[DWARF] Refactor RelocVisitor and fix computation of SHT_RELA-typed relocation entries

Summary:
getRelocatedValue may compute incorrect value for SHT_RELA-typed relocation entries.

// DWARFDataExtractor.cpp
uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
...
  // This formula is correct for REL, but may be incorrect for RELA if the value
  // stored in the location (getUnsigned(Off, Size)) is not zero.
  return getUnsigned(Off, Size) + Rel->Value;

In this patch, we

* refactor these visit* functions to include a new parameter `uint64_t A`.
  Since these visit* functions are no longer used as visitors, rename them to resolve*.
  + REL: A is used as the addend. A is the value stored in the location where the
    relocation applies: getUnsigned(Off, Size)
  + RELA: The addend encoded in RelocationRef is used, e.g. getELFAddend(R)
* and add another set of supports* functions to check if a given relocation type is handled.
  DWARFObjInMemory uses them to fail early.

Reviewers: echristo, dblaikie

Reviewed By: echristo

Subscribers: mgorny, aprantl, aheejin, fedor.sergeev, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57939

llvm-svn: 356729
diff --git a/llvm/test/Object/invalid.test b/llvm/test/Object/invalid.test
index 6f3ab2a..a2650b8 100644
--- a/llvm/test/Object/invalid.test
+++ b/llvm/test/Object/invalid.test
@@ -3,7 +3,7 @@
 RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-zero-size.elf 2>&1 | FileCheck %s
 CHECK: Invalid data was encountered while parsing the file
 
-RUN: not llvm-dwarfdump %p/Inputs/invalid-bad-rel-type.elf 2>&1 | FileCheck --check-prefix=RELA %s
+RUN: not llvm-dwarfdump -debug-line %p/Inputs/invalid-bad-rel-type.elf 2>&1 | FileCheck --check-prefix=RELA %s
 RELA: Section is not SHT_RELA
 
 RUN: not llvm-objdump -s %p/Inputs/invalid-strtab-non-null.elf 2>&1 | FileCheck --check-prefix=NON-NULL %s