Commit 5d215cc76b

jacob gw <jacoblevgw@gmail.com>
2021-03-04 22:13:49
stage2 Elf linker: fill in bswapAllFields
I moved it to std.elf since it could be used there and added test
1 parent 0447a2c
Changed files (2)
lib
src
link
lib/std/elf.zig
@@ -422,16 +422,8 @@ pub fn ProgramHeaderIterator(ParseSource: anytype) type {
                 if (self.elf_header.endian == std.builtin.endian) return phdr;
 
                 // Convert fields to native endianness.
-                return Elf64_Phdr{
-                    .p_type = @byteSwap(@TypeOf(phdr.p_type), phdr.p_type),
-                    .p_offset = @byteSwap(@TypeOf(phdr.p_offset), phdr.p_offset),
-                    .p_vaddr = @byteSwap(@TypeOf(phdr.p_vaddr), phdr.p_vaddr),
-                    .p_paddr = @byteSwap(@TypeOf(phdr.p_paddr), phdr.p_paddr),
-                    .p_filesz = @byteSwap(@TypeOf(phdr.p_filesz), phdr.p_filesz),
-                    .p_memsz = @byteSwap(@TypeOf(phdr.p_memsz), phdr.p_memsz),
-                    .p_flags = @byteSwap(@TypeOf(phdr.p_flags), phdr.p_flags),
-                    .p_align = @byteSwap(@TypeOf(phdr.p_align), phdr.p_align),
-                };
+                bswapAllFields(Elf64_Phdr, &phdr);
+                return phdr;
             }
 
             var phdr: Elf32_Phdr = undefined;
@@ -442,16 +434,7 @@ pub fn ProgramHeaderIterator(ParseSource: anytype) type {
             // ELF endianness does NOT match native endianness.
             if (self.elf_header.endian != std.builtin.endian) {
                 // Convert fields to native endianness.
-                phdr = .{
-                    .p_type = @byteSwap(@TypeOf(phdr.p_type), phdr.p_type),
-                    .p_offset = @byteSwap(@TypeOf(phdr.p_offset), phdr.p_offset),
-                    .p_vaddr = @byteSwap(@TypeOf(phdr.p_vaddr), phdr.p_vaddr),
-                    .p_paddr = @byteSwap(@TypeOf(phdr.p_paddr), phdr.p_paddr),
-                    .p_filesz = @byteSwap(@TypeOf(phdr.p_filesz), phdr.p_filesz),
-                    .p_memsz = @byteSwap(@TypeOf(phdr.p_memsz), phdr.p_memsz),
-                    .p_flags = @byteSwap(@TypeOf(phdr.p_flags), phdr.p_flags),
-                    .p_align = @byteSwap(@TypeOf(phdr.p_align), phdr.p_align),
-                };
+                bswapAllFields(Elf32_Phdr, &phdr);
             }
 
             // Convert 32-bit header to 64-bit.
@@ -562,6 +545,26 @@ pub fn int32(need_bswap: bool, int_32: anytype, comptime Int64: anytype) Int64 {
     }
 }
 
+pub fn bswapAllFields(comptime S: type, ptr: *S) void {
+    if (@typeInfo(S) != .Struct) @compileError("bswapAllFields expects a struct as the first argument");
+    inline for (std.meta.fields(S)) |f| {
+        @field(ptr, f.name) = @byteSwap(f.field_type, @field(ptr, f.name));
+    }
+}
+test "bswapAllFields" {
+    var s: Elf32_Chdr = .{
+        .ch_type = 0x12341234,
+        .ch_size = 0x56785678,
+        .ch_addralign = 0x12124242,
+    };
+    bswapAllFields(Elf32_Chdr, &s);
+    std.testing.expectEqual(Elf32_Chdr{
+        .ch_type = 0x34123412,
+        .ch_size = 0x78567856,
+        .ch_addralign = 0x42421212,
+    }, s);
+}
+
 pub const EI_NIDENT = 16;
 
 pub const EI_CLASS = 4;
src/link/Elf.zig
@@ -1107,7 +1107,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
                 for (buf) |*phdr, i| {
                     phdr.* = progHeaderTo32(self.program_headers.items[i]);
                     if (foreign_endian) {
-                        bswapAllFields(elf.Elf32_Phdr, phdr);
+                        std.elf.bswapAllFields(elf.Elf32_Phdr, phdr);
                     }
                 }
                 try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), self.phdr_table_offset.?);
@@ -1119,7 +1119,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
                 for (buf) |*phdr, i| {
                     phdr.* = self.program_headers.items[i];
                     if (foreign_endian) {
-                        bswapAllFields(elf.Elf64_Phdr, phdr);
+                        std.elf.bswapAllFields(elf.Elf64_Phdr, phdr);
                     }
                 }
                 try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), self.phdr_table_offset.?);
@@ -1196,7 +1196,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
                     shdr.* = sectHeaderTo32(self.sections.items[i]);
                     log.debug("writing section {}\n", .{shdr.*});
                     if (foreign_endian) {
-                        bswapAllFields(elf.Elf32_Shdr, shdr);
+                        std.elf.bswapAllFields(elf.Elf32_Shdr, shdr);
                     }
                 }
                 try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), self.shdr_table_offset.?);
@@ -1209,7 +1209,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation) !void {
                     shdr.* = self.sections.items[i];
                     log.debug("writing section {}\n", .{shdr.*});
                     if (foreign_endian) {
-                        bswapAllFields(elf.Elf64_Shdr, shdr);
+                        std.elf.bswapAllFields(elf.Elf64_Shdr, shdr);
                     }
                 }
                 try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), self.shdr_table_offset.?);
@@ -2787,14 +2787,14 @@ fn writeProgHeader(self: *Elf, index: usize) !void {
         .p32 => {
             var phdr = [1]elf.Elf32_Phdr{progHeaderTo32(self.program_headers.items[index])};
             if (foreign_endian) {
-                bswapAllFields(elf.Elf32_Phdr, &phdr[0]);
+                std.elf.bswapAllFields(elf.Elf32_Phdr, &phdr[0]);
             }
             return self.base.file.?.pwriteAll(mem.sliceAsBytes(&phdr), offset);
         },
         .p64 => {
             var phdr = [1]elf.Elf64_Phdr{self.program_headers.items[index]};
             if (foreign_endian) {
-                bswapAllFields(elf.Elf64_Phdr, &phdr[0]);
+                std.elf.bswapAllFields(elf.Elf64_Phdr, &phdr[0]);
             }
             return self.base.file.?.pwriteAll(mem.sliceAsBytes(&phdr), offset);
         },
@@ -2808,7 +2808,7 @@ fn writeSectHeader(self: *Elf, index: usize) !void {
             var shdr: [1]elf.Elf32_Shdr = undefined;
             shdr[0] = sectHeaderTo32(self.sections.items[index]);
             if (foreign_endian) {
-                bswapAllFields(elf.Elf32_Shdr, &shdr[0]);
+                std.elf.bswapAllFields(elf.Elf32_Shdr, &shdr[0]);
             }
             const offset = self.shdr_table_offset.? + index * @sizeOf(elf.Elf32_Shdr);
             return self.base.file.?.pwriteAll(mem.sliceAsBytes(&shdr), offset);
@@ -2816,7 +2816,7 @@ fn writeSectHeader(self: *Elf, index: usize) !void {
         .p64 => {
             var shdr = [1]elf.Elf64_Shdr{self.sections.items[index]};
             if (foreign_endian) {
-                bswapAllFields(elf.Elf64_Shdr, &shdr[0]);
+                std.elf.bswapAllFields(elf.Elf64_Shdr, &shdr[0]);
             }
             const offset = self.shdr_table_offset.? + index * @sizeOf(elf.Elf64_Shdr);
             return self.base.file.?.pwriteAll(mem.sliceAsBytes(&shdr), offset);
@@ -2914,7 +2914,7 @@ fn writeSymbol(self: *Elf, index: usize) !void {
                 },
             };
             if (foreign_endian) {
-                bswapAllFields(elf.Elf32_Sym, &sym[0]);
+                std.elf.bswapAllFields(elf.Elf32_Sym, &sym[0]);
             }
             const off = syms_sect.sh_offset + @sizeOf(elf.Elf32_Sym) * index;
             try self.base.file.?.pwriteAll(mem.sliceAsBytes(sym[0..1]), off);
@@ -2922,7 +2922,7 @@ fn writeSymbol(self: *Elf, index: usize) !void {
         .p64 => {
             var sym = [1]elf.Elf64_Sym{self.local_symbols.items[index]};
             if (foreign_endian) {
-                bswapAllFields(elf.Elf64_Sym, &sym[0]);
+                std.elf.bswapAllFields(elf.Elf64_Sym, &sym[0]);
             }
             const off = syms_sect.sh_offset + @sizeOf(elf.Elf64_Sym) * index;
             try self.base.file.?.pwriteAll(mem.sliceAsBytes(sym[0..1]), off);
@@ -2953,7 +2953,7 @@ fn writeAllGlobalSymbols(self: *Elf) !void {
                     .st_shndx = self.global_symbols.items[i].st_shndx,
                 };
                 if (foreign_endian) {
-                    bswapAllFields(elf.Elf32_Sym, sym);
+                    std.elf.bswapAllFields(elf.Elf32_Sym, sym);
                 }
             }
             try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), global_syms_off);
@@ -2972,7 +2972,7 @@ fn writeAllGlobalSymbols(self: *Elf) !void {
                     .st_shndx = self.global_symbols.items[i].st_shndx,
                 };
                 if (foreign_endian) {
-                    bswapAllFields(elf.Elf64_Sym, sym);
+                    std.elf.bswapAllFields(elf.Elf64_Sym, sym);
                 }
             }
             try self.base.file.?.pwriteAll(mem.sliceAsBytes(buf), global_syms_off);
@@ -3188,10 +3188,6 @@ fn pwriteDbgInfoNops(
     try self.base.file.?.pwritevAll(vecs[0..vec_index], offset - prev_padding_size);
 }
 
-fn bswapAllFields(comptime S: type, ptr: *S) void {
-    @panic("TODO implement bswapAllFields");
-}
-
 fn progHeaderTo32(phdr: elf.Elf64_Phdr) elf.Elf32_Phdr {
     return .{
         .p_type = phdr.p_type,