[llvm-readobj] - Teach tool to report error if some section is in multiple COMDAT groups at once.

readelf tool reports an error when output contains the same section
in multiple COMDAT groups. That can be useful.
Path teaches llvm-readobj to do the same.

Differential revision: https://reviews.llvm.org/D37567

llvm-svn: 313459

1 files changed, 38 insertions, 2 deletions

diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 4867b473fec..a826e041ecd 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -18,6 +18,7 @@
 #include "StackMapPrinter.h"
 #include "llvm-readobj.h"
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallString.h"
@@ -2489,18 +2490,40 @@ std::vector<GroupSection> getGroups(const ELFFile<ELFT> *Obj) {
   }
   return Ret;
 }
+
+DenseMap<uint64_t, const GroupSection *>
+mapSectionsToGroups(ArrayRef<GroupSection> Groups) {
+  DenseMap<uint64_t, const GroupSection *> Ret;
+  for (const GroupSection &G : Groups)
+    for (const GroupMember &GM : G.Members)
+      Ret.insert({GM.Index, &G});
+  return Ret;
+}
+
 } // namespace
 
 template <class ELFT> void GNUStyle<ELFT>::printGroupSections(const ELFO *Obj) {
   std::vector<GroupSection> V = getGroups<ELFT>(Obj);
+  DenseMap<uint64_t, const GroupSection *> Map = mapSectionsToGroups(V);
   for (const GroupSection &G : V) {
     OS << "\n"
        << getGroupType(G.Type) << " group section ["
        << format_decimal(G.Index, 5) << "] `" << G.Name << "' [" << G.Signature
        << "] contains " << G.Members.size() << " sections:\n"
        << "   [Index]    Name\n";
-    for (const GroupMember &GM : G.Members)
+    for (const GroupMember &GM : G.Members) {
+      const GroupSection *MainGroup = Map[GM.Index];
+      if (MainGroup != &G) {
+        OS.flush();
+        errs() << "Error: section [" << format_decimal(GM.Index, 5)
+               << "] in group section [" << format_decimal(G.Index, 5)
+               << "] already in group section ["
+               << format_decimal(MainGroup->Index, 5) << "]";
+        errs().flush();
+        continue;
+      }
       OS << "   [" << format_decimal(GM.Index, 5) << "]   " << GM.Name << "\n";
+    }
   }
 
   if (V.empty())
@@ -3525,6 +3548,7 @@ template <class ELFT>
 void LLVMStyle<ELFT>::printGroupSections(const ELFO *Obj) {
   DictScope Lists(W, "Groups");
   std::vector<GroupSection> V = getGroups<ELFT>(Obj);
+  DenseMap<uint64_t, const GroupSection *> Map = mapSectionsToGroups(V);
   for (const GroupSection &G : V) {
     DictScope D(W, "Group");
     W.printNumber("Name", G.Name, G.ShName);
@@ -3533,13 +3557,25 @@ void LLVMStyle<ELFT>::printGroupSections(const ELFO *Obj) {
     W.startLine() << "Signature: " << G.Signature << "\n";
 
     ListScope L(W, "Section(s) in group");
-    for (const GroupMember &GM : G.Members)
+    for (const GroupMember &GM : G.Members) {
+      const GroupSection *MainGroup = Map[GM.Index];
+      if (MainGroup != &G) {
+        W.flush();
+        errs() << "Error: " << GM.Name << " (" << GM.Index
+               << ") in a group " + G.Name + " (" << G.Index
+               << ") is already in a group " + MainGroup->Name + " ("
+               << MainGroup->Index << ")\n";
+        errs().flush();
+        continue;
+      }
       W.startLine() << GM.Name << " (" << GM.Index << ")\n";
+    }
   }
 
   if (V.empty())
     W.startLine() << "There are no group sections in the file.\n";
 }
+
 template <class ELFT> void LLVMStyle<ELFT>::printRelocations(const ELFO *Obj) {
   ListScope D(W, "Relocations");