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When a record type doesn't have complete type debug info, forcefully complete it
to make clang not crashing at places calling `CXXRecordDecl::data()`.
Here's an example when a class has incomplete type debug info.
0x17AB1 | LF_CLASS [size = 48] `v8::Data`
unique name: `.?AVData@v8@@`
vtable: <no type>, base list: <no type>, field list: <no type>
options: forward ref (= 0x17AB1) | has unique name, sizeof 0
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D134066
Files:
lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
lldb/test/Shell/SymbolFile/NativePDB/missing-type.s
Index: lldb/test/Shell/SymbolFile/NativePDB/missing-type.s
===================================================================
--- lldb/test/Shell/SymbolFile/NativePDB/missing-type.s
+++ lldb/test/Shell/SymbolFile/NativePDB/missing-type.s
@@ -1,14 +1,18 @@
# clang-format off
# REQUIRES: lld, x86
-# Test when type index is missing in FieldList.
+# Test when class type is incomplete or type index is missing in FieldList.
# RUN: llvm-mc -triple=x86_64-windows-msvc --filetype=obj %s > %t.obj
-# RUN: lld-link /debug:full /nodefaultlib /entry:main %t.obj /out:%t.exe /base:0x140000000
-# RUN: lldb-test symbols --find=type --name=S %t.exe | FileCheck %s
+# RUN: lld-link /debug:full /nodefaultlib /entry:main %t.obj /out:%t.exe
+# RUN: lldb-test symbols --find=type --name=S %t.exe | FileCheck %s --check-prefix=MISSING-DATA-TYPE
+# RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb -f %t.exe -o "expr a" -o "exit" \
+# RUN: | FileCheck %s --check-prefix=IMCOMPLETE-CLASS
-# CHECK: name = "S", size = 4, compiler_type = {{.*}} struct S {
-# CHECK-NEXT: }
+# MISSING-DATA-TYPE: name = "S", size = 4, compiler_type = {{.*}} struct S {
+# MISSING-DATA-TYPE-NEXT: }
+# IMCOMPLETE-CLASS: (lldb) expr a
+# IMCOMPLETE-CLASS-NEXT: (A) $0 = {}
.text
@@ -43,10 +47,54 @@
.Lfunc_end0:
.seh_endproc
# -- End function
- .section .drectve,"yn"
-.Ltmp25:
+ .bss
+ .globl "?a@@3VA@@A" # @"?a@@3VA@@A"
+ .p2align 2, 0x0
+"?a@@3VA@@A":
+ .zero 4
+ .section .debug$S,"dr"
+ .p2align 2, 0x0
+ .long 4 # Debug section magic
+ .long 241
+ .long .Ltmp3-.Ltmp2 # Subsection size
+.Ltmp2:
+ .short .Ltmp3-.Ltmp6 # Record length
+.Ltmp6:
+ .short 4412 # Record kind: S_COMPILE3
+ .long 1 # Flags and language
+ .short 208 # CPUType
+ .short 16 # Frontend version
+ .short 0
+ .short 0
+ .short 0
+ .short 16000 # Backend version
+ .short 0
+ .short 0
+ .short 0
+ .asciz "clang version 16.0.0" # Null-terminated compiler version string
+ .p2align 2, 0x0
+.Ltmp3:
+ .p2align 2, 0x0
+ .long 241 # Symbol subsection for main
+ .long 0
+ .p2align 2, 0x0
+ .cv_linetable 0, main, .Lfunc_end0
+ .long 241 # Symbol subsection for globals
+ .long .Ltmp19-.Ltmp14 # Subsection size
+.Ltmp14:
+ .short .Ltmp19-.Ltmp16 # Record length
+.Ltmp16:
+ .short 4365 # Record kind: S_GDATA32
+ .long 4103 # Type
+ .secrel32 "?a@@3VA@@A" # DataOffset
+ .secidx "?a@@3VA@@A" # Segment
+ .asciz "a" # Name
+ .p2align 2, 0x0
+
+.Ltmp19:
+ .p2align 2, 0x0
.section .debug$T,"dr"
- .p2align 2
+ .p2align 2, 0x0
.long 4 # Debug section magic
# Pointer (0x1000)
.short 0xa # Record length
@@ -87,6 +135,7 @@
.short 0x0 # SizeOf
.asciz "S" # Name
.asciz ".?AUS@@" # LinkageName
+ # Test when a class member has missing type info.
# FieldList (0x1005)
.short 0xe # Record length
.short 0x1203 # Record kind: LF_FIELDLIST
@@ -106,3 +155,15 @@
.short 0x4 # SizeOf
.asciz "S" # Name
.asciz ".?AUS@@" # LinkageName
+ # Test when class doesn't have full type info (forward reference to itself).
+ # Class (0x1007)
+ .short 0x1e # Record length
+ .short 0x1504 # Record kind: LF_CLASS
+ .short 0x1 # MemberCount
+ .short 0x280 # Properties ( ForwardReference (0x80) | HasUniqueName (0x200) )
+ .long 0x0 # FieldList: <field list>
+ .long 0x0 # DerivedFrom
+ .long 0x0 # VShape
+ .short 0x0 # SizeOf
+ .asciz "A" # Name
+ .asciz ".?AVA@@" # LinkageName
Index: lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
+++ lldb/source/Plugins/SymbolFile/NativePDB/PdbAstBuilder.cpp
@@ -666,9 +666,21 @@
cvt = m_index.tpi().getType(best_ti.index);
lldbassert(IsTagRecord(cvt));
+ CompilerType ct = ToCompilerType(tag_qt);
if (IsForwardRefUdt(cvt)) {
// If we can't find a full decl for this forward ref anywhere in the debug
- // info, then we have no way to complete it.
+ // info, then we have no way to complete it, just forcefully marking it as
+ // completed. Otherwise, clang will crash due to missing DefinitionData when
+ // trying to import AST.
+ if (!ct.GetCompleteType()) {
+ bool started = TypeSystemClang::StartTagDeclarationDefinition(ct);
+ lldbassert(started && "Unable to start a class type definition.");
+ TypeSystemClang::CompleteTagDeclarationDefinition(ct);
+ if (TypeSystemClang::IsCXXClassType(ct)) {
+ auto &ts = llvm::cast<TypeSystemClang>(*ct.GetTypeSystem());
+ ts.GetMetadata(&tag)->SetIsForcefullyCompleted();
+ }
+ }
return false;
}
@@ -683,7 +695,6 @@
// Visit all members of this class, then perform any finalization necessary
// to complete the class.
- CompilerType ct = ToCompilerType(tag_qt);
UdtRecordCompleter completer(best_ti, ct, tag, *this, m_index,
m_cxx_record_map);
llvm::Error error =
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