Added file compatibility check to ELFDynObjParser::parseFile function

docs/userguide/documentation/linker_faq.rst

@@ -1302,6 +1302,29 @@ The following overlaps are detected by the linker.
 If the overlaps are known and you want to turn this behavior OFF, you can use
 *--no-check-sections* flag.
 
+Link errors
+-----------
+
+Why am I receiving the error 'cannot recognize the format of file YourObjectFile.o'. object format or given target machine (...) is incompatible.'?
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+**Fix:** Ensure that all object files being linked use the same object format
+and target architecture.
+
+**But what is the cause of the error?**
+
+A linker can only combine object files that are compatible with each other.
+This means every input file must match in:
+  * Object format (e.g. ELF)
+  * Target architecture (e.g. Hexagon)
+  * Endianness and ABI
+
+If any object file differs, the linker cannot interpret it correctly and will
+produce this error.
+
+**How to verify:** You can inspect the object file using by using tools like
+llvm-readelf.
+
 Input File to Linker
 =====================
 

include/eld/Diagnostics/DiagCommonKinds.inc

@@ -14,7 +14,7 @@
 DIAG(cannot_open_search_dir, DiagnosticEngine::Note,
      "can not open search directory `%0'")
 DIAG(err_no_inputs, DiagnosticEngine::Error, "no inputs")
-DIAG(err_unrecognized_input_file, DiagnosticEngine::Fatal,
+DIAG(err_unrecognized_input_file, DiagnosticEngine::Error,
      "cannot recognize the format of file `%0'. object format or given target "
      "machine (%1) is incompatible.")
 DIAG(err_cannot_find_namespec, DiagnosticEngine::Fatal,

lib/Readers/ELFDynObjParser.cpp

@@ -32,6 +32,11 @@ eld::Expected<bool> ELFDynObjParser::parseFile(InputFile &inputFile) {
 
   std::unique_ptr<ELFReaderBase> ELFReader = std::move(expReader.value());
 
+  eld::Expected<bool> expCompatibility = ELFReader->isCompatible();
+  ELDEXP_RETURN_DIAGENTRY_IF_ERROR(expCompatibility);
+  if (!expCompatibility.value())
+    return false;
+
   eld::Expected<bool> expCheckFlags = ELFReader->checkFlags();
 
   // FIXME: Linker should give some error if checkFlags return false.
@@ -42,7 +47,7 @@ eld::Expected<bool> ELFDynObjParser::parseFile(InputFile &inputFile) {
       if (!flagStr.empty()) {
         std::string flag = "[" + std::string(flagStr) + "]";
         layoutInfo->recordInputActions(LayoutInfo::Load, inputFile.getInput(),
-                                    flag);
+                                       flag);
       }
     }
   }

lib/Readers/ELFReader.cpp

@@ -427,7 +427,7 @@ eld::Expected<bool> ELFReader<ELFT>::isCompatible() const {
     return std::make_unique<plugin::DiagnosticEntry>(plugin::DiagnosticEntry(
         Diag::err_unrecognized_input_file,
         {inputFile.getInput()->getResolvedPath().native(),
-         config.targets().triple().str()}));
+         config.targets().getArch()}));
 
   eld::Expected<bool> expCheckFlags = checkFlags();
   ELDEXP_RETURN_DIAGENTRY_IF_ERROR(expCheckFlags);

test/AArch64/standalone/WrongArchObject/Inputs/1.yaml → test/Common/standalone/WrongArchObject/Inputs/1.yaml

@@ -2,8 +2,8 @@
 FileHeader:
   Class:           ELFCLASS32
   Data:            ELFDATA2LSB
-  Type:            ET_REL
-  Machine:         EM_386
+  Type:            [[TYPE=ET_REL]]
+  Machine:         EM_NONE
 Sections:
   - Name:            .text
     Type:            SHT_PROGBITS

test/Common/standalone/WrongArchObject/WrongArchInput.test

@@ -0,0 +1,11 @@
+RUN: %yaml2obj %p/Inputs/1.yaml -o %t.1.o
+RUN: %clang %clangopts -c %p/Inputs/2.c -o %t1.o
+RUN: %not %link %emulation %linkopts %t.1.o %t1.o -o %t2.out 2>&1 | %filecheck %s
+RUN: %ar cr %aropts %t1.a %t.1.o
+RUN: %not %link %emulation %linkopts %t1.o --whole-archive %t1.a -o %t3.out 2>&1 | %filecheck %s -check-prefix=ARCHIVE
+RUN: %yaml2obj %p/Inputs/1.yaml -DTYPE=ET_DYN -o %t.lib.so
+RUN: %not %link %emulation -Bdynamic %t1.o -L%p/Inputs %t.lib.so 2>&1 | %filecheck %s -check-prefix=DYNAMIC
+
+CHECK: Error: cannot recognize the format of file {{[` -\(\)_A-Za-z0-9.\\/:]+}}1.o'. object format or given target machine ({{[` -\(\)_A-Za-z0-9.\\/:]+}}) is incompatible.
+ARCHIVE: Error: cannot recognize the format of file {{[` -\(\)_A-Za-z0-9.\\/:]+}}.a'. object format or given target machine ({{[` -\(\)_A-Za-z0-9.\\/:]+}}) is incompatible.
+DYNAMIC: Error: cannot recognize the format of file {{[` -\(\)_A-Za-z0-9.\\/:]+}}lib.so'. object format or given target machine ({{[` -\(\)_A-Za-z0-9.\\/:]+}}) is incompatible.