Recommit r368812 "[llvm/Object] - Convert SectionRef::getName() to return Expected<>"

Changes: no changes. A fix for the clang code will be landed right on top.

Original commit message:

SectionRef::getName() returns std::error_code now.
Returning Expected<> instead has multiple benefits.

For example, it forces user to check the error returned.
Also Expected<> may keep a valuable string error message,
what is more useful than having a error code.
(Object\invalid.test was updated to show the new messages printed.)

This patch makes a change for all users to switch to Expected<> version.

Note: in a few places the error returned was ignored before my changes.
In such places I left them ignored. My intention was to convert the interface
used, and not to improve and/or the existent users in this patch.
(Though I think this is good idea for a follow-ups to revisit such places
and either remove consumeError calls or comment each of them to clarify why
it is OK to have them).

Differential revision: https://reviews.llvm.org/D66089

llvm-svn: 368826

5 files changed, 33 insertions, 20 deletions

diff --git a/llvm/lib/Object/COFFObjectFile.cpp b/llvm/lib/Object/COFFObjectFile.cpp
index 854664e679d..afd68694deb 100644
--- a/llvm/lib/Object/COFFObjectFile.cpp
+++ b/llvm/lib/Object/COFFObjectFile.cpp
@@ -994,11 +994,12 @@ std::error_code COFFObjectFile::getSection(int32_t Index,
 std::error_code COFFObjectFile::getSection(StringRef SectionName,
                                            const coff_section *&Result) const {
   Result = nullptr;
-  StringRef SecName;
   for (const SectionRef &Section : sections()) {
-    if (std::error_code E = Section.getName(SecName))
-      return E;
-    if (SecName == SectionName) {
+    auto NameOrErr = Section.getName();
+    if (!NameOrErr)
+      return errorToErrorCode(NameOrErr.takeError());
+
+    if (*NameOrErr == SectionName) {
       Result = getCOFFSection(Section);
       return std::error_code();
     }
diff --git a/llvm/lib/Object/Decompressor.cpp b/llvm/lib/Object/Decompressor.cpp
index 53b8e846e5f..11efd857d1a 100644
--- a/llvm/lib/Object/Decompressor.cpp
+++ b/llvm/lib/Object/Decompressor.cpp
@@ -77,10 +77,15 @@ bool Decompressor::isGnuStyle(StringRef Name) {
 }
 
 bool Decompressor::isCompressed(const object::SectionRef &Section) {
-  StringRef Name;
-  if (Section.getName(Name))
-    return false;
-  return Section.isCompressed() || isGnuStyle(Name);
+  if (Section.isCompressed())
+    return true;
+
+  Expected<StringRef> SecNameOrErr = Section.getName();
+  if (SecNameOrErr)
+    return isGnuStyle(*SecNameOrErr);
+
+  consumeError(SecNameOrErr.takeError());
+  return false;
 }
 
 bool Decompressor::isCompressedELFSection(uint64_t Flags, StringRef Name) {
diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index 9945018d957..f3b0347088a 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -392,9 +392,13 @@ ELFObjectFileBase::getPltAddresses() const {
     return {};
   Optional<SectionRef> Plt = None, RelaPlt = None, GotPlt = None;
   for (const SectionRef &Section : sections()) {
-    StringRef Name;
-    if (Section.getName(Name))
+    Expected<StringRef> NameOrErr = Section.getName();
+    if (!NameOrErr) {
+      consumeError(NameOrErr.takeError());
       continue;
+    }
+    StringRef Name = *NameOrErr;
+
     if (Name == ".plt")
       Plt = Section;
     else if (Name == ".rela.plt" || Name == ".rel.plt")
diff --git a/llvm/lib/Object/MachOObjectFile.cpp b/llvm/lib/Object/MachOObjectFile.cpp
index 3bfbfe06944..179166ddbd3 100644
--- a/llvm/lib/Object/MachOObjectFile.cpp
+++ b/llvm/lib/Object/MachOObjectFile.cpp
@@ -1986,13 +1986,12 @@ Expected<SectionRef> MachOObjectFile::getSection(unsigned SectionIndex) const {
 }
 
 Expected<SectionRef> MachOObjectFile::getSection(StringRef SectionName) const {
-  StringRef SecName;
   for (const SectionRef &Section : sections()) {
-    if (std::error_code E = Section.getName(SecName))
-      return errorCodeToError(E);
-    if (SecName == SectionName) {
+    auto NameOrErr = Section.getName();
+    if (!NameOrErr)
+      return NameOrErr.takeError();
+    if (*NameOrErr == SectionName)
       return Section;
-    }
   }
   return errorCodeToError(object_error::parse_failed);
 }
@@ -3995,7 +3994,11 @@ BindRebaseSegInfo::BindRebaseSegInfo(const object::MachOObjectFile *Obj) {
   uint64_t CurSegAddress;
   for (const SectionRef &Section : Obj->sections()) {
     SectionInfo Info;
-    Section.getName(Info.SectionName);
+    Expected<StringRef> NameOrErr = Section.getName();
+    if (!NameOrErr)
+      consumeError(NameOrErr.takeError());
+    else
+      Info.SectionName = *NameOrErr;
     Info.Address = Section.getAddress();
     Info.Size = Section.getSize();
     Info.SegmentName =
diff --git a/llvm/lib/Object/Object.cpp b/llvm/lib/Object/Object.cpp
index d84798cc6dd..b518e2d02c9 100644
--- a/llvm/lib/Object/Object.cpp
+++ b/llvm/lib/Object/Object.cpp
@@ -251,10 +251,10 @@ void LLVMMoveToNextSymbol(LLVMSymbolIteratorRef SI) {
 
 // SectionRef accessors
 const char *LLVMGetSectionName(LLVMSectionIteratorRef SI) {
-  StringRef ret;
-  if (std::error_code ec = (*unwrap(SI))->getName(ret))
-   report_fatal_error(ec.message());
-  return ret.data();
+  auto NameOrErr = (*unwrap(SI))->getName();
+  if (!NameOrErr)
+    report_fatal_error(NameOrErr.takeError());
+  return NameOrErr->data();
 }
 
 uint64_t LLVMGetSectionSize(LLVMSectionIteratorRef SI) {