From 5559b2493526d5ff38a66cb38b276c2a7e93b0c9 Mon Sep 17 00:00:00 2001 From: Pete Cooper Date: Mon, 8 Aug 2016 23:20:04 +0000 Subject: [PATCH] The first string table entry should be a null terminated space, not just null. This matches the behaviour of ld64 which initializes the string table with ' ' then '\0'. lld only had the '\0' and needed the ' '. llvm-svn: 278071 --- .../MachO/MachONormalizedFileBinaryWriter.cpp | 7 ++- lld/test/mach-o/string-table.yaml | 66 ++++++++++++++++++++++ 2 files changed, 71 insertions(+), 2 deletions(-) create mode 100644 lld/test/mach-o/string-table.yaml diff --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp index a0609a5..89b0f6f 100644 --- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp +++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp @@ -1106,7 +1106,9 @@ void MachOFileLayout::writeSymbolTable() { // Write symbol table and symbol strings in parallel. uint32_t symOffset = _startOfSymbols; uint32_t strOffset = _startOfSymbolStrings; - _buffer[strOffset++] = '\0'; // Reserve n_strx offset of zero to mean no name. + // Reserve n_strx offset of zero to mean no name. + _buffer[strOffset++] = ' '; + _buffer[strOffset++] = '\0'; appendSymbols(_file.stabsSymbols, symOffset, strOffset); appendSymbols(_file.localSymbols, symOffset, strOffset); appendSymbols(_file.globalSymbols, symOffset, strOffset); @@ -1448,7 +1450,8 @@ void MachOFileLayout::computeSymbolTableSizes() { + _file.localSymbols.size() + _file.globalSymbols.size() + _file.undefinedSymbols.size()); - _symbolStringPoolSize = 1; // Always reserve 1-byte for the empty string. + // Always reserve 1-byte for the empty string and 1-byte for its terminator. + _symbolStringPoolSize = 2; for (const Symbol &sym : _file.stabsSymbols) { _symbolStringPoolSize += (sym.name.size()+1); } diff --git a/lld/test/mach-o/string-table.yaml b/lld/test/mach-o/string-table.yaml new file mode 100644 index 0000000..eec2c77 --- /dev/null +++ b/lld/test/mach-o/string-table.yaml @@ -0,0 +1,66 @@ +# RUN: lld -flavor darwin -arch i386 %s %p/Inputs/hello-world-x86.yaml -o %t +# RUN: obj2yaml %t | FileCheck %s +# +# Test that the string table contains a ' ' as its first symbol +# + +--- !mach-o +arch: x86 +file-type: MH_OBJECT +flags: [ MH_SUBSECTIONS_VIA_SYMBOLS ] +sections: + - segment: __TEXT + section: __text + type: S_REGULAR + attributes: [ S_ATTR_PURE_INSTRUCTIONS, S_ATTR_SOME_INSTRUCTIONS ] + address: 0x0000000000000000 + content: [ 0x55, 0x89, 0xE5, 0x83, 0xEC, 0x08, 0xE8, 0x00, + 0x00, 0x00, 0x00, 0x58, 0x8D, 0x80, 0x16, 0x00, + 0x00, 0x00, 0x89, 0x04, 0x24, 0xE8, 0xE6, 0xFF, + 0xFF, 0xFF, 0x31, 0xC0, 0x83, 0xC4, 0x08, 0x5D, + 0xC3 ] + relocations: + - offset: 0x00000016 + type: GENERIC_RELOC_VANILLA + length: 2 + pc-rel: true + extern: true + symbol: 1 + - offset: 0x0000000E + scattered: true + type: GENERIC_RELOC_LOCAL_SECTDIFF + length: 2 + pc-rel: false + value: 0x00000021 + - offset: 0x00000000 + scattered: true + type: GENERIC_RELOC_PAIR + length: 2 + pc-rel: false + value: 0x0000000B + - segment: __TEXT + section: __cstring + type: S_CSTRING_LITERALS + attributes: [ ] + address: 0x0000000000000021 + content: [ 0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x0A, 0x00 ] +global-symbols: + - name: _main + type: N_SECT + scope: [ N_EXT ] + sect: 1 + value: 0x0000000000000000 +undefined-symbols: + - name: _printf + type: N_UNDF + scope: [ N_EXT ] + value: 0x0000000000000000 +... + +# CHECK: StringTable: +# CHECK-NEXT: - ' ' +# CHECK-NEXT: - __mh_execute_header +# CHECK-NEXT: - _main +# CHECK-NEXT: - _printf +# CHECK-NEXT: - dyld_stub_binder +# CHECK-NEXT: - '' -- 2.7.4