[PATCH] D40199: llvm-dwarfdump --verify is incorrectly saying all DW_AT_location attributes with locations lists are invalid.

[Jonas Devlieghere via Phabricator via llvm-commits]

JDevlieghere updated this revision to Diff 133616.
JDevlieghere added a comment.
Herald added a subscriber: hiraditya.

- Address review comments
- Add test case


https://reviews.llvm.org/D40199

Files:
  llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
  llvm/test/tools/llvm-dwarfdump/X86/debugloc.s


Index: llvm/test/tools/llvm-dwarfdump/X86/debugloc.s
===================================================================
--- llvm/test/tools/llvm-dwarfdump/X86/debugloc.s
+++ llvm/test/tools/llvm-dwarfdump/X86/debugloc.s
@@ -2,6 +2,10 @@
 # RUN: | llvm-dwarfdump --debug-loc - \
 # RUN: | FileCheck %s
 
+# RUN: llvm-mc %s -filetype obj -triple x86_64-linux-elf -o - \
+# RUN: | llvm-dwarfdump --verify - \
+# RUN: | FileCheck %s --check-prefix VERIFY
+
 # CHECK: .debug_loc contents:
 
 # CHECK: 0x00000000:
@@ -12,6 +16,9 @@
 # CHECK-NEXT: [0x0000000000000010, 0x0000000000000013): DW_OP_reg5 RDI
 # CHECK-NEXT: [0x0000000000000013, 0x0000000000000014): DW_OP_reg0 RAX
 
+# VERIFY: Verifying .debug_info Unit Header Chain
+# VERIFY-NOT: DIE has invalid DW_AT_location encoding
+
 # Source:
 #   int* foo(int* i) { return i; }
 #   int* bar(int* i) { return i; }
Index: llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -410,22 +410,30 @@
     ReportError("DIE has invalid DW_AT_stmt_list encoding:");
     break;
   case DW_AT_location: {
-    Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock();
-    if (!Expr) {
-      ReportError("DIE has invalid DW_AT_location encoding:");
-      break;
+    auto VerifyLocation = [&](const void *data, size_t len) {
+      DWARFUnit *U = Die.getDwarfUnit();
+      DataExtractor Data(StringRef(reinterpret_cast<const char *>(data), len),
+                         DCtx.isLittleEndian(), 0);
+      DWARFExpression Expression(Data, U->getVersion(),
+                                 U->getAddressByteSize());
+      bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
+        return Op.isError();
+      });
+      if (Error)
+        ReportError("DIE contains invalid DWARF expression:");
+    };
+    if (Optional<ArrayRef<uint8_t>> Expr = AttrValue.Value.getAsBlock()) {
+      // Inlined location
+      VerifyLocation(Expr->data(), Expr->size());
+    } else if (auto LocOffset = AttrValue.Value.getAsUnsignedConstant()) {
+      // Location list
+      if (auto DebugLoc = DCtx.getDebugLoc()) {
+        if (auto LocList = DebugLoc->getLocationListAtOffset(*LocOffset)) {
+          for (const auto &Entry : LocList->Entries)
+            VerifyLocation(Entry.Loc.data(), Entry.Loc.size());
+        }
+      }
     }
-
-    DWARFUnit *U = Die.getDwarfUnit();
-    DataExtractor Data(
-        StringRef(reinterpret_cast<const char *>(Expr->data()), Expr->size()),
-        DCtx.isLittleEndian(), 0);
-    DWARFExpression Expression(Data, U->getVersion(), U->getAddressByteSize());
-    bool Error = llvm::any_of(Expression, [](DWARFExpression::Operation &Op) {
-      return Op.isError();
-    });
-    if (Error)
-      ReportError("DIE contains invalid DWARF expression:");
     break;
   }
 


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