[RISCV] Add ELFObjectFileBase::getRISCVFeatures let llvm-objdump could get RISCV target feature

[shiva0217]

Summary

llvm-objdump could get C feature by ELF::EF_RISCV_RVC e_flag, so then we don't add -mattr=+c on the command line.

[asb]

Nice improvement - looks good to me. Thanks!

[asb]

Looks like there are two more test files you can update to not pass -mattr=+c to llvm-objdump:

• cnop.s
• fixups-compressed.s

Could you please update those too when you commit.

include/llvm/Object/ELFObjectFile.h

public:
   static bool classof(const Binary *v) { return v->isELF(); }
 
   SubtargetFeatures getFeatures() const override;
 
   SubtargetFeatures getMIPSFeatures() const;
 
   SubtargetFeatures getARMFeatures() const;
 
+  SubtargetFeatures getRISCVFeatures() const;
+
   void setARMSubArch(Triple &TheTriple) const override;
 };
 
 class ELFSectionRef : public SectionRef {
 public:
   ELFSectionRef(const SectionRef &B) : SectionRef(B) {
     assert(isa<ELFObjectFileBase>(SectionRef::getObject()));
   }

lib/Object/ELFObjectFile.cpp

case ARMBuildAttrs::AllowDIVExt:
       Features.AddFeature("hwdiv-arm");
       break;
     }
   }
 
   return Features;
 }
 
+SubtargetFeatures ELFObjectFileBase::getRISCVFeatures() const {
+  SubtargetFeatures Features;
+  unsigned PlatformFlags;
+  getPlatformFlags(PlatformFlags);
+
+  if (PlatformFlags & ELF::EF_RISCV_RVC) {
+    Features.AddFeature("c");
+  }
+
+  return Features;
+}
+
 SubtargetFeatures ELFObjectFileBase::getFeatures() const {
   switch (getEMachine()) {
   case ELF::EM_MIPS:
     return getMIPSFeatures();
   case ELF::EM_ARM:
     return getARMFeatures();
+  case ELF::EM_RISCV:
+    return getRISCVFeatures();
   default:
     return SubtargetFeatures();
   }
 }
 
 // FIXME Encode from a tablegen description or target parser.
 void ELFObjectFileBase::setARMSubArch(Triple &TheTriple) const {
   if (TheTriple.getSubArch() != Triple::NoSubArch)

test/MC/RISCV/rv32c-only-valid.s

 # RUN: llvm-mc -triple=riscv32 -mattr=+c -riscv-no-aliases -show-encoding < %s \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+c -riscv-no-aliases < %s \
-# RUN:     | llvm-objdump -mattr=+c -d - | FileCheck -check-prefix=CHECK-INST %s
+# RUN:     | llvm-objdump -d - | FileCheck -check-prefix=CHECK-INST %s
 # RUN: not llvm-mc -triple riscv32 \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN: not llvm-mc -triple riscv64 -mattr=+c \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 
 # CHECK-INST: c.jal    2046
 # CHECK: encoding: [0xfd,0x2f]
 # CHECK-NO-EXT:  error: instruction use requires an option to be enabled
 c.jal    2046

test/MC/RISCV/rv32c-valid.s

 # RUN: llvm-mc -triple=riscv32 -mattr=+c -riscv-no-aliases -show-encoding < %s \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -triple=riscv64 -mattr=+c -riscv-no-aliases -show-encoding < %s \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple riscv32 -mattr=+c < %s \
-# RUN:     | llvm-objdump -mattr=+c -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple riscv64 -mattr=+c < %s \
-# RUN:     | llvm-objdump -mattr=+c -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 
 # TODO: more exhaustive testing of immediate encoding.
 
 # CHECK-INST: c.lwsp  ra, 0(sp)
 # CHECK: encoding: [0x82,0x40]
 c.lwsp  ra, 0(sp)
 # CHECK-INST: c.swsp  ra, 252(sp)

test/MC/RISCV/rv32dc-valid.s

 # RUN: llvm-mc %s -triple=riscv32 -mattr=+c,+d -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+c,+d < %s \
-# RUN:     | llvm-objdump -mattr=+c,+d -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -mattr=+d -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 # RUN: not llvm-mc -triple riscv32 -mattr=+c\
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN: | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN:     not llvm-mc -triple riscv32 \
 # RUN: -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 

test/MC/RISCV/rv32fc-valid.s

 # RUN: llvm-mc %s -triple=riscv32 -mattr=+c,+f -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple=riscv32 -mattr=+c,+f < %s \
-# RUN:     | llvm-objdump -mattr=+c,+f -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -mattr=+f -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 # RUN: not llvm-mc -triple riscv32 -mattr=+c \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN: not llvm-mc -triple riscv32 \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN: not llvm-mc -triple riscv64 -mattr=+c,+f \

test/MC/RISCV/rv64c-valid.s

 # RUN: llvm-mc -triple=riscv64 -mattr=+c -riscv-no-aliases -show-encoding < %s \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple riscv64 -mattr=+c < %s \
-# RUN:     | llvm-objdump -mattr=+c -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 # RUN: not llvm-mc -triple riscv64 \
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN: not llvm-mc -triple riscv32 -mattr=+c\
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s
 

test/MC/RISCV/rv64dc-valid.s

 # RUN: llvm-mc %s -triple=riscv64 -mattr=+c,+d -riscv-no-aliases -show-encoding \
 # RUN:     | FileCheck -check-prefixes=CHECK,CHECK-INST %s
 # RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c,+d < %s \
-# RUN:     | llvm-objdump -mattr=+c,+d -riscv-no-aliases -d - \
+# RUN:     | llvm-objdump -mattr=+d -riscv-no-aliases -d - \
 # RUN:     | FileCheck -check-prefix=CHECK-INST %s
 # RUN: not llvm-mc -triple riscv64 -mattr=+c\
 # RUN:     -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN: | FileCheck -check-prefixes=CHECK-NO-EXT %s
 # RUN:     not llvm-mc -triple riscv64 \
 # RUN: -riscv-no-aliases -show-encoding < %s 2>&1 \
 # RUN:     | FileCheck -check-prefixes=CHECK-NO-EXT %s