[xray] Add llvm-xray extract support for 32 bit ARM

Summary:
XRay works on 32-bit ARM but extract didn't support it.

See also another previous attempt in D77858.

Reviewers: MaskRay, dberris, johnislarry

Subscribers: kristof.beyls, hiraditya, danielkiss, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80185

1 files changed, 24 insertions, 9 deletions

diff --git a/llvm/lib/XRay/InstrumentationMap.cpp b/llvm/lib/XRay/InstrumentationMap.cpp
index 9db9692..de0a9e6 100644
--- a/llvm/lib/XRay/InstrumentationMap.cpp
+++ b/llvm/lib/XRay/InstrumentationMap.cpp
@@ -61,6 +61,7 @@ loadObj(StringRef Filename, object::OwningBinary<object::ObjectFile> &ObjFile,
   if ((!ObjFile.getBinary()->isELF() && !ObjFile.getBinary()->isMachO()) ||
       !(ObjFile.getBinary()->getArch() == Triple::x86_64 ||
         ObjFile.getBinary()->getArch() == Triple::ppc64le ||
+        ObjFile.getBinary()->getArch() == Triple::arm ||
         ObjFile.getBinary()->getArch() == Triple::aarch64))
     return make_error<StringError>(
         "File format not supported (only does ELF and Mach-O little endian "
@@ -115,7 +116,14 @@ loadObj(StringRef Filename, object::OwningBinary<object::ObjectFile> &ObjFile,
 
     for (const object::SectionRef &Section : Sections) {
       for (const object::RelocationRef &Reloc : Section.relocations()) {
-        if (SupportsRelocation && SupportsRelocation(Reloc.getType())) {
+        if (ObjFile.getBinary()->getArch() == Triple::arm) {
+          if (SupportsRelocation && SupportsRelocation(Reloc.getType())) {
+            Expected<uint64_t> ValueOrErr = Reloc.getSymbol()->getValue();
+            if (!ValueOrErr)
+              return ValueOrErr.takeError();
+            Relocs.insert({Reloc.getOffset(), Resolver(Reloc, *ValueOrErr, 0)});
+          }
+        } else if (SupportsRelocation && SupportsRelocation(Reloc.getType())) {
           auto AddendOrErr = object::ELFRelocationRef(Reloc).getAddend();
           auto A = AddendOrErr ? *AddendOrErr : 0;
           Expected<uint64_t> ValueOrErr = Reloc.getSymbol()->getValue();
@@ -133,12 +141,13 @@ loadObj(StringRef Filename, object::OwningBinary<object::ObjectFile> &ObjFile,
 
   // Copy the instrumentation map data into the Sleds data structure.
   auto C = Contents.bytes_begin();
-  static constexpr size_t ELF64SledEntrySize = 32;
+  bool Is32Bit = ObjFile.getBinary()->makeTriple().isArch32Bit();
+  size_t ELFSledEntrySize = Is32Bit ? 16 : 32;
 
-  if ((C - Contents.bytes_end()) % ELF64SledEntrySize != 0)
+  if ((C - Contents.bytes_end()) % ELFSledEntrySize != 0)
     return make_error<StringError>(
         Twine("Instrumentation map entries not evenly divisible by size of "
-              "an XRay sled entry in ELF64."),
+              "an XRay sled entry."),
         std::make_error_code(std::errc::executable_format_error));
 
   auto RelocateOrElse = [&](uint64_t Offset, uint64_t Address) {
@@ -151,20 +160,26 @@ loadObj(StringRef Filename, object::OwningBinary<object::ObjectFile> &ObjFile,
     return Address;
   };
 
-  const int WordSize = 8;
+  const int WordSize = Is32Bit ? 4 : 8;
   int32_t FuncId = 1;
   uint64_t CurFn = 0;
-  for (; C != Contents.bytes_end(); C += ELF64SledEntrySize) {
+  for (; C != Contents.bytes_end(); C += ELFSledEntrySize) {
     DataExtractor Extractor(
-        StringRef(reinterpret_cast<const char *>(C), ELF64SledEntrySize), true,
+        StringRef(reinterpret_cast<const char *>(C), ELFSledEntrySize), true,
         8);
     Sleds.push_back({});
     auto &Entry = Sleds.back();
     uint64_t OffsetPtr = 0;
     uint64_t AddrOff = OffsetPtr;
-    Entry.Address = RelocateOrElse(AddrOff, Extractor.getU64(&OffsetPtr));
+    if (Is32Bit)
+      Entry.Address = RelocateOrElse(AddrOff, Extractor.getU32(&OffsetPtr));
+    else
+      Entry.Address = RelocateOrElse(AddrOff, Extractor.getU64(&OffsetPtr));
     uint64_t FuncOff = OffsetPtr;
-    Entry.Function = RelocateOrElse(FuncOff, Extractor.getU64(&OffsetPtr));
+    if (Is32Bit)
+      Entry.Function = RelocateOrElse(FuncOff, Extractor.getU32(&OffsetPtr));
+    else
+      Entry.Function = RelocateOrElse(FuncOff, Extractor.getU64(&OffsetPtr));
     auto Kind = Extractor.getU8(&OffsetPtr);
     static constexpr SledEntry::FunctionKinds Kinds[] = {
         SledEntry::FunctionKinds::ENTRY, SledEntry::FunctionKinds::EXIT,