Re-land r313825: "[IR] Add llvm.dbg.addr, a control-dependent version of llvm.dbg.declare"

The fix is to avoid invalidating our insertion point in
replaceDbgDeclare:
     Builder.insertDeclare(NewAddress, DIVar, DIExpr, Loc, InsertBefore);
+    if (DII == InsertBefore)
+      InsertBefore = &*std::next(InsertBefore->getIterator());
     DII->eraseFromParent();

I had to write a unit tests for this instead of a lit test because the
use list order matters in order to trigger the bug.

The reduced C test case for this was:
  void useit(int*);
  static inline void inlineme() {
    int x[2];
    useit(x);
  }
  void f() {
    inlineme();
    inlineme();
  }

llvm-svn: 313905

1 files changed, 67 insertions, 0 deletions

diff --git a/llvm/test/DebugInfo/X86/dbg-addr.ll b/llvm/test/DebugInfo/X86/dbg-addr.ll
new file mode 100644
index 00000000000..ffd0f77ebb7
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/dbg-addr.ll
@@ -0,0 +1,67 @@
+; RUN: llc %s -o %t.s
+; RUN: llvm-mc -triple x86_64--linux %t.s -filetype=obj -o %t.o
+; RUN: FileCheck < %t.s %s
+; RUN: llvm-dwarfdump %t.o | FileCheck %s --check-prefix=DWARF
+
+; Unlike dbg.declare, dbg.addr should be lowered to DBG_VALUE instructions. It
+; is control-dependent.
+
+; CHECK-LABEL: use_dbg_addr:
+; CHECK: #DEBUG_VALUE: use_dbg_addr:o <- [%RSP+0]
+
+; FIXME: Avoid the use of a single-location location list and use
+; DW_AT_start_offset instead.
+
+; DWARF: DW_TAG_variable
+; DWARF-NEXT:              DW_AT_location (0x00000000
+; DWARF-NEXT:                          0x{{.*}} - 0x{{.*}}: DW_OP_breg7 RSP+0)
+; DWARF-NEXT:              DW_AT_name ("o")
+
+
+; ModuleID = 't.c'
+source_filename = "t.c"
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--linux"
+
+%struct.Foo = type { i32 }
+
+; Function Attrs: noinline nounwind uwtable
+define void @use_dbg_addr() #0 !dbg !7 {
+entry:
+  %o = alloca %struct.Foo, align 4
+  call void @llvm.dbg.addr(metadata %struct.Foo* %o, metadata !10, metadata !15), !dbg !16
+  call void @escape_foo(%struct.Foo* %o), !dbg !17
+  ret void, !dbg !18
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.addr(metadata, metadata, metadata) #1
+
+declare void @escape_foo(%struct.Foo*)
+
+attributes #0 = { noinline nounwind uwtable }
+attributes #1 = { nounwind readnone speculatable }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+!llvm.ident = !{!6}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "t.c", directory: "C:\5Csrc\5Cllvm-project\5Cbuild")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 6.0.0 "}
+!7 = distinct !DISubprogram(name: "use_dbg_addr", scope: !1, file: !1, line: 3, type: !8, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null}
+!10 = !DILocalVariable(name: "o", scope: !7, file: !1, line: 4, type: !11)
+!11 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", file: !1, line: 1, size: 32, elements: !12)
+!12 = !{!13}
+!13 = !DIDerivedType(tag: DW_TAG_member, name: "x", scope: !11, file: !1, line: 1, baseType: !14, size: 32)
+!14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!15 = !DIExpression()
+!16 = !DILocation(line: 4, column: 14, scope: !7)
+!17 = !DILocation(line: 5, column: 3, scope: !7)
+!18 = !DILocation(line: 6, column: 1, scope: !7)