  The assembler behaves different. */
-	    if (old_nb_section != s1->nb_sections)
+	    if (old_nb_section != s1->nb_sections) {
 	        cur_text_section->sh_addralign = 1;
+	        cur_text_section->sh_flags = flags;
+            }
         }
         break;
     case TOK_ASMDIR_previous: