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[lldb][MachO] Fix inspection of global variables that start with 'O' #161521

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Merged
merged 4 commits into from
Oct 1, 2025
Merged

[lldb][MachO] Fix inspection of global variables that start with 'O' #161521

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f4e7b75
[lldb][test] Allow '.c' files to be used as shell tests
Michael137 Oct 1, 2025
24007ee
[lldb][MachO] Fix inspection of global variables that start with 'O'
Michael137 Oct 1, 2025
87cd9ad
Merge branch 'main' into lldb/fix-global-symbol-objc-check
Michael137 Oct 1, 2025
980ca0b
fixup! fix breakpoint location
Michael137 Oct 1, 2025
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90 changes: 42 additions & 48 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 @@ -2805,32 +2805,29 @@ 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;
}
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;
} else {
if (nlist.n_value != 0)
symbol_section = section_info.GetSection(
Expand Down Expand Up @@ -3652,7 +3649,7 @@ 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 @@ -3668,33 +3665,30 @@ 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;
}
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;
} 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
33 changes: 33 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 +1,33 @@
// 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 17" \
// 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)
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