Big endian build to test bitfields

.github/workflows/buildAndTest.yaml

@@ -27,6 +27,47 @@ jobs:
     - name: Examples test
       run: make test all DWARF_VER_FORCE=${{matrix.dwarf-version}}
 
+  ubuntu_big_endian:
+    # pretty slow since it's running on qemu. we may disable it periodically
+    # taken from https://github.com/marketplace/actions/run-on-architecture
+    # s390x is big endian with Ubuntu_latest which
+    # also has go-lang for linux: https://go.dev/dl/
+    # https://go.dev/dl/go1.23.0.linux-s390x.tar.gz
+    # GO_TELEMETRY_CHILD=off
+    # The host should always be Linux.
+    runs-on: ubuntu-22.04
+    name: ubuntu (s390x - big endian)
+    steps:
+      - uses: actions/checkout@v4
+      - name: Download Go
+        run: curl -fsSL -o go.tar.gz https://go.dev/dl/go1.22.0.linux-s390x.tar.gz
+      - uses: uraimo/run-on-arch-action@v2
+        name: Run commands
+        id: runcmd
+        with:
+          arch: s390x
+          distro: ubuntu_latest
+
+          # Not required, but speeds up builds by storing container images in
+          # a GitHub package registry.
+          githubToken: ${{ github.token }}
+
+          # Set an output parameter `uname` for use in subsequent steps
+          run: |
+            set -x
+            uname -a
+            apt update && apt-get install -y ca-certificates pkg-config make gcc g++ check # todo: libffi-dev
+
+            tar -C /usr/local -xzf go.tar.gz && rm go.tar.gz
+            export PATH=$PATH:/usr/local/go/bin
+            go version
+
+            export GO111MODULE=on
+            go test -cover ./...
+            go build
+
+            make test all
+
   macos:
     runs-on: macos-latest
     strategy:
@@ -70,7 +111,7 @@ jobs:
         msystem: ${{matrix.sys}}
         update: true
         install: base-devel git pkg-config mingw-w64-${{matrix.env}}-check mingw-w64-${{matrix.env}}-toolchain
-        path-type: inherit # to be able to find go
+        path-type: inherit # to be able to find go in PATH
     - name: Checkout code
       uses: actions/checkout@v3
     - name: Test
@@ -80,4 +121,4 @@ jobs:
     - name: Build
       run: go build
     - name: Examples test
-      run: make test all
+      run: make test all

src/entry.c

@@ -443,11 +443,10 @@ int metac_entry_member_bitfield_offsets(metac_entry_t *p_memb_entry,
         *p_bit_offset = _data_bit_offset & 0x7;
     } else  if (p_memb_entry->member_info.p_data_bit_offset != NULL) { /* dwarf 4 */
         // in data
-
         metac_offset_t _data_bit_offset = *p_memb_entry->member_info.p_data_bit_offset;
         *p_bit_size = p_memb_entry->member_info.p_bit_size != NULL?(*p_memb_entry->member_info.p_bit_size): 0;
-        // out
 
+        // out
         *p_byte_offset = _data_bit_offset >> 3;
         *p_bit_offset = _data_bit_offset & 0x7;
     }

src/value.c

@@ -133,16 +133,11 @@ static int _entry_bitfield_read(metac_entry_t *p_memb_entry, void * base_addr, v
         // TODO: make it without extra copy if possible
         // TODO: need to make it for both endians
         assert(bit_size != 0);
-        memcpy(buf, base_addr, (bit_offset + bit_size-1)/8 +1);
+        memcpy(buf, base_addr, (bit_offset + bit_size - 1)/8 + 1);
         base_addr = buf;
     } else {
-        assert(metac_entry_parent_count(p_memb_entry) == 1);
-        metac_entry_t * p_memb_parent = metac_entry_parent_entry(p_memb_entry, 0);
-        assert(p_memb_parent != NULL);
-        metac_size_t parent_byte_size = 0;
-        _check_(metac_entry_byte_size(p_memb_parent, &parent_byte_size) != 0, -(EFAULT));
-        assert(parent_byte_size > 0);
-        base_addr += parent_byte_size - byte_offset;
+        base_addr += byte_offset;
+        bit_offset = 8 * var_size - (bit_offset + bit_size);
     }
 
 #define _read_(_type_) \
@@ -194,16 +189,11 @@ static int _entry_bitfield_write(metac_entry_t *p_memb_entry, void * base_addr,
         // TODO: need to make it for both endians
         assert(bit_size != 0);
         base_addr_orig = base_addr;
-        memcpy(buf, base_addr, (bit_offset + bit_size-1)/8 +1);
+        memcpy(buf, base_addr, (bit_offset + bit_size - 1)/8 + 1);
         base_addr = buf;
     } else {
-        assert(metac_entry_parent_count(p_memb_entry) == 1);
-        metac_entry_t * p_memb_parent = metac_entry_parent_entry(p_memb_entry, 0);
-        assert(p_memb_parent != NULL);
-        metac_size_t parent_byte_size = 0;
-        _check_(metac_entry_byte_size(p_memb_parent, &parent_byte_size) != 0, -(EFAULT));
-        assert(parent_byte_size > 0);
-        base_addr += parent_byte_size - byte_offset;
+        base_addr += byte_offset;
+        bit_offset = 8 * var_size - (bit_offset + bit_size);
     }
 
 #define _write_(_type_) \

src/value_base_type.c

@@ -11,7 +11,8 @@ dsprintf_render_with_buf(64)
 #endif
 
 metac_flag_t metac_entry_is_char(metac_entry_t * p_entry) {
-    return metac_entry_check_base_type(p_entry, "char", METAC_ENC_signed_char, sizeof(char)) == 0;
+    return metac_entry_check_base_type(p_entry, "char", METAC_ENC_signed_char, sizeof(char)) == 0 ||
+        metac_entry_check_base_type(p_entry, "char", METAC_ENC_unsigned_char, sizeof(char)) == 0; // some platforms are doing this
 }
 metac_flag_t metac_entry_is_uchar(metac_entry_t * p_entry) {
     return metac_entry_check_base_type(p_entry, "unsigned char", METAC_ENC_unsigned_char, sizeof(unsigned char)) == 0;
@@ -115,7 +116,8 @@ metac_flag_t metac_value_is_ldouble_complex(metac_value_t * p_val) {
 }
 /**/
 int metac_value_char(metac_value_t * p_val, char *p_var) {
-    return metac_value_base_type(p_val, "char", METAC_ENC_signed_char, (void*)p_var, sizeof(*p_var));
+    return (metac_value_base_type(p_val, "char", METAC_ENC_signed_char, (void*)p_var, sizeof(*p_var)) == 0 ||
+        metac_value_base_type(p_val, "char", METAC_ENC_unsigned_char, (void*)p_var, sizeof(*p_var)) == 0)?0:-(EFAULT);
 }
 int metac_value_uchar(metac_value_t * p_val, unsigned char *p_var) {
     return metac_value_base_type(p_val, "unsigned char", METAC_ENC_unsigned_char, (void*)p_var, sizeof(*p_var));
@@ -167,7 +169,8 @@ int metac_value_ldouble_complex(metac_value_t * p_val, long double complex *p_va
 }
 /* */
 int metac_value_set_char(metac_value_t * p_val, char var) {
-    return metac_value_set_base_type(p_val, "char", METAC_ENC_signed_char, &var, sizeof(var));
+    return (metac_value_set_base_type(p_val, "char", METAC_ENC_signed_char, &var, sizeof(var)) == 0 ||
+        metac_value_set_base_type(p_val, "char", METAC_ENC_unsigned_char, &var, sizeof(var)) == 0)?0:-(EFAULT);
 }
 int metac_value_set_uchar(metac_value_t * p_val, unsigned char var) {
     return metac_value_set_base_type(p_val, "unsigned char", METAC_ENC_unsigned_char, &var, sizeof(var));

src/value_base_type_test.c

@@ -17,6 +17,19 @@
 static void test_char(metac_value_t * p_val, char * p_actual_data, metac_flag_t expected_write_err) {
     fail_unless(p_val != NULL, "couldn't create p_val");
 
+    metac_entry_t *p_entry = metac_entry_final_entry(metac_value_entry(p_val), NULL);
+    fail_unless(metac_entry_is_base_type(p_entry)!=0);
+    fail_unless(metac_entry_name(p_entry) != 0, "name is null");
+    fail_unless(strcmp("char", metac_entry_name(p_entry)) == 0, "expected char, got %s", metac_entry_name(p_entry));
+    metac_size_t sz;
+    fail_unless(metac_entry_byte_size(p_entry, &sz) == 0);
+    fail_unless(sz == sizeof(char), "sz got %d, expected %d", (int)sz, (int)sizeof(char));
+    metac_encoding_t enc;
+    fail_unless(metac_entry_base_type_encoding(p_entry, &enc)==0);
+    fail_unless(enc == METAC_ENC_signed_char || enc == METAC_ENC_unsigned_char, "sz got %d, expected %d or %d", 
+        (int)enc, (int)METAC_ENC_signed_char, (int)METAC_ENC_unsigned_char);
+
+
     char target;
     fail_unless(metac_value_is_char(p_val) != 0, "0 metac_value_is_char returned error");
     fail_unless(metac_value_char(p_val, &target) == 0, "0 metac_value_char returned error");

src/value_bitfields_test.c

@@ -11,6 +11,147 @@
 #include "value_base_type.c"
 #include "value_with_args.c"
 
+// uncomment the next line if the test doesn't work
+// #define PRECHECK_DEBUG
+struct {
+    char a:2;
+    char b:3;
+    char c:3; // goes beyond the first char (shoud be moved to the next byte by compiler)
+    int x: 10;
+    long z: 22;
+}precheck_struct;
+METAC_GSYM_LINK(precheck_struct);
+
+#define DUMP_MEM(_start_, _size_) \
+	do { \
+		int i; \
+		unsigned char * p = (unsigned char *)_start_; \
+		for (i=0; i<(_size_); i++) { \
+			fprintf(stderr, "%02x ", (int)*p++); \
+		} \
+		fprintf(stderr, "\n"); \
+	}while(0)
+
+METAC_START_TEST(pre_check) {
+    metac_value_t * p_val = METAC_VALUE_FROM_LINK(precheck_struct);
+    char target;
+    fail_unless(metac_value_char(p_val, &target) != 0, "metac_value_char must return error because p_val isn't char");
+    metac_num_t count = metac_value_member_count(p_val);
+    fail_unless(count != 0, "got empty struct");
+    for (metac_num_t fld_id = 0; fld_id < count; ++fld_id) {
+        metac_value_t * p_mem_val = metac_new_value_by_member_id(p_val, fld_id);
+        metac_entry_t * p_mem_entry = p_mem_val->p_entry;
+
+        metac_entry_t * p_final_entry = metac_entry_final_entry(p_mem_entry, NULL);
+        metac_encoding_t enc;
+        fail_unless(metac_entry_base_type_encoding(p_final_entry, &enc)==0);
+
+        fail_unless(p_mem_entry->kind == METAC_KND_member, "must be member info kind");
+        metac_offset_t byte_offset;
+        metac_offset_t bit_offset;
+        metac_offset_t bit_size;
+        if (p_mem_entry->member_info.p_bit_offset != NULL) {
+#ifdef PRECHECK_DEBUG
+            fprintf(stderr, "DWARF 3, LE %d\n", (int)IS_LITTLE_ENDIAN);
+#endif
+            metac_offset_t  _bit_size = (p_mem_entry->member_info.p_bit_size?(*p_mem_entry->member_info.p_bit_size):0),
+                            _bit_offset = (p_mem_entry->member_info.p_bit_offset?(*p_mem_entry->member_info.p_bit_offset):0),
+                            _byte_size = (p_mem_entry->member_info.p_byte_size?(*p_mem_entry->member_info.p_byte_size):0);
+            metac_offset_t _data_bit_offset = (p_mem_entry->member_info.byte_offset + _byte_size) * 8 - (_bit_offset + _bit_size);
+            byte_offset = _data_bit_offset >> 3;
+            bit_offset = _data_bit_offset & 0x7;
+            bit_size = _bit_size;
+#ifdef PRECHECK_DEBUG
+            fprintf(stderr, "fld %4s, bit_offset %d, bit_size %d, location %d byte_size %d=> byte_offset %d, bit_offset %d bit_size %d\n",
+                p_mem_entry->name, (int)(_bit_offset), (int)_bit_size, (int)p_mem_entry->member_info.byte_offset, (int)_byte_size,
+                (int)byte_offset, (int)bit_offset, (int)bit_size);
+#endif
+        } else  if (p_mem_entry->member_info.p_data_bit_offset != NULL) { // test DWARF 4 approach
+#ifdef PRECHECK_DEBUG
+            fprintf(stderr, "DWARF 4, LE %d\n", (int)IS_LITTLE_ENDIAN);
+#endif
+            metac_offset_t _data_bit_offset = *p_mem_entry->member_info.p_data_bit_offset;
+            metac_offset_t _bit_size = p_mem_entry->member_info.p_bit_size != NULL?(*p_mem_entry->member_info.p_bit_size): 0;
+            byte_offset = _data_bit_offset >> 3;
+            bit_offset = _data_bit_offset & 0x7;
+            bit_size = _bit_size;
+#ifdef PRECHECK_DEBUG
+            fprintf(stderr, "fld %4s, data_bit_offset %d, bit_size %d => byte_offset %d, bit_offset %d bit_size %d\n",
+                p_mem_entry->name, (int)(_data_bit_offset), (int)bit_size,
+                (int)byte_offset, (int)bit_offset, (int)bit_size);
+#endif
+        }
+        void * base_addr = NULL;
+        switch (fld_id) {
+        case 0: // field 'a'
+            fail_unless(strcmp(p_mem_entry->name, "a") == 0);
+            precheck_struct.a = 0;
+
+            if (IS_LITTLE_ENDIAN) {
+                base_addr = p_mem_val->addr + byte_offset;
+            } else {
+                fail_unless(p_mem_entry->parents_count == 1 && p_mem_entry->parents[0]->structure_type_info.byte_size != 0);
+                base_addr = p_mem_val->addr + byte_offset;
+                bit_offset = 8 - (bit_offset + bit_size);
+            }
+            do {
+#ifdef PRECHECK_DEBUG
+                fprintf(stderr, "value %d: ", (int)precheck_struct.a);
+                DUMP_MEM(&precheck_struct, sizeof(precheck_struct));
+#endif
+                fail_unless(base_addr != NULL, "based addr mustn't be NULL");
+                char data = *((char*)base_addr);
+#ifdef PRECHECK_DEBUG
+                fprintf(stderr, "read %x, bit_offset %x, mask %x => %x\n", (int)data, (int)bit_offset,
+                    (int)((1 << bit_size) - 1),
+                    (int)(data >> bit_offset) & ((1 << bit_size) - 1));
+#endif
+                data = (data >> bit_offset) & ((1 << bit_size) - 1);
+                if ((enc == METAC_ENC_signed_char) && (data & (1 << (bit_size-1)))) { 
+                    data = ((0xff) << ((bit_size))) ^ data; 
+                }
+                char exp_data = precheck_struct.a;
+                fail_unless(exp_data == data, "expected %x, got %x", exp_data, data);
+                ++precheck_struct.a;
+            }while(precheck_struct.a != 0);
+            break;
+        case 2: // field 'c'
+            fail_unless(strcmp(p_mem_entry->name, "c") == 0);
+            precheck_struct.c = 0;
+            if (IS_LITTLE_ENDIAN) {
+                base_addr = p_mem_val->addr + byte_offset;
+            } else {
+                fail_unless(p_mem_entry->parents_count == 1 && p_mem_entry->parents[0]->structure_type_info.byte_size != 0);
+                base_addr = p_mem_val->addr + byte_offset;
+                bit_offset = 8 - (bit_offset + bit_size);
+            }
+            do {
+#ifdef PRECHECK_DEBUG
+                fprintf(stderr, "value %d: ", (int)precheck_struct.c);
+                DUMP_MEM(&precheck_struct, sizeof(precheck_struct));
+#endif
+                fail_unless(base_addr != NULL, "based addr mustn't be NULL");
+                char data = *((char*)base_addr);
+#ifdef PRECHECK_DEBUG
+                fprintf(stderr, "read %x, bit_offset %x, mask %x => %x\n", (int)data, (int)bit_offset,
+                    (int)((1 << bit_size) - 1),
+                    (int)(data >> bit_offset) & ((1 << bit_size) - 1));
+#endif
+                data = (data >> bit_offset) & ((1 << bit_size) - 1);
+                if ((enc == METAC_ENC_signed_char) && (data & (1 << (bit_size-1)))) { 
+                    data = ((0xff) << ((bit_size))) ^ data; 
+                }
+                char exp_data = precheck_struct.c;
+                fail_unless(exp_data == data, "expected %x, got %x", exp_data, data);
+                ++precheck_struct.c;
+            }while(precheck_struct.c != 0);
+            break;
+        }
+        metac_value_delete(p_mem_val);
+    }
+    metac_value_delete(p_val);
+}END_TEST
+
 struct {
     char a:3;
     unsigned char b:3;