[lld] r278071 - The first string table entry should be a null terminated space, not just null.
Pete Cooper via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 8 16:20:04 PDT 2016
Author: pete
Date: Mon Aug 8 18:20:04 2016
New Revision: 278071
URL: http://llvm.org/viewvc/llvm-project?rev=278071&view=rev
Log:
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 ' '.
Added:
lld/trunk/test/mach-o/string-table.yaml
Modified:
lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp?rev=278071&r1=278070&r2=278071&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp Mon Aug 8 18:20:04 2016
@@ -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::computeSymbolTable
+ _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);
}
Added: lld/trunk/test/mach-o/string-table.yaml
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/mach-o/string-table.yaml?rev=278071&view=auto
==============================================================================
--- lld/trunk/test/mach-o/string-table.yaml (added)
+++ lld/trunk/test/mach-o/string-table.yaml Mon Aug 8 18:20:04 2016
@@ -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: - ''
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