[DIBuilder] Make createReferenceType take size and align

Summary: Since we're passing references to dbg.value as pointers,
we need to have the frontend properly declare their sizes and
alignments (as it already does for regular pointers) in preparation
for my upcoming patch to have the verifer check that the sizes agree.

Also augment the backend logic that skips actually emitting this
information into DWARF such that it also handles reference types.

Reviewers: aprantl, dexonsmith, dblaikie

Subscribers: dblaikie, llvm-commits

Differential Revision: http://reviews.llvm.org/D14275

llvm-svn: 253186

4 files changed, 56 insertions, 4 deletions

diff --git a/llvm/include/llvm/IR/DIBuilder.h b/llvm/include/llvm/IR/DIBuilder.h
index fa8b7a78b92..aeec3954115 100644
--- a/llvm/include/llvm/IR/DIBuilder.h
+++ b/llvm/include/llvm/IR/DIBuilder.h
@@ -158,7 +158,9 @@ namespace llvm {
 
     /// Create debugging information entry for a c++
     /// style reference or rvalue reference type.
-    DIDerivedType *createReferenceType(unsigned Tag, DIType *RTy);
+    DIDerivedType *createReferenceType(unsigned Tag, DIType *RTy,
+                                       uint64_t SizeInBits = 0,
+                                       uint64_t AlignInBits = 0);
 
     /// Create debugging information entry for a typedef.
     /// \param Ty          Original type.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index c441a67a5d7..d75fea5d8c8 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -853,7 +853,9 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy) {
 
   // Add size if non-zero (derived types might be zero-sized.)
   if (Size && Tag != dwarf::DW_TAG_pointer_type
-           && Tag != dwarf::DW_TAG_ptr_to_member_type)
+           && Tag != dwarf::DW_TAG_ptr_to_member_type
+           && Tag != dwarf::DW_TAG_reference_type
+           && Tag != dwarf::DW_TAG_rvalue_reference_type)
     addUInt(Buffer, dwarf::DW_AT_byte_size, None, Size);
 
   if (Tag == dwarf::DW_TAG_ptr_to_member_type)
diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 7fc0652bf65..09b540350c2 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -255,10 +255,12 @@ DIDerivedType *DIBuilder::createMemberPointerType(DIType *PointeeTy,
                             DITypeRef::get(Base));
 }
 
-DIDerivedType *DIBuilder::createReferenceType(unsigned Tag, DIType *RTy) {
+DIDerivedType *DIBuilder::createReferenceType(unsigned Tag, DIType *RTy,
+                                              uint64_t SizeInBits,
+                                              uint64_t AlignInBits) {
   assert(RTy && "Unable to create reference type");
   return DIDerivedType::get(VMContext, Tag, "", nullptr, 0, nullptr,
-                            DITypeRef::get(RTy), 0, 0, 0, 0);
+                            DITypeRef::get(RTy), SizeInBits, AlignInBits, 0, 0);
 }
 
 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
diff --git a/llvm/test/DebugInfo/Generic/ptrsize.ll b/llvm/test/DebugInfo/Generic/ptrsize.ll
new file mode 100755
index 00000000000..694aa0bbf3e
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/ptrsize.ll
@@ -0,0 +1,46 @@
+; REQUIRES: object-emission
+
+; RUN: %llc_dwarf -O0 -filetype=obj < %s > %t
+; RUN: llvm-dwarfdump %t | FileCheck %s
+
+; Check that pointers and references get emitted without size information in
+; DWARF, even if they are so specified in the IR
+
+; CHECK: 0x[[O1:[0-9a-f]+]]:   DW_TAG_pointer_type
+; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
+; CHECK-NOT: DW_AT_byte_size
+; CHECK: 0x[[O2:[0-9a-f]+]]:   DW_TAG_
+
+; CHECK: 0x[[O3:[0-9a-f]+]]:   DW_TAG_reference_type
+; CHECK-NEXT: DW_AT_type [DW_FORM_ref4]
+; CHECK-NOT: DW_AT_byte_size
+
+define i32 @foo() !dbg !4 {
+entry:
+  ret i32 0, !dbg !13
+}
+
+define i32 @bar() !dbg !5 {
+entry:
+  ret i32 0, !dbg !13
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!11, !12}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: 0, enums: !2, retainedTypes: !2, subprograms: !3, globals: !2, imports: !2)
+!1 = !DIFile(filename: "dwarf-test.c", directory: "test")
+!2 = !{}
+!3 = !{!4, !5}
+!4 = distinct !DISubprogram(name: "foo", scope: !0, file: !1, line: 6, type: !6, isLocal: false, isDefinition: true, scopeLine: 6, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
+!5 = distinct !DISubprogram(name: "bar", scope: !0, file: !1, line: 6, type: !15, isLocal: false, isDefinition: true, scopeLine: 6, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
+!6 = !DISubroutineType(types: !7)
+!7 = !{!9}
+!8 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!9 = !DIDerivedType(tag: DW_TAG_pointer_type, scope: !0, baseType: !8, size: 64, align: 64)
+!10 = !DIDerivedType(tag: DW_TAG_reference_type, scope: !0, baseType: !8, size: 64, align: 64)
+!11 = !{i32 2, !"Dwarf Version", i32 3}
+!12 = !{i32 1, !"Debug Info Version", i32 3}
+!13 = !DILocation(line: 7, scope: !4)
+!14 = !{!10}
+!15 = !DISubroutineType(types: !14)