[DWARF5]Addition of alignment atrribute in typedef DIE.

This patch, adds support for DW_AT_alignment[DWARF5] attribute, to be emitted with typdef DIE.
When explicit alignment is specified.

Patch by Awanish Pandey <Awanish.Pandey@amd.com>

Reviewers: aprantl, dblaikie, jini.susan.george, SouraVX, alok,
deadalinx

Differential Revision: https://reviews.llvm.org/D70111

include/llvm-c/DebugInfo.h

@@ -875,7 +875,7 @@ LLVMMetadataRef
 LLVMDIBuilderCreateTypedef(LLVMDIBuilderRef Builder, LLVMMetadataRef Type,
                            const char *Name, size_t NameLen,
                            LLVMMetadataRef File, unsigned LineNo,
-                           LLVMMetadataRef Scope);
+                           LLVMMetadataRef Scope, uint32_t AlignInBits);
 
 /**
  * Create debugging information entry to establish inheritance relationship

include/llvm/IR/DIBuilder.h

@@ -237,8 +237,10 @@ namespace llvm {
     /// \param File        File where this type is defined.
     /// \param LineNo      Line number.
     /// \param Context     The surrounding context for the typedef.
+    /// \param AlignInBits Alignment. (Optional)
     DIDerivedType *createTypedef(DIType *Ty, StringRef Name, DIFile *File,
-                                 unsigned LineNo, DIScope *Context);
+                                 unsigned LineNo, DIScope *Context,
+                                 Optional<unsigned> AlignInBits = {});
 
     /// Create debugging information entry for a 'friend'.
     DIDerivedType *createFriend(DIType *Ty, DIType *FriendTy);

lib/CodeGen/AsmPrinter/DwarfUnit.cpp

@@ -800,6 +800,15 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, const DIDerivedType *DTy) {
   if (!Name.empty())
     addString(Buffer, dwarf::DW_AT_name, Name);
 
+  // If alignment is specified for a typedef , create and insert DW_AT_alignment
+  // attribute in DW_TAG_typedef DIE.
+  if (Tag == dwarf::DW_TAG_typedef && DD->getDwarfVersion() >= 5) {
+    uint32_t AlignInBytes = DTy->getAlignInBytes();
+    if (AlignInBytes > 0)
+      addUInt(Buffer, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata,
+              AlignInBytes);
+  }
+
   // 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

lib/IR/DIBuilder.cpp

@@ -306,9 +306,11 @@ DIDerivedType *DIBuilder::createReferenceType(
 
 DIDerivedType *DIBuilder::createTypedef(DIType *Ty, StringRef Name,
                                         DIFile *File, unsigned LineNo,
-                                        DIScope *Context) {
+                                        DIScope *Context,
+                                        Optional<unsigned> AlignInBits) {
   return DIDerivedType::get(VMContext, dwarf::DW_TAG_typedef, Name, File,
-                            LineNo, getNonCompileUnitScope(Context), Ty, 0, 0,
+                            LineNo, getNonCompileUnitScope(Context), Ty, 0,
+                            AlignInBits.hasValue() ? AlignInBits.getValue() : 0,
                             0, None, DINode::FlagZero);
 }
 

lib/IR/DebugInfo.cpp

@@ -1108,11 +1108,10 @@ LLVMMetadataRef
 LLVMDIBuilderCreateTypedef(LLVMDIBuilderRef Builder, LLVMMetadataRef Type,
                            const char *Name, size_t NameLen,
                            LLVMMetadataRef File, unsigned LineNo,
-                           LLVMMetadataRef Scope) {
+                           LLVMMetadataRef Scope, uint32_t AlignInBits) {
   return wrap(unwrap(Builder)->createTypedef(
-                  unwrapDI<DIType>(Type), {Name, NameLen},
+      unwrapDI<DIType>(Type), {Name, NameLen}, unwrapDI<DIFile>(File), LineNo,
-                  unwrapDI<DIFile>(File), LineNo,
+      unwrapDI<DIScope>(Scope), AlignInBits));
-                  unwrapDI<DIScope>(Scope)));
 }
 
 LLVMMetadataRef

test/DebugInfo/X86/debug-info-template-align.ll

@@ -0,0 +1,63 @@
+; RUN: llc %s -filetype=obj -o - | llvm-dwarfdump -v - | FileCheck %s
+
+; C++ source to regenerate:
+
+;typedef char  __attribute__((__aligned__(64))) alchar;
+
+;int main(){
+;    alchar newChar;
+;}
+; $ clang++ -O0 -g -gdwarf-5 debug-info-template-align.cpp -c
+
+; CHECK: .debug_abbrev contents:
+
+; CHECK: [5] DW_TAG_typedef  DW_CHILDREN_no
+; CHECK:  DW_AT_alignment DW_FORM_udata
+
+; CHECK: .debug_info contents:
+
+;CHECK: DW_TAG_typedef [5]
+;CHECK: DW_AT_name {{.*}} "alchar"
+;CHECK-NEXT: DW_AT_alignment [DW_FORM_udata] (64)
+
+
+; ModuleID = '/dir/test.cpp'
+source_filename = "/dir/test.cpp"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline norecurse nounwind optnone uwtable
+define dso_local i32 @main() #0 !dbg !7 {
+entry:
+  %newChar = alloca i8, align 64
+  call void @llvm.dbg.declare(metadata i8* %newChar, metadata !12, metadata !DIExpression()), !dbg !15
+  ret i32 0, !dbg !16
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+attributes #0 = { noinline norecurse nounwind optnone uwtable }
+attributes #1 = { nounwind readnone speculatable willreturn }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang version 10.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "/dir/test.cpp", directory: "/home/awpandey/tools/llvm/test/DebugInfo", checksumkind: CSK_MD5, checksum: "872e252efdfcb9480b4bfaf8437f58ab")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 5}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 10.0.0 "}
+!7 = distinct !DISubprogram(name: "main", scope: !8, file: !8, line: 12, type: !9, scopeLine: 12, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DIFile(filename: "test.cpp", directory: "/dir", checksumkind: CSK_MD5, checksum: "872e252efdfcb9480b4bfaf8437f58ab")
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocalVariable(name: "newChar", scope: !7, file: !8, line: 13, type: !13)
+!13 = !DIDerivedType(tag: DW_TAG_typedef, name: "alchar", file: !8, line: 10, baseType: !14, align: 512)
+!14 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
+!15 = !DILocation(line: 13, column: 10, scope: !7)
+!16 = !DILocation(line: 14, column: 1, scope: !7)

tools/llvm-c-test/debuginfo.c

@@ -69,7 +69,7 @@ int llvm_test_dibuilder(void) {
   LLVMMetadataRef Int64Ty =
       LLVMDIBuilderCreateBasicType(DIB, "Int64", 5, 64, 0, LLVMDIFlagZero);
   LLVMMetadataRef Int64TypeDef =
-    LLVMDIBuilderCreateTypedef(DIB, Int64Ty, "int64_t", 7, File, 42, File);
+      LLVMDIBuilderCreateTypedef(DIB, Int64Ty, "int64_t", 7, File, 42, File, 0);
 
   LLVMMetadataRef GlobalVarValueExpr =
       LLVMDIBuilderCreateConstantValueExpression(DIB, 0);