[LLD][ELF] - Improve "sh_addralign is not a power of 2" diagnostics.

[grimar]

Summary

This patch removes the precompiled binary from inputs, replacing it with a YAML.
And teaches LLD to report a section name in case of such error.

[grimar]

It might help for https://github.com/ClangBuiltLinux/linux/issues/218 hopefully.

[ruiu]

LGTM

ELF/InputSection.cpp

79

I think " section" is now redundant and should be removed.

ELF/InputSection.cpp

InputSectionBase::InputSectionBase(InputFile *File, uint64_t Flags,
 
   NumRelocations = 0;
   AreRelocsRela = false;
 
   // The ELF spec states that a value of 0 means the section has
   // no alignment constraits.
   uint32_t V = std::max<uint64_t>(Alignment, 1);
   if (!isPowerOf2_64(V))
-    fatal(toString(File) + ": section sh_addralign is not a power of 2");
+    fatal(toString(this) + ": section sh_addralign is not a power of 2");
   this->Alignment = V;
 
   // In ELF, each section can be compressed by zlib, and if compressed,
   // section name may be mangled by appending "z" (e.g. ".zdebug_info").
   // If that's the case, demangle section name so that we can handle a
   // section as if it weren't compressed.
   if ((Flags & SHF_COMPRESSED) || Name.startswith(".zdebug")) {
     if (!zlib::isAvailable())

test/ELF/invalid/section-alignment2.s

-## section-alignment-notpow2.elf has section alignment
-## 0xFFFFFFFF which is not a power of 2.
-# RUN: not ld.lld %p/Inputs/section-alignment-notpow2.elf -o /dev/null 2>&1 | \
-# RUN:   FileCheck %s
-# CHECK: section sh_addralign is not a power of 2
+# RUN: yaml2obj %s -o %t.o
+# RUN: not ld.lld %t.o -o %tout 2>&1 | FileCheck %s
+
+# CHECK: error: {{.*}}.o:(.text): section sh_addralign is not a power of 2
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x3