[llvm-objcopy][ELF] Add --set-section-type

The request is mentioned on D129053. I feel that having this functionality is
mildly useful (not strong).

* Rename .ctors to .init_array and change sh_type to SHT_INIT_ARRAY (GNU objcopy
  detects the special name but we don't).
* Craft tests for a new SHT_LLVM_* extension

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D129337

2 files changed, 34 insertions, 19 deletions

diff --git a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
index 30ca506..8a2b485 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
+++ b/llvm/tools/llvm-objcopy/ObjcopyOptions.cpp
@@ -236,23 +236,21 @@ static Expected<SectionRename> parseRenameSectionValue(StringRef FlagValue) {
 }
 
 static Expected<std::pair<StringRef, uint64_t>>
-parseSetSectionAlignment(StringRef FlagValue) {
+parseSetSectionAttribute(StringRef Option, StringRef FlagValue) {
   if (!FlagValue.contains('='))
-    return createStringError(
-        errc::invalid_argument,
-        "bad format for --set-section-alignment: missing '='");
+    return make_error<StringError>("bad format for " + Option + ": missing '='",
+                                   errc::invalid_argument);
   auto Split = StringRef(FlagValue).split('=');
   if (Split.first.empty())
-    return createStringError(
-        errc::invalid_argument,
-        "bad format for --set-section-alignment: missing section name");
-  uint64_t NewAlign;
-  if (Split.second.getAsInteger(0, NewAlign))
-    return createStringError(
-        errc::invalid_argument,
-        "invalid alignment for --set-section-alignment: '%s'",
-        Split.second.str().c_str());
-  return std::make_pair(Split.first, NewAlign);
+    return make_error<StringError>("bad format for " + Option +
+                                       ": missing section name",
+                                   errc::invalid_argument);
+  uint64_t Value;
+  if (Split.second.getAsInteger(0, Value))
+    return make_error<StringError>("invalid value for " + Option + ": '" +
+                                       Split.second + "'",
+                                   errc::invalid_argument);
+  return std::make_pair(Split.first, Value);
 }
 
 static Expected<SectionFlagsUpdate>
@@ -793,7 +791,7 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
   }
   for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_alignment)) {
     Expected<std::pair<StringRef, uint64_t>> NameAndAlign =
-        parseSetSectionAlignment(Arg->getValue());
+        parseSetSectionAttribute("--set-section-alignment", Arg->getValue());
     if (!NameAndAlign)
       return NameAndAlign.takeError();
     Config.SetSectionAlignment[NameAndAlign->first] = NameAndAlign->second;
@@ -809,16 +807,28 @@ objcopy::parseObjcopyOptions(ArrayRef<const char *> RawArgsArr,
           "--set-section-flags set multiple times for section '%s'",
           SFU->Name.str().c_str());
   }
-  // Prohibit combinations of --set-section-flags when the section name is used
-  // as the destination of a --rename-section.
+  for (auto Arg : InputArgs.filtered(OBJCOPY_set_section_type)) {
+    Expected<std::pair<StringRef, uint64_t>> NameAndType =
+        parseSetSectionAttribute("--set-section-type", Arg->getValue());
+    if (!NameAndType)
+      return NameAndType.takeError();
+    Config.SetSectionType[NameAndType->first] = NameAndType->second;
+  }
+  // Prohibit combinations of --set-section-{flags,type} when the section name
+  // is used as the destination of a --rename-section.
   for (const auto &E : Config.SectionsToRename) {
     const SectionRename &SR = E.second;
-    if (Config.SetSectionFlags.count(SR.NewName))
+    auto Err = [&](const char *Option) {
       return createStringError(
           errc::invalid_argument,
-          "--set-section-flags=%s conflicts with --rename-section=%s=%s",
+          "--set-section-%s=%s conflicts with --rename-section=%s=%s", Option,
           SR.NewName.str().c_str(), SR.OriginalName.str().c_str(),
           SR.NewName.str().c_str());
+    };
+    if (Config.SetSectionFlags.count(SR.NewName))
+      return Err("flags");
+    if (Config.SetSectionType.count(SR.NewName))
+      return Err("type");
   }
 
   for (auto Arg : InputArgs.filtered(OBJCOPY_remove_section))
diff --git a/llvm/tools/llvm-objcopy/ObjcopyOpts.td b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
index ff732659..962028d 100644
--- a/llvm/tools/llvm-objcopy/ObjcopyOpts.td
+++ b/llvm/tools/llvm-objcopy/ObjcopyOpts.td
@@ -87,6 +87,11 @@ defm set_section_flags
          "data, rom, share, contents, merge, strings.">,
       MetaVarName<"section=flag1[,flag2,...]">;
 
+defm set_section_type
+    : Eq<"set-section-type",
+         "Set the type of section <section> to the integer <type>">,
+      MetaVarName<"section=type">;
+
 def S : Flag<["-"], "S">,
         Alias<strip_all>,
         HelpText<"Alias for --strip-all">;