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🍒 [lldb][MachO] Fix inspection of global variables that start with 'O' #11542

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🍒 [lldb][MachO] Fix inspection of global variables that start with 'O' #11542

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f4f619b
[lldb][test] Allow '.c' files to be used as shell tests (#161520)
Michael137 Oct 1, 2025
52fd210
[lldb][MachO] Fix inspection of global variables that start with 'O' …
Michael137 Oct 1, 2025
d6cf2a1
[lldb][test] XFAIL TestGlobalSymbolObjCConflict.c on Windows
Michael137 Oct 2, 2025
b24ddff
Reland "[lldb][MachO][NFC] Extract ObjC metadata symbol parsing into …
Michael137 Oct 2, 2025
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180 changes: 55 additions & 125 deletions lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2306,6 +2306,43 @@ static bool ParseTrieEntries(DataExtractor &data, lldb::offset_t offset,
return true;
}

static bool
TryParseV2ObjCMetadataSymbol(const char *&symbol_name,
const char *&symbol_name_non_abi_mangled,
SymbolType &type) {
static constexpr llvm::StringLiteral g_objc_v2_prefix_class("_OBJC_CLASS_$_");
static constexpr llvm::StringLiteral g_objc_v2_prefix_metaclass(
"_OBJC_METACLASS_$_");
static constexpr llvm::StringLiteral g_objc_v2_prefix_ivar("_OBJC_IVAR_$_");

llvm::StringRef symbol_name_ref(symbol_name);
if (symbol_name_ref.empty())
return false;

if (symbol_name_ref.starts_with(g_objc_v2_prefix_class)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_class.size();
type = eSymbolTypeObjCClass;
return true;
}

if (symbol_name_ref.starts_with(g_objc_v2_prefix_metaclass)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_metaclass.size();
type = eSymbolTypeObjCMetaClass;
return true;
}

if (symbol_name_ref.starts_with(g_objc_v2_prefix_ivar)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_ivar.size();
type = eSymbolTypeObjCIVar;
return true;
}

return false;
}

static SymbolType GetSymbolType(const char *&symbol_name,
bool &demangled_is_synthesized,
const SectionSP &text_section_sp,
Expand Down Expand Up @@ -2422,9 +2459,6 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
lldb::offset_t offset = MachHeaderSizeFromMagic(m_header.magic);
uint32_t i;
FileSpecList dylib_files;
llvm::StringRef g_objc_v2_prefix_class("_OBJC_CLASS_$_");
llvm::StringRef g_objc_v2_prefix_metaclass("_OBJC_METACLASS_$_");
llvm::StringRef g_objc_v2_prefix_ivar("_OBJC_IVAR_$_");
UUID image_uuid;

for (i = 0; i < m_header.ncmds; ++i) {
Expand Down Expand Up @@ -3057,36 +3091,15 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
is_gsym = true;
sym[sym_idx].SetExternal(true);

if (symbol_name && symbol_name[0] == '_' &&
symbol_name[1] == 'O') {
llvm::StringRef symbol_name_ref(symbol_name);
if (symbol_name_ref.starts_with(
g_objc_v2_prefix_class)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_class.size();
type = eSymbolTypeObjCClass;
demangled_is_synthesized = true;

} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_metaclass)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_metaclass.size();
type = eSymbolTypeObjCMetaClass;
demangled_is_synthesized = true;
} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_ivar)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_ivar.size();
type = eSymbolTypeObjCIVar;
demangled_is_synthesized = true;
}
if (TryParseV2ObjCMetadataSymbol(
symbol_name, symbol_name_non_abi_mangled,
type)) {
demangled_is_synthesized = true;
} else {
if (nlist.n_value != 0)
symbol_section = section_info.GetSection(
nlist.n_sect, nlist.n_value);

type = eSymbolTypeData;
}
break;
Expand Down Expand Up @@ -3572,48 +3585,10 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
symbol_sect_name) {
type = eSymbolTypeRuntime;

if (symbol_name) {
llvm::StringRef symbol_name_ref(symbol_name);
if (symbol_name_ref.starts_with("_OBJC_")) {
llvm::StringRef
g_objc_v2_prefix_class(
"_OBJC_CLASS_$_");
llvm::StringRef
g_objc_v2_prefix_metaclass(
"_OBJC_METACLASS_$_");
llvm::StringRef
g_objc_v2_prefix_ivar("_OBJC_IVAR_$_");
if (symbol_name_ref.starts_with(
g_objc_v2_prefix_class)) {
symbol_name_non_abi_mangled =
symbol_name + 1;
symbol_name =
symbol_name +
g_objc_v2_prefix_class.size();
type = eSymbolTypeObjCClass;
demangled_is_synthesized = true;
} else if (
symbol_name_ref.starts_with(
g_objc_v2_prefix_metaclass)) {
symbol_name_non_abi_mangled =
symbol_name + 1;
symbol_name =
symbol_name +
g_objc_v2_prefix_metaclass.size();
type = eSymbolTypeObjCMetaClass;
demangled_is_synthesized = true;
} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_ivar)) {
symbol_name_non_abi_mangled =
symbol_name + 1;
symbol_name =
symbol_name +
g_objc_v2_prefix_ivar.size();
type = eSymbolTypeObjCIVar;
demangled_is_synthesized = true;
}
}
}
if (TryParseV2ObjCMetadataSymbol(
symbol_name,
symbol_name_non_abi_mangled, type))
demangled_is_synthesized = true;
} else if (symbol_sect_name &&
::strstr(symbol_sect_name,
"__gcc_except_tab") ==
Expand Down Expand Up @@ -3970,7 +3945,7 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {

if (is_debug) {
switch (nlist.n_type) {
case N_GSYM:
case N_GSYM: {
// global symbol: name,,NO_SECT,type,0
// Sometimes the N_GSYM value contains the address.

Expand All @@ -3986,33 +3961,17 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
is_gsym = true;
sym[sym_idx].SetExternal(true);

if (symbol_name && symbol_name[0] == '_' && symbol_name[1] == 'O') {
llvm::StringRef symbol_name_ref(symbol_name);
if (symbol_name_ref.starts_with(g_objc_v2_prefix_class)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_class.size();
type = eSymbolTypeObjCClass;
demangled_is_synthesized = true;

} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_metaclass)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_metaclass.size();
type = eSymbolTypeObjCMetaClass;
demangled_is_synthesized = true;
} else if (symbol_name_ref.starts_with(g_objc_v2_prefix_ivar)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name = symbol_name + g_objc_v2_prefix_ivar.size();
type = eSymbolTypeObjCIVar;
demangled_is_synthesized = true;
}
if (TryParseV2ObjCMetadataSymbol(symbol_name,
symbol_name_non_abi_mangled, type)) {
demangled_is_synthesized = true;
} else {
if (nlist.n_value != 0)
symbol_section =
section_info.GetSection(nlist.n_sect, nlist.n_value);

type = eSymbolTypeData;
}
break;
} break;

case N_FNAME:
// procedure name (f77 kludge): name,,NO_SECT,0,0
Expand Down Expand Up @@ -4453,38 +4412,9 @@ void ObjectFileMachO::ParseSymtab(Symtab &symtab) {
::strstr(symbol_sect_name, "__objc") == symbol_sect_name) {
type = eSymbolTypeRuntime;

if (symbol_name) {
llvm::StringRef symbol_name_ref(symbol_name);
if (symbol_name_ref.starts_with("_OBJC_")) {
llvm::StringRef g_objc_v2_prefix_class(
"_OBJC_CLASS_$_");
llvm::StringRef g_objc_v2_prefix_metaclass(
"_OBJC_METACLASS_$_");
llvm::StringRef g_objc_v2_prefix_ivar(
"_OBJC_IVAR_$_");
if (symbol_name_ref.starts_with(g_objc_v2_prefix_class)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_class.size();
type = eSymbolTypeObjCClass;
demangled_is_synthesized = true;
} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_metaclass)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_metaclass.size();
type = eSymbolTypeObjCMetaClass;
demangled_is_synthesized = true;
} else if (symbol_name_ref.starts_with(
g_objc_v2_prefix_ivar)) {
symbol_name_non_abi_mangled = symbol_name + 1;
symbol_name =
symbol_name + g_objc_v2_prefix_ivar.size();
type = eSymbolTypeObjCIVar;
demangled_is_synthesized = true;
}
}
}
if (TryParseV2ObjCMetadataSymbol(
symbol_name, symbol_name_non_abi_mangled, type))
demangled_is_synthesized = true;
} else if (symbol_sect_name &&
::strstr(symbol_sect_name, "__gcc_except_tab") ==
symbol_sect_name) {
Expand Down
35 changes: 35 additions & 0 deletions lldb/test/Shell/Expr/TestGlobalSymbolObjCConflict.c
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Original file line number Diff line number Diff line change
@@ -0,0 +1,35 @@
// XFAIL: target-windows

// Tests that LLDB correctly parses global symbols
// starting with 'O'. On some platforms (e.g., Darwin)
// C-symbols are prefixed with a '_'. The LLDB Macho-O
// parses handles Objective-C metadata symbols starting
// with '_OBJC' specially. This test ensures that we don't
// lose track of regular global symbols with a '_O' prefix
// in this.

// RUN: %clang_host -c -g -fno-common %s -o %t.o
// RUN: %clang_host %t.o -o %t.out
// RUN: %lldb -b -x %t.out \
// RUN: -o "b 29" \
// RUN: -o "run" \
// RUN: -o "p OglobalVar" \
// RUN: -o "p Oabc" | FileCheck %s

typedef struct {
int a;
} Oabc_t;

Oabc_t Oabc;
int OglobalVar;

int main(int argc, const char *argv[]) {
Oabc.a = 15;
OglobalVar = 10;
return OglobalVar + Oabc.a;
}

// CHECK: (lldb) p OglobalVar
// CHECK: (int) 10
// CHECK: (lldb) p Oabc
// CHECK: (Oabc_t) (a = 15)
2 changes: 1 addition & 1 deletion lldb/test/Shell/lit.cfg.py
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@

# suffixes: A list of file extensions to treat as test files. This is overriden
# by individual lit.local.cfg files in the test subdirectories.
config.suffixes = [".test", ".cpp", ".s", ".m"]
config.suffixes = [".test", ".cpp", ".s", ".m", ".ll", ".c"]

# excludes: A list of directories to exclude from the testsuite. The 'Inputs'
# subdirectories contain auxiliary inputs for various tests in their parent
Expand Down