[llvm-objcopy] Add --prefix-alloc-sections
This patch adds support for --prefix-alloc-sections, which adds a prefix
to every allocated section names.
It adds a prefix after renaming section names by --rename-section as GNU
objcopy does.
Fixes PR41266: https://bugs.llvm.org/show_bug.cgi?id=41266
Differential Revision: https://reviews.llvm.org/D60042
Patch by Seiya Nuta.
llvm-svn: 360233
diff --git a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
index 9b21190..bed2414 100644
--- a/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
+++ b/llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
@@ -13,6 +13,7 @@
#include "llvm-objcopy.h"
#include "llvm/ADT/BitmaskEnum.h"
+#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
@@ -580,7 +581,8 @@
if (Error E = updateAndRemoveSymbols(Config, Obj))
return E;
- if (!Config.SectionsToRename.empty()) {
+ if (!Config.SectionsToRename.empty() || !Config.AllocSectionsPrefix.empty()) {
+ DenseSet<SectionBase *> PrefixedSections;
for (auto &Sec : Obj.sections()) {
const auto Iter = Config.SectionsToRename.find(Sec.Name);
if (Iter != Config.SectionsToRename.end()) {
@@ -589,6 +591,60 @@
if (SR.NewFlags.hasValue())
setSectionFlagsAndType(Sec, SR.NewFlags.getValue());
}
+
+ // Add a prefix to allocated sections and their relocation sections. This
+ // should be done after renaming the section by Config.SectionToRename to
+ // imitate the GNU objcopy behavior.
+ if (!Config.AllocSectionsPrefix.empty()) {
+ if (Sec.Flags & SHF_ALLOC) {
+ Sec.Name = (Config.AllocSectionsPrefix + Sec.Name).str();
+ PrefixedSections.insert(&Sec);
+
+ // Rename relocation sections associated to the allocated sections.
+ // For example, if we rename .text to .prefix.text, we also rename
+ // .rel.text to .rel.prefix.text.
+ //
+ // Dynamic relocation sections (SHT_REL[A] with SHF_ALLOC) are handled
+ // above, e.g., .rela.plt is renamed to .prefix.rela.plt, not
+ // .rela.prefix.plt since GNU objcopy does so.
+ } else if (auto *RelocSec = dyn_cast<RelocationSectionBase>(&Sec)) {
+ auto *TargetSec = RelocSec->getSection();
+ if (TargetSec && (TargetSec->Flags & SHF_ALLOC)) {
+ StringRef prefix;
+ switch (Sec.Type) {
+ case SHT_REL:
+ prefix = ".rel";
+ break;
+ case SHT_RELA:
+ prefix = ".rela";
+ break;
+ default:
+ continue;
+ }
+
+ // If the relocation section comes *after* the target section, we
+ // don't add Config.AllocSectionsPrefix because we've already added
+ // the prefix to TargetSec->Name. Otherwise, if the relocation
+ // section comes *before* the target section, we add the prefix.
+ if (PrefixedSections.count(TargetSec)) {
+ Sec.Name = (prefix + TargetSec->Name).str();
+ } else {
+ const auto Iter = Config.SectionsToRename.find(TargetSec->Name);
+ if (Iter != Config.SectionsToRename.end()) {
+ // Both `--rename-section` and `--prefix-alloc-sections` are
+ // given but the target section is not yet renamed.
+ Sec.Name =
+ (prefix + Config.AllocSectionsPrefix + Iter->second.NewName)
+ .str();
+ } else {
+ Sec.Name =
+ (prefix + Config.AllocSectionsPrefix + TargetSec->Name)
+ .str();
+ }
+ }
+ }
+ }
+ }
}
}