[llvm-readelf/readobj] - Refine the error reporting in printMipsABIFlags() methods.

[grimar]

Summary

It fixes/improves the following:

1. Some code was duplicated.
2. A "The .MIPS.abiflags section has a wrong size" error was not reported as a warning, but was printed to stdout for the LLVM style. Also, it was reported as an error for the GNU style. This patch changes the behavior to be consistent and to report warnings.
3. unwrapOrError() was used before, now a warning is reported instead.

[atanasyan]

LGTM. Thanks

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/mips-abiflags.test

322

The implicit-check-not on the llvm-readobj case implies there is other output expected? What is this other output, and should we actually be checking it?

[grimar]

llvm/test/tools/llvm-readobj/ELF/mips-abiflags.test

322

The full output is:

File: <file name here>
Format: elf64-mips
Arch: mips64el
AddressSize: 64bit
LoadName: <Not found>
There is no .MIPS.abiflags section in the file.
There is no .MIPS.options section in the file.
There is no .reginfo section in the file.

should we actually be checking it?

It doesn't look like that to me.

[jhenderson]

llvm/test/tools/llvm-readobj/ELF/mips-abiflags.test

322

Okay, thanks.

llvm/test/tools/llvm-readobj/ELF/mips-abiflags.test

 # FLAG2-EMPTY-LLVM: Flags 2: 0x0
 
 # RUN: yaml2obj %s -DFLAG2=0xffffffff -o %t.flag2.all
 # RUN: llvm-readelf -A %t.flag2.all | FileCheck %s --check-prefix=FLAG2-ALL-GNU
 # RUN: llvm-readobj -A %t.flag2.all | FileCheck %s --check-prefix=FLAG2-ALL-LLVM
 
 # FLAG2-ALL-GNU:  FLAGS 2: ffffffff
 # FLAG2-ALL-LLVM: Flags 2: 0xFFFFFFF
+
+## Check what we print when there is no .MIPS.abiflags section in the file.
+# RUN: yaml2obj --docnum=2 %s -o %t.nosection
+## Note: GNU readelf 2.31.1 prints nothing.
+# RUN: llvm-readelf -A %t.nosection 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=NOSEC --implicit-check-not={{.}}
+# RUN: llvm-readobj -A %t.nosection 2>&1 | \
+# RUN:   FileCheck %s --check-prefixes=NOSEC,NOSEC-LLVM --implicit-check-not=warning:
+
+# NOSEC-LLVM: There is no .MIPS.abiflags section in the file.
+# NOSEC:      There is no .MIPS.options section in the file.
+# NOSEC-NEXT: There is no .reginfo section in the file.
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_MIPS
+Sections: []
+
+## Check we report a warning when we are unable to read the content of the .MIPS.abiflags section.
+# RUN: yaml2obj --docnum=3 -DSHOFFSET=0xffffffff %s -o %t.err1
+# RUN: llvm-readelf -A %t.err1 2>&1 | FileCheck %s -DFILE=%t.err1 --check-prefix=CONTENT-ERR
+# RUN: llvm-readobj -A %t.err1 2>&1 | FileCheck %s -DFILE=%t.err1 --check-prefix=CONTENT-ERR
+
+# CONTENT-ERR:      warning: '[[FILE]]': unable to read the .MIPS.abiflags section: section [index 1] has a sh_offset (0xffffffff) + sh_size (0x18) that is greater than the file size (0x240)
+# CONTENT-ERR-NEXT: There is no .MIPS.options section in the file.
+# CONTENT-ERR-NEXT: There is no .reginfo section in the file.
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_REL
+  Machine: EM_MIPS
+Sections:
+  - Name:     .MIPS.abiflags
+    Type:     SHT_MIPS_ABIFLAGS
+    ISA:      MIPS32
+    Offset:   0x100
+    ShOffset: [[SHOFFSET=0x100]]
+    ShSize:   [[SHSIZE=24]]
+
+## Check we report a warning when the .MIPS.abiflags section has an unexpected size.
+# RUN: yaml2obj --docnum=3 -DSHSIZE=23 %s -o %t.err2
+# RUN: llvm-readelf -A %t.err2 2>&1 | FileCheck %s -DFILE=%t.err2 --check-prefix=SIZE-ERR
+# RUN: llvm-readobj -A %t.err2 2>&1 | FileCheck %s -DFILE=%t.err2 --check-prefix=SIZE-ERR
+
+# SIZE-ERR:      warning: '[[FILE]]': unable to read the .MIPS.abiflags section: it has a wrong size (23)
+# SIZE-ERR-NEXT: There is no .MIPS.options section in the file.
+# SIZE-ERR-NEXT: There is no .reginfo section in the file.

llvm/tools/llvm-readobj/ELFDumper.cpp

for (auto &E : Parser.getPltEntries()) {
                                 this->dumper()->dynamic_symbols().begin());
       OS.PadToColumn(41 + 3 * Bias);
       OS << SymName << "\n";
     }
   }
 }
 
 template <class ELFT>
-void GNUStyle<ELFT>::printMipsABIFlags(const ELFObjectFile<ELFT> *ObjF) {
+Expected<const Elf_Mips_ABIFlags<ELFT> *>
+getMipsAbiFlagsSection(const ELFObjectFile<ELFT> *ObjF) {
   const ELFFile<ELFT> *Obj = ObjF->getELFFile();
-  const Elf_Shdr *Shdr =
+  const typename ELFT::Shdr *Shdr =
       findSectionByName(*Obj, ObjF->getFileName(), ".MIPS.abiflags");
   if (!Shdr)
-    return;
+    return nullptr;
 
-  ArrayRef<uint8_t> Sec =
-      unwrapOrError(ObjF->getFileName(), Obj->getSectionContents(Shdr));
-  if (Sec.size() != sizeof(Elf_Mips_ABIFlags<ELFT>))
-    reportError(createError(".MIPS.abiflags section has a wrong size"),
-                ObjF->getFileName());
+  constexpr StringRef ErrPrefix = "unable to read the .MIPS.abiflags section: ";
+  Expected<ArrayRef<uint8_t>> DataOrErr = Obj->getSectionContents(Shdr);
+  if (!DataOrErr)
+    return createError(ErrPrefix + toString(DataOrErr.takeError()));
+
+  if (DataOrErr->size() != sizeof(Elf_Mips_ABIFlags<ELFT>))
+    return createError(ErrPrefix + "it has a wrong size (" +
+        Twine(DataOrErr->size()) + ")");
+  return reinterpret_cast<const Elf_Mips_ABIFlags<ELFT> *>(DataOrErr->data());
+}
 
-  auto *Flags = reinterpret_cast<const Elf_Mips_ABIFlags<ELFT> *>(Sec.data());
+template <class ELFT>
+void GNUStyle<ELFT>::printMipsABIFlags(const ELFObjectFile<ELFT> *ObjF) {
+  const Elf_Mips_ABIFlags<ELFT> *Flags = nullptr;
+  if (Expected<const Elf_Mips_ABIFlags<ELFT> *> SecOrErr =
+          getMipsAbiFlagsSection(ObjF))
+    Flags = *SecOrErr;
+  else
+    this->reportUniqueWarning(SecOrErr.takeError());
+  if (!Flags)
+    return;
 
   OS << "MIPS ABI Flags Version: " << Flags->version << "\n\n";
   OS << "ISA: MIPS" << int(Flags->isa_level);
   if (Flags->isa_rev > 1)
     OS << "r" << int(Flags->isa_rev);
   OS << "\n";
   OS << "GPR size: " << getMipsRegisterSize(Flags->gpr_size) << "\n";
   OS << "CPR1 size: " << getMipsRegisterSize(Flags->cpr1_size) << "\n";
for (auto &E : Parser.getPltEntries()) {
           this->dumper()->getFullSymbolName(Sym, Parser.getPltStrTable(), true);
       W.printNumber("Name", SymName, Sym->st_name);
     }
   }
 }
 
 template <class ELFT>
 void LLVMStyle<ELFT>::printMipsABIFlags(const ELFObjectFile<ELFT> *ObjF) {
-  const ELFFile<ELFT> *Obj = ObjF->getELFFile();
-  const Elf_Shdr *Shdr =
-      findSectionByName(*Obj, ObjF->getFileName(), ".MIPS.abiflags");
-  if (!Shdr) {
+  const Elf_Mips_ABIFlags<ELFT> *Flags;
+  if (Expected<const Elf_Mips_ABIFlags<ELFT> *> SecOrErr =
+          getMipsAbiFlagsSection(ObjF)) {
+    Flags = *SecOrErr;
+    if (!Flags) {
       W.startLine() << "There is no .MIPS.abiflags section in the file.\n";
       return;
     }
-  ArrayRef<uint8_t> Sec =
-      unwrapOrError(ObjF->getFileName(), Obj->getSectionContents(Shdr));
-  if (Sec.size() != sizeof(Elf_Mips_ABIFlags<ELFT>)) {
-    W.startLine() << "The .MIPS.abiflags section has a wrong size.\n";
+  } else {
+    this->reportUniqueWarning(SecOrErr.takeError());
     return;
   }
 
-  auto *Flags = reinterpret_cast<const Elf_Mips_ABIFlags<ELFT> *>(Sec.data());
-
   raw_ostream &OS = W.getOStream();
   DictScope GS(W, "MIPS ABI Flags");
 
   W.printNumber("Version", Flags->version);
   W.startLine() << "ISA: ";
   if (Flags->isa_rev <= 1)
     OS << format("MIPS%u", Flags->isa_level);
   else