[PATCH] D13814: Add support for SHF_MERGE sections

[Shankar Easwaran via llvm-commits]

shankare added a subscriber: shankare.

================
Comment at: ELF/InputFiles.cpp:160
@@ -157,1 +159,3 @@
+      else
+        error("bar");
       break;
----------------
An appropriate error message might be needed here.

================
Comment at: ELF/InputFiles.cpp:164
@@ -159,2 +163,3 @@
     default:
-      Sections[I] = new (this->Alloc) InputSection<ELFT>(this, &Sec);
+      if (Sec.sh_flags & SHF_MERGE)
+        Sections[I] = new (this->Alloc) MergeInputSection<ELFT>(this, &Sec);
----------------
Linker can merge across readonly merge sections. You might want to check that section flags do not have write permission.

================
Comment at: ELF/InputSection.cpp:74-75
@@ +73,4 @@
+    return Addend;
+  if (Sym->getType() != STT_SECTION)
+    return Addend;
+
----------------
You can also have a relocation to a local symbol in a merge section. For the local symbol usecase in a merge string section you would need to get the value of the local symbol too.

================
Comment at: ELF/InputSection.cpp:168
@@ +167,3 @@
+  if (Value + EntSize > Data.size())
+    error("zed");
+  Data = Data.slice(Value, EntSize);
----------------
Error message.

================
Comment at: ELF/OutputSections.cpp:479
@@ +478,3 @@
+  if (Offset + EntSize > Data.size())
+    error("zed");
+
----------------
error message.

================
Comment at: ELF/OutputSections.cpp:564
@@ +563,3 @@
+unsigned MergeOutputSection<ELFT>::getOffset(ArrayRef<uint8_t> Val) {
+  StringRef Hack((char *)Val.data(), Val.size());
+  auto I = Offsets.find(Hack);
----------------
Can we change the variable names and error messages to be proper ?

================
Comment at: ELF/OutputSections.cpp:567
@@ +566,3 @@
+  if (I == Offsets.end())
+    error("foo");
+  return I->second;
----------------
error message.


http://reviews.llvm.org/D13814