[Lldb-commits] [lldb] [lldb][NativePDB] Handle `S_DEFRANGE_REGISTER_REL_INDIR` (PR #190336)
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Fri Apr 3 04:55:55 PDT 2026
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Nerixyz (Nerixyz)
<details>
<summary>Changes</summary>
Since #<!-- -->189401, LLVM and Clang generate `S_DEFRANGE_REGISTER_REL_INDIR` for indirect locations. This adds support in LLDB.
The offset added after dereferencing is signed here - unlike in `S_REGREL32_INDIR` (at least that's the assumption). So I updated `MakeRegisterBasedIndirectLocationExpressionInternal` to handle the signedness. This is the reason the MSVC test was changed here.
I didn't find a test case where LLVM emits the record with the `VFRAME` register. Other than that, the clang test is similar to the MSVC one except that the locations are slightly different.
---
Full diff: https://github.com/llvm/llvm-project/pull/190336.diff
5 Files Affected:
- (modified) lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.cpp (+27-1)
- (modified) lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.h (+4)
- (modified) lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp (+31)
- (added) lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-clang.test (+45)
- (modified) lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-msvc.test (+2-2)
``````````diff
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.cpp
index 0b7e2e31c1414..fb37a8138d88d 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.cpp
@@ -166,8 +166,9 @@ static bool MakeRegisterBasedIndirectLocationExpressionInternal(
return false;
stream.PutHex8(llvm::dwarf::DW_OP_deref);
- stream.PutHex8(llvm::dwarf::DW_OP_plus_uconst);
+ stream.PutHex8(llvm::dwarf::DW_OP_consts);
stream.PutSLEB128(offset);
+ stream.PutHex8(llvm::dwarf::DW_OP_plus);
return true;
}
@@ -229,6 +230,31 @@ DWARFExpression lldb_private::npdb::MakeVFrameRelLocationExpression(
});
}
+DWARFExpression lldb_private::npdb::MakeVFrameRelIndirLocationExpression(
+ llvm::StringRef fpo_program, int32_t offset, int32_t offset_in_udt,
+ lldb::ModuleSP module) {
+ return MakeLocationExpressionInternal(
+ module, [&](Stream &stream, RegisterKind ®ister_kind) -> bool {
+ const ArchSpec &architecture = module->GetArchitecture();
+
+ if (!EmitVFrameEvaluationDWARFExpression(
+ fpo_program, architecture.GetMachine(), stream))
+ return false;
+
+ stream.PutHex8(llvm::dwarf::DW_OP_consts);
+ stream.PutSLEB128(offset);
+ stream.PutHex8(llvm::dwarf::DW_OP_plus);
+ stream.PutHex8(llvm::dwarf::DW_OP_deref);
+ stream.PutHex8(llvm::dwarf::DW_OP_consts);
+ stream.PutSLEB128(offset_in_udt);
+ stream.PutHex8(llvm::dwarf::DW_OP_plus);
+
+ register_kind = eRegisterKindLLDB;
+
+ return true;
+ });
+}
+
DWARFExpression lldb_private::npdb::MakeGlobalLocationExpression(
uint16_t section, uint32_t offset, ModuleSP module) {
assert(section > 0);
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.h b/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.h
index 81a47d6dad0f2..e1478db6ce9f6 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.h
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/DWARFLocationExpression.h
@@ -47,6 +47,10 @@ MakeRegRelIndirLocationExpression(llvm::codeview::RegisterId reg,
DWARFExpression MakeVFrameRelLocationExpression(llvm::StringRef fpo_program,
int32_t offset,
lldb::ModuleSP module);
+DWARFExpression
+MakeVFrameRelIndirLocationExpression(llvm::StringRef fpo_program,
+ int32_t offset, int32_t offset_in_udt,
+ lldb::ModuleSP module);
DWARFExpression MakeGlobalLocationExpression(uint16_t section, uint32_t offset,
lldb::ModuleSP module);
llvm::Expected<DWARFExpression> MakeConstantLocationExpression(
diff --git a/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp b/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp
index a90ca32fffac7..5860d90eca689 100644
--- a/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp
+++ b/lldb/source/Plugins/SymbolFile/NativePDB/PdbUtil.cpp
@@ -888,6 +888,37 @@ VariableInfo lldb_private::npdb::GetVariableLocationInfo(
AddDwarfRange(location_map, expr, raw_ranges);
break;
}
+ case S_DEFRANGE_REGISTER_REL_INDIR: {
+ DefRangeRegisterRelIndirSym loc(
+ SymbolRecordKind::DefRangeRegisterRelIndirSym);
+ if (llvm::Error error =
+ SymbolDeserializer::deserializeAs<DefRangeRegisterRelIndirSym>(
+ loc_specifier_cvs, loc)) {
+ llvm::consumeError(std::move(error));
+ return result;
+ }
+ Variable::RangeList raw_ranges =
+ MakeRangeList(index, loc.Range, loc.Gaps);
+ RegisterId reg_id = (RegisterId)(uint16_t)loc.Hdr.Register;
+ DWARFExpression expr;
+ if (reg_id == RegisterId::VFRAME) {
+ llvm::StringRef program;
+ if (GetFrameDataProgram(index, raw_ranges, program))
+ expr = MakeVFrameRelIndirLocationExpression(
+ program, loc.Hdr.BasePointerOffset, loc.Hdr.OffsetInUdt,
+ module);
+ else {
+ // invalid variable
+ }
+ } else {
+ expr = MakeRegRelIndirLocationExpression(
+ reg_id, loc.Hdr.BasePointerOffset, loc.Hdr.OffsetInUdt, module);
+ }
+ // FIXME: If it's UDT, we need to know the size of the value in byte.
+ if (!loc.hasSpilledUDTMember())
+ AddDwarfRange(location_map, expr, raw_ranges);
+ break;
+ }
case S_DEFRANGE_SUBFIELD_REGISTER: {
DefRangeSubfieldRegisterSym loc(
SymbolRecordKind::DefRangeSubfieldRegisterSym);
diff --git a/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-clang.test b/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-clang.test
new file mode 100644
index 0000000000000..254015ff198fa
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-clang.test
@@ -0,0 +1,45 @@
+# REQUIRES: lld, target-windows
+
+# Test that LLDB can show variables introduced in C++ 17 structured bindings
+# when compiled with clang-cl.
+
+# RUN: split-file %s %t
+
+# RUN: %build --compiler=clang-cl --arch=64 --std=c++17 --nodefaultlib -o %t.exe -- %t/main.cpp
+# RUN: lldb-test symbols %t.exe | FileCheck %s --check-prefix=SYMBOLS
+# RUN: %lldb -f %t.exe -s %t/commands.input | FileCheck %s --check-prefix=LLDB
+
+#--- main.cpp
+
+struct Foo { int a; int b; };
+
+int main() {
+ Foo f{1, 2};
+
+ auto&[a, b] = f;
+ return a + b; // break here
+}
+
+#--- commands.input
+
+br set -p "break here"
+r
+v f
+v a
+v b
+q
+
+# SYMBOLS: Function{{.*}}, demangled = main, type =
+# SYMBOLS-NEXT: Block{{.*}}, ranges =
+# SYMBOLS-DAG: Variable{{.*}}, name = "f", type = {{.*}} (Foo), scope = local, location =
+# SYMBOLS-DAG: Variable{{.*}}, name = "a", type = {{.*}} (int), scope = local, location = 0x00000000:
+# SYMBOLS-NEXT: [{{.*}}): DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_consts +0, DW_OP_plus
+# SYMBOLS-DAG: Variable{{.*}}, name = "b", type = {{.*}} (int), scope = local, location = 0x00000000:
+# SYMBOLS-NEXT: [{{.*}}): DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_consts {{[+-][0-9]+}}, DW_OP_plus
+
+# LLDB: (lldb) v f
+# LLDB-NEXT: (Foo) f = (a = 1, b = 2)
+# LLDB-NEXT: (lldb) v a
+# LLDB-NEXT: (int) a = 1
+# LLDB-NEXT: (lldb) v b
+# LLDB-NEXT: (int) b = 2
diff --git a/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-msvc.test b/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-msvc.test
index ebe6cceda7ea6..a4d162248e6d2 100644
--- a/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-msvc.test
+++ b/lldb/test/Shell/SymbolFile/NativePDB/structured-bindings-msvc.test
@@ -32,8 +32,8 @@ q
# SYMBOLS: Function{{.*}}, demangled = main, type =
# SYMBOLS-NEXT: Block{{.*}}, ranges =
# SYMBOLS-NEXT: Variable{{.*}}, name = "f", type = {{.*}} (Foo), scope = local, location =
-# SYMBOLS-NEXT: Variable{{.*}}, name = "b", type = {{.*}} (int), scope = local, location = DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_plus_uconst 0x{{[0-9]+}}
-# SYMBOLS-NEXT: Variable{{.*}}, name = "a", type = {{.*}} (int), scope = local, location = DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_plus_uconst 0x0
+# SYMBOLS-NEXT: Variable{{.*}}, name = "b", type = {{.*}} (int), scope = local, location = DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_consts {{[+-][0-9]+}}, DW_OP_plus
+# SYMBOLS-NEXT: Variable{{.*}}, name = "a", type = {{.*}} (int), scope = local, location = DW_OP_breg{{.*}}, DW_OP_deref, DW_OP_consts +0, DW_OP_plus
# LLDB: (lldb) v f
# LLDB-NEXT: (Foo) f = (a = 1, b = 2)
``````````
</details>
https://github.com/llvm/llvm-project/pull/190336
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