[codeview] support more DW_OPs for more complete debug info

Summary:
Some variables show up in Visual Studio as "optimized out" even in -O0
-Od builds. This change fixes two issues that would cause this to
happen. The first issue is that not all DIExpressions we generate were
recognized by the CodeView writer. This has been addressed by adding
support for DW_OP_constu, DW_OP_minus, and DW_OP_plus. The second
issue is that we had no way to encode DW_OP_deref in CodeView. We get
around that by changinge the type we encode in the debug info to be
a reference to the type in the source code.

This fixes PR34261.

Reviewers: aprantl, rnk, zturner

Reviewed By: rnk

Subscribers: mgorny, llvm-commits, aprantl, hiraditya

Differential Revision: https://reviews.llvm.org/D36907

llvm-svn: 311957

2 files changed, 70 insertions, 17 deletions

diff --git a/llvm/test/DebugInfo/COFF/pieces.ll b/llvm/test/DebugInfo/COFF/pieces.ll
index 6d363cf5443..9a90300bb99 100644
--- a/llvm/test/DebugInfo/COFF/pieces.ll
+++ b/llvm/test/DebugInfo/COFF/pieces.ll
@@ -179,8 +179,7 @@
 ; ASM:        .asciz  "nested"                # Function name
 ; ASM:        .short  4414                    # Record kind: S_LOCAL
 ; ASM:        .asciz  "o"
-; FIXME: We should have a .cv_def_range for 'o', but we don't yet.
-; ASM-NOT:    .cv_def_range
+; ASM:        .cv_def_range    .Lfunc_begin3 .Lfunc_end3, "E\021J\001\000\000\000\000\000\000"
 ; ASM:        .short  4414                    # Record kind: S_LOCAL
 ; ASM:        .asciz  "p"
 ; ASM:        .cv_def_range    [[p_start]] .Lfunc_end3, "C\021\021\000\000\000\004\000\000\000"
@@ -190,8 +189,17 @@
 ; OBJ:         DisplayName: nested
 ; OBJ:       }
 ; OBJ:       LocalSym {
+; OBJ:         Type: Nested&
 ; OBJ:         VarName: o
 ; OBJ:       }
+; OBJ:       DefRangeRegisterRelSym {
+; OBJ:         BaseRegister: 330
+; OBJ:         HasSpilledUDTMember: No
+; OBJ:         OffsetInParent: 0
+; OBJ:         BasePointerOffset: 0
+; OBJ:         LocalVariableAddrRange {
+; OBJ:         }
+; OBJ:       }
 ; OBJ:       LocalSym {
 ; OBJ:         VarName: p
 ; OBJ:       }
diff --git a/llvm/test/DebugInfo/COFF/types-array-advanced.ll b/llvm/test/DebugInfo/COFF/types-array-advanced.ll
index d8985504e32..69da2b53993 100644
--- a/llvm/test/DebugInfo/COFF/types-array-advanced.ll
+++ b/llvm/test/DebugInfo/COFF/types-array-advanced.ll
@@ -50,28 +50,40 @@
 ; CHECK:     SizeOf: 4
 ; CHECK:     Name: 
 ; CHECK:   }
-; CHECK:   Array (0x1004) {
+; CHECK:   Pointer (0x1004) {
+; CHECK:     TypeLeafKind: LF_POINTER (0x1002)
+; CHECK:     PointeeType: 0x1003
+; CHECK:     PointerAttributes: 0x2A
+; CHECK:     PtrType: Near32 (0xA)
+; CHECK:     PtrMode: LValueReference (0x1)
+; CHECK:     IsFlat: 0
+; CHECK:     IsConst: 0
+; CHECK:     IsVolatile: 0
+; CHECK:     IsUnaligned: 0
+; CHECK:     SizeOf: 0
+; CHECK:   }
+; CHECK:   Array (0x1005) {
 ; CHECK:     TypeLeafKind: LF_ARRAY (0x1503)
 ; CHECK:     ElementType: char (0x70)
 ; CHECK:     IndexType: unsigned long (0x22)
 ; CHECK:     SizeOf: 7
 ; CHECK:     Name: 
 ; CHECK:   }
-; CHECK:   Array (0x1005) {
+; CHECK:   Array (0x1006) {
 ; CHECK:     TypeLeafKind: LF_ARRAY (0x1503)
-; CHECK:     ElementType: 0x1004
+; CHECK:     ElementType: 0x1005
 ; CHECK:     IndexType: unsigned long (0x22)
 ; CHECK:     SizeOf: 35
 ; CHECK:     Name: 
 ; CHECK:   }
-; CHECK:   Array (0x1006) {
+; CHECK:   Array (0x1007) {
 ; CHECK:     TypeLeafKind: LF_ARRAY (0x1503)
-; CHECK:     ElementType: 0x1005
+; CHECK:     ElementType: 0x1006
 ; CHECK:     IndexType: unsigned long (0x22)
 ; CHECK:     SizeOf: 70
 ; CHECK:     Name: 
 ; CHECK:   }
-; CHECK:   Struct (0x1007) {
+; CHECK:   Struct (0x1008) {
 ; CHECK:     TypeLeafKind: LF_STRUCTURE (0x1505)
 ; CHECK:     MemberCount: 0
 ; CHECK:     Properties [ (0x280)
@@ -85,16 +97,16 @@
 ; CHECK:     Name: incomplete_struct
 ; CHECK:     LinkageName: .?AUincomplete_struct@@
 ; CHECK:   }
-; CHECK:   Array (0x1008) {
+; CHECK:   Array (0x1009) {
 ; CHECK:     TypeLeafKind: LF_ARRAY (0x1503)
-; CHECK:     ElementType: incomplete_struct (0x1007)
+; CHECK:     ElementType: incomplete_struct (0x1008)
 ; CHECK:     IndexType: unsigned long (0x22)
 ; CHECK:     SizeOf: 12
 ; CHECK:     Name: 
 ; CHECK:   }
-; CHECK:   Pointer (0x1009) {
+; CHECK:   Pointer (0x100A) {
 ; CHECK:     TypeLeafKind: LF_POINTER (0x1002)
-; CHECK:     PointeeType: 0x1008
+; CHECK:     PointeeType: 0x1009
 ; CHECK:     PointerAttributes: 0x800A
 ; CHECK:     PtrType: Near32 (0xA)
 ; CHECK:     PtrMode: Pointer (0x0)
@@ -104,8 +116,41 @@
 ; CHECK:     IsUnaligned: 0
 ; CHECK:     SizeOf: 4
 ; CHECK:   }
-;
-; CHECK:   Modifier (0x100E) {
+; CHECK:   FieldList (0x100B) {
+; CHECK:     TypeLeafKind: LF_FIELDLIST (0x1203)
+; CHECK:     DataMember {
+; CHECK:       TypeLeafKind: LF_MEMBER (0x150D)
+; CHECK:       AccessSpecifier: Public (0x3)
+; CHECK:       Type: int (0x74)
+; CHECK:       FieldOffset: 0x0
+; CHECK:       Name: s1
+; CHECK:     }
+; CHECK:   }
+; CHECK:   Struct (0x100C) {
+; CHECK:     TypeLeafKind: LF_STRUCTURE (0x1505)
+; CHECK:     MemberCount: 1
+; CHECK:     Properties [ (0x200)
+; CHECK:       HasUniqueName (0x200)
+; CHECK:     ]
+; CHECK:     FieldList: <field list> (0x100B)
+; CHECK:     DerivedFrom: 0x0
+; CHECK:     VShape: 0x0
+; CHECK:     SizeOf: 4
+; CHECK:     Name: incomplete_struct
+; CHECK:     LinkageName: .?AUincomplete_struct@@
+; CHECK:   }
+; CHECK:   StringId (0x100D) {
+; CHECK:     TypeLeafKind: LF_STRING_ID (0x1605)
+; CHECK:     Id: 0x0
+; CHECK:     StringData: \t.cpp
+; CHECK:   }
+; CHECK:   UdtSourceLine (0x100E) {
+; CHECK:     TypeLeafKind: LF_UDT_SRC_LINE (0x1606)
+; CHECK:     UDT: incomplete_struct (0x100C)
+; CHECK:     SourceFile: \t.cpp (0x100D)
+; CHECK:     LineNumber: 4
+; CHECK:   }
+; CHECK:   Modifier (0x100F) {
 ; CHECK:     TypeLeafKind: LF_MODIFIER (0x1001)
 ; CHECK:     ModifiedType: int (0x74)
 ; CHECK:     Modifiers [ (0x3)
@@ -113,12 +158,12 @@
 ; CHECK:       Volatile (0x2)
 ; CHECK:     ]
 ; CHECK:   }
-; CHECK:   Array (0x100F) {
+; CHECK:   Array (0x1010) {
 ; CHECK:     TypeLeafKind: LF_ARRAY (0x1503)
-; CHECK:     ElementType: const volatile int (0x100E)
+; CHECK:     ElementType: const volatile int (0x100F)
 ; CHECK:     IndexType: unsigned long (0x22)
 ; CHECK:     SizeOf: 16
-; CHECK:     Name:
+; CHECK:     Name: 
 ; CHECK:   }
 ; CHECK: ]