[PATCH] D79306: llvm rejects DWARF operator DW_OP_push_object_address.

[Alok Kumar Sharma via Phabricator via llvm-commits]

alok created this revision.
alok added reviewers: aprantl, probinson, dblaikie, jmorse, vsk, dstenb, jini.susan.george, SouraVX.
alok added projects: debug-info, LLVM.
Herald added subscribers: llvm-commits, ormris, hiraditya.
Herald added a reviewer: DavidTruby.

llvm rejects DWARF operator DW_OP_push_object_address.
This DWARF operator is needed for Flang to support allocatable array support .

  Summary

Currently llvm rejects DWARF operator DW_OP_push_object_address.
below error is produced when llvm finds this operator.
. . . . . .

  invalid expression
  !DIExpression(151)
  warning: ignoring invalid debug info in pushobj.ll

. . . . . .
There are some parts missing in support of this operator, need to
be completed.

  Testing

-added a unit testcase
-check-debuginfo
-check-llvm


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79306

Files:
  llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
  llvm/lib/IR/DebugInfoMetadata.cpp
  llvm/test/DebugInfo/dwarfdump-pushobjectaddress.ll


Index: llvm/test/DebugInfo/dwarfdump-pushobjectaddress.ll
===================================================================
--- /dev/null
+++ llvm/test/DebugInfo/dwarfdump-pushobjectaddress.ll
@@ -0,0 +1,60 @@
+; This test checks whether DWARF operator DW_OP_push_object_address
+; is accepted and processed.
+
+; RUN: %llc_dwarf %s -O2 -filetype=obj -o %t.o
+; RUN: llvm-dwarfdump  %t.o | FileCheck %s
+
+; Test whether DW_OP_push_object_address is accepted.
+
+; CHECK-LABEL:       DW_TAG_variable
+; CHECK:        DW_AT_location
+; CHECK-SAME:        DW_OP_push_object_address
+
+; Below is the original test case this IR is generated from
+;---------------------------
+;int main() {
+;int var;
+;return var;
+;}
+;---------------------------
+; step 1: generate IR using -g -O0 -S -emit-llvm
+; step 2: insert DW_OP_push_object_address in dbg.declare instruction
+; This is meaningless test case focused to test DW_OP_push_object_address.
+
+; ModuleID = 'dwarfdump-pushobjectaddress.c'
+source_filename = "dwarfdump-pushobjectaddress.c"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+; Function Attrs: noinline nounwind optnone uwtable
+define dso_local i32 @main() !dbg !7 {
+entry:
+  %retval = alloca i32, align 4
+  %var = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  call void @llvm.dbg.declare(metadata i32* %var, metadata !11, metadata !DIExpression(DW_OP_push_object_address)), !dbg !12
+  %0 = load i32, i32* %var, align 4, !dbg !13
+  ret i32 %0, !dbg !14
+}
+
+; Function Attrs: nounwind readnone speculatable willreturn
+declare void @llvm.dbg.declare(metadata, metadata, metadata)
+
+!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 11.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "dwarfdump-pushobjectaddress.c", directory: "/dir")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{!"clang version 11.0.0"}
+!7 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !8, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{!10}
+!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!11 = !DILocalVariable(name: "var", scope: !7, file: !1, line: 2, type: !10)
+!12 = !DILocation(line: 2, column: 5, scope: !7)
+!13 = !DILocation(line: 3, column: 8, scope: !7)
+!14 = !DILocation(line: 3, column: 1, scope: !7)
Index: llvm/lib/IR/DebugInfoMetadata.cpp
===================================================================
--- llvm/lib/IR/DebugInfoMetadata.cpp
+++ llvm/lib/IR/DebugInfoMetadata.cpp
@@ -945,6 +945,7 @@
     case dwarf::DW_OP_dup:
     case dwarf::DW_OP_regx:
     case dwarf::DW_OP_bregx:
+    case dwarf::DW_OP_push_object_address:
       break;
     }
   }
Index: llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
===================================================================
--- llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -451,6 +451,7 @@
     case dwarf::DW_OP_lit0:
     case dwarf::DW_OP_not:
     case dwarf::DW_OP_dup:
+    case dwarf::DW_OP_push_object_address:
       emitOp(OpNum);
       break;
     case dwarf::DW_OP_deref:


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