[dwarf] Unify unknown dwarf enum formatting code

Summary:
We have had at least three pieces of code (in DWARFAbbreviationDeclaration,
DWARFAcceleratorTable and DWARFDie) that have hand-rolled support for
dumping unknown dwarf enum values. While not terrible, they are a bit
distracting and enable small differences to creep in (Unknown_ffff vs.
Unknown_0xffff). I ended up needing to add a fourth place
(DWARFVerifier), so it seems it would be a good time to centralize.

This patch creates an alternative to the XXXString dumping functions in
the BinaryFormat library, which formats an unknown value as
DW_TYPE_unknown_1234, instead of just an empty string. It is based on
the formatv function, as that allows us to avoid materializing the
string for unknown values (and because this way I don't have to invent a
name for the new functions :P).

In this patch I add formatters for dwarf attributes, forms, tags, and
index attributes as these are the ones in use currently, but adding
other enums is straight-forward.

Reviewers: dblaikie, JDevlieghere, aprantl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D44570

llvm-svn: 328090

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/unittests/BinaryFormat/DwarfTest.cpp b/llvm/unittests/BinaryFormat/DwarfTest.cpp
index c30910aa856..08a731f6174 100644
--- a/llvm/unittests/BinaryFormat/DwarfTest.cpp
+++ b/llvm/unittests/BinaryFormat/DwarfTest.cpp
@@ -9,6 +9,7 @@
 
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/FormatVariadic.h"
 #include "gtest/gtest.h"
 
 using namespace llvm;
@@ -192,4 +193,14 @@ TEST(DwarfTest, FixedFormSizes) {
   EXPECT_EQ(*RefSize, 8);
 }
 
+TEST(DwarfTest, format_provider) {
+  EXPECT_EQ("DW_AT_name", formatv("{0}", DW_AT_name).str());
+  EXPECT_EQ("DW_AT_unknown_3fff", formatv("{0}", DW_AT_hi_user).str());
+  EXPECT_EQ("DW_FORM_addr", formatv("{0}", DW_FORM_addr).str());
+  EXPECT_EQ("DW_FORM_unknown_1f00", formatv("{0}", DW_FORM_lo_user).str());
+  EXPECT_EQ("DW_IDX_compile_unit", formatv("{0}", DW_IDX_compile_unit).str());
+  EXPECT_EQ("DW_IDX_unknown_3fff", formatv("{0}", DW_IDX_hi_user).str());
+  EXPECT_EQ("DW_TAG_compile_unit", formatv("{0}", DW_TAG_compile_unit).str());
+  EXPECT_EQ("DW_TAG_unknown_ffff", formatv("{0}", DW_TAG_hi_user).str());
+}
 } // end namespace