[PATCH] D55817: [ELF][ARM] Process ARM build attributes of dynamic libraries.

[Igor Kudrin via Phabricator via llvm-commits]

ikudrin created this revision.
ikudrin added reviewers: ruiu, peter.smith, kettenis, grimar.
ikudrin added a project: lld.
Herald added subscribers: MaskRay, kristof.beyls, arichardson, javed.absar.
Herald added a reviewer: espindola.

This helps to detect incompatible settings between dynamic libraries and other input files.

Note that GOLD issues an error in that case, while LD ignores it.
However, I believe that it is better to be strict here.


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D55817

Files:
  ELF/InputFiles.cpp
  ELF/InputFiles.h
  test/ELF/arm-tag-vfp-args-errs.s


Index: test/ELF/arm-tag-vfp-args-errs.s
===================================================================
--- test/ELF/arm-tag-vfp-args-errs.s
+++ test/ELF/arm-tag-vfp-args-errs.s
@@ -3,12 +3,16 @@
 // RUN: llvm-mc -filetype=obj -triple=armv7a-none-linux-gnueabi %S/Inputs/arm-vfp-arg-vfp.s -o %tvfp.o
 // RUN: llvm-mc -filetype=obj -triple=armv7a-none-linux-gnueabi %S/Inputs/arm-vfp-arg-toolchain.s -o %ttoolchain.o
 // RUN: llvm-mc -filetype=obj -triple=armv7a-none-linux-gnueabi %s -o %t.o
+// RUN: ld.lld -shared %tbase.o -o %tbase.so
+// RUN: ld.lld -shared %tvfp.o -o %tvfp.so
 // RUN: not ld.lld %t.o %tbase.o %tvfp.o -o%t 2>&1 | FileCheck %s
 // RUN: not ld.lld %t.o %tbase.o %ttoolchain.o -o%t 2>&1 | FileCheck %s
 // RUN: not ld.lld %t.o %tvfp.o %tbase.o -o%t 2>&1 | FileCheck %s
 // RUN: not ld.lld %t.o %tvfp.o %ttoolchain.o -o%t 2>&1 | FileCheck %s
 // RUN: not ld.lld %t.o %ttoolchain.o %tbase.o -o%t 2>&1 | FileCheck %s
 // RUN: not ld.lld %t.o %ttoolchain.o %tvfp.o -o%t 2>&1 | FileCheck %s
+// RUN: not ld.lld %t.o %tbase.o %tvfp.so -o%t 2>&1 | FileCheck %s
+// RUN: not ld.lld %t.o %tbase.so %tvfp.o -o%t 2>&1 | FileCheck %s
 
 // CHECK: incompatible Tag_ABI_VFP_args
 	.arch armv7-a
Index: ELF/InputFiles.h
===================================================================
--- ELF/InputFiles.h
+++ ELF/InputFiles.h
@@ -321,6 +321,7 @@
 
   const Elf_Shdr *VersymSec = nullptr;
   const Elf_Shdr *VerdefSec = nullptr;
+  const Elf_Shdr *ARMAttributesSec = nullptr;
 
 public:
   std::vector<const Elf_Verdef *> Verdefs;
Index: ELF/InputFiles.cpp
===================================================================
--- ELF/InputFiles.cpp
+++ ELF/InputFiles.cpp
@@ -583,6 +583,16 @@
   }
 }
 
+template <class ELFT>
+static void processARMAttributesSection(const ELFFileBase<ELFT> *F,
+                                        const typename ELFT::Shdr &Sec) {
+  ARMAttributeParser Attributes;
+  ArrayRef<uint8_t> Contents = check(F->getObj().getSectionContents(&Sec));
+  Attributes.Parse(Contents, /*isLittle*/ Config->EKind == ELF32LEKind);
+  updateSupportedARMFeatures(Attributes);
+  updateARMVFPArgs(Attributes, F);
+}
+
 template <class ELFT>
 InputSectionBase *ObjFile<ELFT>::getRelocTarget(const Elf_Shdr &Sec) {
   uint32_t Idx = Sec.sh_info;
@@ -616,11 +626,7 @@
   case SHT_ARM_ATTRIBUTES: {
     if (Config->EMachine != EM_ARM)
       break;
-    ARMAttributeParser Attributes;
-    ArrayRef<uint8_t> Contents = check(this->getObj().getSectionContents(&Sec));
-    Attributes.Parse(Contents, /*isLittle*/ Config->EKind == ELF32LEKind);
-    updateSupportedARMFeatures(Attributes);
-    updateARMVFPArgs(Attributes, this);
+    processARMAttributesSection(this, Sec);
 
     // FIXME: Retain the first attribute section we see. The eglibc ARM
     // dynamic loaders require the presence of an attribute section for dlopen
@@ -880,6 +886,9 @@
     case SHT_DYNSYM:
       this->initSymtab(Sections, &Sec);
       break;
+    case SHT_ARM_ATTRIBUTES:
+      this->ARMAttributesSec = &Sec;
+      break;
     case SHT_DYNAMIC:
       DynamicSec = &Sec;
       break;
@@ -993,6 +1002,8 @@
 // than necessary, but you can easily understand the code if you wrap your
 // head around the data structure described above.
 template <class ELFT> void SharedFile<ELFT>::parseRest() {
+  if (this->ARMAttributesSec && Config->EMachine == EM_ARM)
+    processARMAttributesSection(this, *(this->ARMAttributesSec));
   Verdefs = parseVerdefs();                       // parse .gnu.version_d
   std::vector<uint32_t> Versyms = parseVersyms(); // parse .gnu.version
   ArrayRef<Elf_Shdr> Sections = CHECK(this->getObj().sections(), this);


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