[ELF] Refactor several fatal error messages

[evgeny777]

Summary

This patch does the following:

• Adds ":" in string returned by getName(), so that error messages conform the current style
• Puts file name before error message
• Prints location for non-ABS reloc error and adds test case for it.

[ruiu]

LGTM

ELF/InputFiles.cpp

784

This should be llvm_unreachable.

[evgeny777]

ELF/InputFiles.cpp

784

This is checked in ELF/invalid/invalid-elf.text

ELF/InputFiles.cpp

 }
 
 template <template <class> class T>
 static InputFile *createELFFile(MemoryBufferRef MB) {
   unsigned char Size;
   unsigned char Endian;
   std::tie(Size, Endian) = getElfArchType(MB.getBuffer());
   if (Endian != ELFDATA2LSB && Endian != ELFDATA2MSB)
-    fatal("invalid data encoding: " + MB.getBufferIdentifier());
+    fatal(MB.getBufferIdentifier() + ": invalid data encoding");
 
   size_t BufSize = MB.getBuffer().size();
   if ((Size == ELFCLASS32 && BufSize < sizeof(Elf32_Ehdr)) ||
       (Size == ELFCLASS64 && BufSize < sizeof(Elf64_Ehdr)))
-    fatal("file is too short");
+    fatal(MB.getBufferIdentifier() + ": file is too short");
 
   InputFile *Obj;
   if (Size == ELFCLASS32 && Endian == ELFDATA2LSB)
     Obj = make<T<ELF32LE>>(MB);
   else if (Size == ELFCLASS32 && Endian == ELFDATA2MSB)
     Obj = make<T<ELF32BE>>(MB);
   else if (Size == ELFCLASS64 && Endian == ELFDATA2LSB)
     Obj = make<T<ELF64LE>>(MB);
   else if (Size == ELFCLASS64 && Endian == ELFDATA2MSB)
     Obj = make<T<ELF64BE>>(MB);
   else
-    fatal("invalid file class: " + MB.getBufferIdentifier());
+    fatal(MB.getBufferIdentifier() + ": invalid file class");
 
   if (!Config->FirstElf)
     Config->FirstElf = Obj;
   return Obj;
 }
 
 template <class ELFT> void BinaryFile::parse() {
   StringRef Buf = MB.getBuffer();

ELF/InputSection.cpp

 #include "InputSection.h"
 #include "Config.h"
 #include "EhFrame.h"
 #include "Error.h"
 #include "InputFiles.h"
 #include "LinkerScript.h"
 #include "Memory.h"
 #include "OutputSections.h"
+#include "Relocations.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "Thunks.h"
 
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/Endian.h"
 
 using namespace llvm;
if (auto *D = dyn_cast<InputSection<ELFT>>(this))
     if (D->getThunksSize() > 0)
       return D->getThunkOff() + D->getThunksSize();
 
   return Data.size();
 }
 
 // Returns a string for an error message.
 template <class SectionT> static std::string getName(SectionT *Sec) {
-  return (Sec->getFile()->getName() + "(" + Sec->Name + ")").str();
+  return (Sec->getFile()->getName() + ":(" + Sec->Name + ")").str();
 }
 
 template <class ELFT>
 typename ELFT::uint InputSectionBase<ELFT>::getOffset(uintX_t Offset) const {
   switch (kind()) {
   case Regular:
     return cast<InputSection<ELFT>>(this)->OutSecOff + Offset;
   case Synthetic:
for (const RelTy &Rel : Rels) {
     uintX_t Offset = this->getOffset(Rel.r_offset);
     uint8_t *BufLoc = Buf + Offset;
     uintX_t Addend = getAddend<ELFT>(Rel);
     if (!RelTy::IsRela)
       Addend += Target->getImplicitAddend(BufLoc, Type);
 
     SymbolBody &Sym = this->File->getRelocTargetSym(Rel);
     if (Target->getRelExpr(Type, Sym) != R_ABS) {
-      error(getName(this) + " has non-ABS reloc");
+      error(getLocation(*this, Offset) + ": has non-ABS reloc");
       return;
     }
 
     uintX_t AddrLoc = this->OutSec->Addr + Offset;
     uint64_t SymVA = 0;
     if (!Sym.isTls() || Out<ELFT>::TlsPhdr)
       SymVA = SignExtend64<sizeof(uintX_t) * 8>(
           getSymVA<ELFT>(Type, Addend, AddrLoc, Sym, R_ABS));

ELF/LTO.cpp

 static void undefine(Symbol *S) {
   replaceBody<Undefined>(S, S->body()->getName(), STV_DEFAULT, S->body()->Type,
                          nullptr);
 }
 
 void BitcodeCompiler::add(BitcodeFile &F) {
   lto::InputFile &Obj = *F.Obj;
   if (Obj.getDataLayoutStr().empty())
-    fatal("invalid bitcode file: " + F.getName() + " has no datalayout");
+    fatal(F.getName() + ": is invlid - no datalayout");
 
   unsigned SymNum = 0;
   std::vector<Symbol *> Syms = F.getSymbols();
   std::vector<lto::SymbolResolution> Resols(Syms.size());
 
   // Provide a resolution to the LTO API for each symbol.
   for (const lto::InputFile::Symbol &ObjSym : Obj.symbols()) {
     Symbol *Sym = Syms[SymNum];

test/ELF/invalid/invalid-elf.test

 # RUN: llvm-mc %s -o %t -filetype=obj -triple x86_64-pc-linux
 
 # RUN: not ld.lld %t %p/Inputs/data-encoding.a -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=INVALID-DATA-ENC %s
-# INVALID-DATA-ENC: invalid data encoding: test.o
+# INVALID-DATA-ENC: test.o: invalid data encoding
 
 # RUN: not ld.lld %t %p/Inputs/file-class.a -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=INVALID-FILE-CLASS %s
-# INVALID-FILE-CLASS: invalid file class: test.o
+# INVALID-FILE-CLASS: test.o: invalid file class
 
 # RUN: not ld.lld %p/Inputs/symtab-sh_info.elf -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=INVALID-SYMTAB-SHINFO %s
 # INVALID-SYMTAB-SHINFO: invalid sh_info in symbol table
 
 # RUN: not ld.lld %p/Inputs/binding.elf -o %t2 2>&1 | \
 # RUN:   FileCheck --check-prefix=INVALID-BINDING %s
 # INVALID-BINDING: unexpected binding

test/ELF/lto/invalid-bitcode.ll

 ; REQUIRES: x86
 ; RUN: llvm-as %s -o %t.o
 ; RUN: not ld.lld -m elf_x86_64 %t.o 2>&1 | FileCheck %s
 
-; CHECK: invalid bitcode file:
+; CHECK: {{.*}}: is invalid - no datalayout
 
 ; This bitcode file has no datalayout.
 target triple = "x86_64-unknown-linux-gnu"
 
 define void @_start() {
   ret void
 }

test/ELF/merge-string-error.s

 // REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
 // RUN: not ld.lld %t.o -o %t.so -shared 2>&1 | FileCheck %s
 
         .section  .rodata.str1.1,"aMS",@progbits,1
   .asciz  "abc"
 
         .data
         .long .rodata.str1.1 + 4
 
-// CHECK: merge-string-error.s.tmp.o(.rodata.str1.1): entry is past the end of the section
+// CHECK: merge-string-error.s.tmp.o:(.rodata.str1.1): entry is past the end of the section

test/ELF/non-abs-reloc.s

+// REQUIRES: x86
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
+// RUN: not ld.lld %t.o -o %t.so -shared 2>&1 | FileCheck %s
+// CHECK: {{.*}}:(.dummy+0x0): has non-ABS reloc
+
+.globl _start
+_start:
+  nop
+
+.section .dummy
+  .long foo@gotpcrel

test/ELF/relocation-past-merge-end.s

 // REQUIRES: x86
 // RUN: llvm-mc %s -o %t.o -filetype=obj -triple=x86_64-pc-linux
 // RUN: not ld.lld %t.o -o %t.so -shared 2>&1 | FileCheck %s
-// CHECK: relocation-past-merge-end.s.tmp.o(.foo): entry is past the end of the section
+// CHECK: relocation-past-merge-end.s.tmp.o:(.foo): entry is past the end of the section
 
 .data
 .long .foo + 10
 .section  .foo,"aM",@progbits,4
 .quad 0