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

1 files changed, 36 insertions, 21 deletions

diff --git a/llvm/tools/llvm-objdump/llvm-objdump.cpp b/llvm/tools/llvm-objdump/llvm-objdump.cpp
index 9383385..7a04e11 100644
--- a/llvm/tools/llvm-objdump/llvm-objdump.cpp
+++ b/llvm/tools/llvm-objdump/llvm-objdump.cpp
@@ -344,10 +344,14 @@ typedef std::vector<std::tuple<uint64_t, StringRef, uint8_t>> SectionSymbolsTy;
 static bool shouldKeep(object::SectionRef S) {
   if (FilterSections.empty())
     return true;
-  StringRef SecName;
-  std::error_code error = S.getName(SecName);
-  if (error)
+
+  Expected<StringRef> SecNameOrErr = S.getName();
+  if (!SecNameOrErr) {
+    consumeError(SecNameOrErr.takeError());
     return false;
+  }
+  StringRef SecName = *SecNameOrErr;
+
   // StringSet does not allow empty key so avoid adding sections with
   // no name (such as the section with index 0) here.
   if (!SecName.empty())
@@ -920,10 +924,12 @@ static void addPltEntries(const ObjectFile *Obj,
                           StringSaver &Saver) {
   Optional<SectionRef> Plt = None;
   for (const SectionRef &Section : Obj->sections()) {
-    StringRef Name;
-    if (Section.getName(Name))
+    Expected<StringRef> SecNameOrErr = Section.getName();
+    if (!SecNameOrErr) {
+      consumeError(SecNameOrErr.takeError());
       continue;
-    if (Name == ".plt")
+    }
+    if (*SecNameOrErr == ".plt")
       Plt = Section;
   }
   if (!Plt)
@@ -1206,9 +1212,8 @@ static void disassembleObject(const Target *TheTarget, const ObjectFile *Obj,
       DataRefImpl DR = Section.getRawDataRefImpl();
       SegmentName = MachO->getSectionFinalSegmentName(DR);
     }
-    StringRef SectionName;
-    error(Section.getName(SectionName));
 
+    StringRef SectionName = unwrapOrError(Section.getName(), Obj->getFileName());
     // If the section has no symbol at the start, just insert a dummy one.
     if (Symbols.empty() || std::get<0>(Symbols[0]) != 0) {
       Symbols.insert(
@@ -1581,8 +1586,7 @@ void printRelocations(const ObjectFile *Obj) {
   }
 
   for (std::pair<SectionRef, std::vector<SectionRef>> &P : SecToRelSec) {
-    StringRef SecName;
-    error(P.first.getName(SecName));
+    StringRef SecName = unwrapOrError(P.first.getName(), Obj->getFileName());
     outs() << "RELOCATION RECORDS FOR [" << SecName << "]:\n";
 
     for (SectionRef Section : P.second) {
@@ -1654,8 +1658,7 @@ void printSectionHeaders(const ObjectFile *Obj) {
               "Idx Name          Size     VMA          Type\n";
 
   for (const SectionRef &Section : ToolSectionFilter(*Obj)) {
-    StringRef Name;
-    error(Section.getName(Name));
+    StringRef Name = unwrapOrError(Section.getName(), Obj->getFileName());
     uint64_t VMA = Section.getAddress();
     if (shouldAdjustVA(Section))
       VMA += AdjustVMA;
@@ -1682,8 +1685,7 @@ void printSectionHeaders(const ObjectFile *Obj) {
 
 void printSectionContents(const ObjectFile *Obj) {
   for (const SectionRef &Section : ToolSectionFilter(*Obj)) {
-    StringRef Name;
-    error(Section.getName(Name));
+    StringRef Name = unwrapOrError(Section.getName(), Obj->getFileName());
     uint64_t BaseAddr = Section.getAddress();
     uint64_t Size = Section.getSize();
     if (!Size)
@@ -1747,11 +1749,16 @@ void printSymbolTable(const ObjectFile *O, StringRef ArchiveName,
     section_iterator Section = unwrapOrError(Symbol.getSection(), ArchiveName,
                                              FileName, ArchitectureName);
     StringRef Name;
-    if (Type == SymbolRef::ST_Debug && Section != O->section_end())
-      Section->getName(Name);
-    else
+    if (Type == SymbolRef::ST_Debug && Section != O->section_end()) {
+      if (Expected<StringRef> NameOrErr = Section->getName())
+        Name = *NameOrErr;
+      else
+        consumeError(NameOrErr.takeError());
+
+    } else {
       Name = unwrapOrError(Symbol.getName(), ArchiveName, FileName,
                            ArchitectureName);
+    }
 
     bool Global = Flags & SymbolRef::SF_Global;
     bool Weak = Flags & SymbolRef::SF_Weak;
@@ -1797,8 +1804,8 @@ void printSymbolTable(const ObjectFile *O, StringRef ArchiveName,
         StringRef SegmentName = MachO->getSectionFinalSegmentName(DR);
         outs() << SegmentName << ",";
       }
-      StringRef SectionName;
-      error(Section->getName(SectionName));
+      StringRef SectionName =
+          unwrapOrError(Section->getName(), O->getFileName());
       outs() << SectionName;
     }
 
@@ -1871,7 +1878,11 @@ void printRawClangAST(const ObjectFile *Obj) {
   Optional<object::SectionRef> ClangASTSection;
   for (auto Sec : ToolSectionFilter(*Obj)) {
     StringRef Name;
-    Sec.getName(Name);
+    if (Expected<StringRef> NameOrErr = Sec.getName())
+      Name = *NameOrErr;
+    else
+      consumeError(NameOrErr.takeError());
+
     if (Name == ClangASTSectionName) {
       ClangASTSection = Sec;
       break;
@@ -1903,7 +1914,11 @@ static void printFaultMaps(const ObjectFile *Obj) {
 
   for (auto Sec : ToolSectionFilter(*Obj)) {
     StringRef Name;
-    Sec.getName(Name);
+    if (Expected<StringRef> NameOrErr = Sec.getName())
+      Name = *NameOrErr;
+    else
+      consumeError(NameOrErr.takeError());
+
     if (Name == FaultMapSectionName) {
       FaultMapSection = Sec;
       break;