[RISCV] Delete deprecated attributes

[zeng-xiao]

Summary

As described in riscv-elf-psabi, some attributes in risc-v have been deprecated.
The relevant link is: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/commit/1b197a9f480ebc37835f8ef101a584e8a51fbe23

[zeng-xiao]

[RISCV] Delete deprecated attributes

Update test case: riscv-attributes.s

[MaskRay]

These are deprecated, not removed. lld needs to handle old object files with these attributes. The integrated assembler needs to support the syntax in case there are files using these directives.
I think we can only remove them when the compatibility with these object files/assembly files are deemed unnecessary. I am not sure when we claim to do that.

[zeng-xiao]

In D158575#4609157, @MaskRay wrote:

These are deprecated, not removed. lld needs to handle old object files with these attributes. The integrated assembler needs to support the syntax in case there are files using these directives.
I think we can only remove them when the compatibility with these object files/assembly files are deemed unnecessary. I am not sure when we claim to do that.

Okay, I understand what you mean. To be compatible with old elf files, these attributes in risc-v cannot be removed at this time. Perhaps one day in the future, we need to do this work.
This is my first llvm patch, and there will be other patches in the future.
Thank you, Professor Song's comment.
By the way, I am your fan. It's really surprising to have a conversation with you in this way.

[zeng-xiao]

Updating D158575: [RISCV] Delete deprecated attributes

[zeng-xiao]

Updating D158575: [RISCV] Delete deprecated attributes

[MaskRay]

Updating D158575: [RISCV] Delete deprecated attributes

I think this patch should be abandoned. We need test coverage for the assembler and the linker. When I added the support to lld/ELF, I intentionally kept the deprecated cases

  // Attributes which use the default handling.
case RISCVAttrs::PRIV_SPEC:
case RISCVAttrs::PRIV_SPEC_MINOR:
case RISCVAttrs::PRIV_SPEC_REVISION:

to make it clear we need to support object files using them.

[zeng-xiao]

In D158575#4610925, @MaskRay wrote:

Updating D158575: [RISCV] Delete deprecated attributes

I think this patch should be abandoned. We need test coverage for the assembler and the linker. When I added the support to lld/ELF, I intentionally kept the deprecated cases

  // Attributes which use the default handling.
case RISCVAttrs::PRIV_SPEC:
case RISCVAttrs::PRIV_SPEC_MINOR:
case RISCVAttrs::PRIV_SPEC_REVISION:

to make it clear we need to support object files using them.

Okay, thank you. I will discard this patch.

lld/ELF/Arch/RISCV.cpp

for (const auto &tag : attributesTags) {
         // String attributes.
       case RISCVAttrs::ARCH:
         if (auto s = parser.getAttributeString(tag.attr)) {
           hasArch = true;
           mergeArch(exts, xlen, sec, *s);
         }
         continue;
 
-        // Attributes which use the default handling.
-      case RISCVAttrs::PRIV_SPEC:
-      case RISCVAttrs::PRIV_SPEC_MINOR:
-      case RISCVAttrs::PRIV_SPEC_REVISION:
+      default:
         break;
       }
 
-      // Fallback for deprecated priv_spec* and other unknown attributes: retain
-      // the attribute if all input sections agree on the value. GNU ld uses 0
-      // and empty strings as default values which are not dumped to the output.
+      // Fallback for other unknown attributes: retain the attribute if all
+      // input sections agree on the value. GNU ld uses 0 and empty strings
+      // as default values which are not dumped to the output.
       // TODO Adjust after resolution to
       // https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/352
       if (tag.attr % 2 == 0) {
         if (auto i = parser.getAttributeValue(tag.attr)) {
           auto r = merged.intAttr.try_emplace(tag.attr, *i);
           if (!r.second && r.first->second != *i)
             r.first->second = 0;
         }

lld/test/ELF/riscv-attributes.s

 # RUN: ld.lld -e 0 --fatal-warnings a.o unaligned_access_0.o -o unaligned_access_0
 # RUN: llvm-readobj -A unaligned_access_0 | FileCheck /dev/null --implicit-check-not='TagName: unaligned_access'
 
 ## Differing stack_align values lead to an error.
 # RUN: llvm-mc -filetype=obj -triple=riscv64 diff_stack_align.s -o diff_stack_align.o
 # RUN: not ld.lld a.o b.o c.o diff_stack_align.o -o /dev/null 2>&1 | FileCheck %s --check-prefix=STACK_ALIGN --implicit-check-not=error:
 # STACK_ALIGN: error: diff_stack_align.o:(.riscv.attributes) has stack_align=32 but a.o:(.riscv.attributes) has stack_align=16
 
-## The deprecated priv_spec is not handled as GNU ld does.
-## Differing priv_spec attributes lead to an absent attribute.
-# RUN: llvm-mc -filetype=obj -triple=riscv64 diff_priv_spec.s -o diff_priv_spec.o
-# RUN: ld.lld -e 0 --fatal-warnings a.o b.o c.o diff_priv_spec.o -o diff_priv_spec
-# RUN: llvm-readobj -A diff_priv_spec | FileCheck /dev/null --implicit-check-not='TagName: priv_spec'
-
 ## Unknown tags currently lead to warnings.
 # RUN: llvm-mc -filetype=obj -triple=riscv64 unknown13.s -o unknown13.o
 # RUN: llvm-mc -filetype=obj -triple=riscv64 unknown13a.s -o unknown13a.o
 # RUN: ld.lld -e 0 unknown13.o unknown13.o unknown13a.o -o unknown13 2>&1 | FileCheck %s --check-prefix=UNKNOWN13 --implicit-check-not=warning:
 # UNKNOWN13-COUNT-2: warning: unknown13.o:(.riscv.attributes): invalid tag 0xd at offset 0x10
 # UNKNOWN13:         warning: unknown13a.o:(.riscv.attributes): invalid tag 0xd at offset 0x10
 
 # RUN: llvm-mc -filetype=obj -triple=riscv64 unknown22.s -o unknown22.o

 # CHECK2-NEXT:       }
 # CHECK2-NEXT:       Attribute {
 # CHECK2-NEXT:         Tag: 6
 # CHECK2-NEXT:         Value: 1
 # CHECK2-NEXT:         TagName: unaligned_access
 # CHECK2-NEXT:         Description: Unaligned access
 # CHECK2-NEXT:       }
 # CHECK2-NEXT:       Attribute {
-# CHECK2-NEXT:         Tag: 8
-# CHECK2-NEXT:         TagName: priv_spec
-# CHECK2-NEXT:         Value: 2
-# CHECK2-NEXT:       }
-# CHECK2-NEXT:       Attribute {
-# CHECK2-NEXT:         Tag: 10
-# CHECK2-NEXT:         TagName: priv_spec_minor
-# CHECK2-NEXT:         Value: 2
-# CHECK2-NEXT:       }
-# CHECK2-NEXT:       Attribute {
 # CHECK2-NEXT:         Tag: 5
 # CHECK2-NEXT:         TagName: arch
 # CHECK2-NEXT:         Value: rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zkt1p0_zve32f1p0_zve32x1p0_zvl32b1p0{{$}}
 # CHECK2-NEXT:       }
 # CHECK2-NEXT:     }
 # CHECK2-NEXT:   }
 # CHECK2-NEXT: }
 

 #--- a.s
 .attribute stack_align, 16
 .attribute arch, "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0"
 .attribute unaligned_access, 0
 
 #--- b.s
 .attribute stack_align, 16
 .attribute arch, "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0"
-.attribute priv_spec, 2
-.attribute priv_spec_minor, 2
 
 #--- c.s
 .attribute stack_align, 16
 .attribute arch, "rv64i2p1_f2p2_zkt1p0_zve32f1p0_zve32x1p0_zvl32b1p0"
 .attribute unaligned_access, 1
-.attribute priv_spec, 2
-.attribute priv_spec_minor, 2
 
 #--- unrecognized_ext1.s
 # UNRECOGNIZED_EXT1:      BuildAttributes {
 # UNRECOGNIZED_EXT1-NEXT:   FormatVersion: 0x41
 # UNRECOGNIZED_EXT1-NEXT:   Section 1 {
 # UNRECOGNIZED_EXT1-NEXT:     SectionLength: 30
 # UNRECOGNIZED_EXT1-NEXT:     Vendor: riscv
 # UNRECOGNIZED_EXT1-NEXT:     Tag: Tag_File (0x1)

 .Lend:
 
 #--- unaligned_access_0.s
 .attribute unaligned_access, 0
 
 #--- diff_stack_align.s
 .attribute stack_align, 32
 
-#--- diff_priv_spec.s
-.attribute priv_spec, 3
-.attribute priv_spec_minor, 3
-
 #--- unknown13.s
 .attribute 13, "0"
 #--- unknown13a.s
 .attribute 13, "1"
 
 #--- unknown22.s
 .attribute 22, 1
 #--- unknown22a.s
 .attribute 22, 2

llvm/include/llvm/Support/RISCVAttributes.h

 
 const TagNameMap &getRISCVAttributeTags();
 
 enum AttrType : unsigned {
   // Attribute types in ELF/.riscv.attributes.
   STACK_ALIGN = 4,
   ARCH = 5,
   UNALIGNED_ACCESS = 6,
-  PRIV_SPEC = 8,
-  PRIV_SPEC_MINOR = 10,
-  PRIV_SPEC_REVISION = 12,
 };
 
 enum StackAlign { ALIGN_4 = 4, ALIGN_16 = 16 };
 
 enum { NOT_ALLOWED = 0, ALLOWED = 1 };
 
 } // namespace RISCVAttrs
 } // namespace llvm
 
 #endif

llvm/lib/Support/RISCVAttributeParser.cpp

 
 const RISCVAttributeParser::DisplayHandler
     RISCVAttributeParser::displayRoutines[] = {
         {
             RISCVAttrs::ARCH,
             &ELFAttributeParser::stringAttribute,
         },
         {
-            RISCVAttrs::PRIV_SPEC,
-            &ELFAttributeParser::integerAttribute,
-        },
-        {
-            RISCVAttrs::PRIV_SPEC_MINOR,
-            &ELFAttributeParser::integerAttribute,
-        },
-        {
-            RISCVAttrs::PRIV_SPEC_REVISION,
-            &ELFAttributeParser::integerAttribute,
-        },
-        {
             RISCVAttrs::STACK_ALIGN,
             &RISCVAttributeParser::stackAlign,
         },
         {
             RISCVAttrs::UNALIGNED_ACCESS,
             &RISCVAttributeParser::unalignedAccess,
         }};
 

llvm/lib/Support/RISCVAttributes.cpp

 
 using namespace llvm;
 using namespace llvm::RISCVAttrs;
 
 static constexpr TagNameItem tagData[] = {
     {STACK_ALIGN, "Tag_stack_align"},
     {ARCH, "Tag_arch"},
     {UNALIGNED_ACCESS, "Tag_unaligned_access"},
-    {PRIV_SPEC, "Tag_priv_spec"},
-    {PRIV_SPEC_MINOR, "Tag_priv_spec_minor"},
-    {PRIV_SPEC_REVISION, "Tag_priv_spec_revision"},
 };
 
 constexpr TagNameMap RISCVAttributeTags{tagData};
 const TagNameMap &llvm::RISCVAttrs::getRISCVAttributeTags() {
   return RISCVAttributeTags;
 }

llvm/test/MC/RISCV/attribute.s

 .attribute stack_align, 16
 # CHECK: attribute      4, 16
 
 .attribute arch, "rv32i2p1_m2p0_a2p1_c2p0"
 # CHECK: attribute      5, "rv32i2p1_m2p0_a2p1_c2p0"
 
 .attribute unaligned_access, 0
 # CHECK: attribute      6, 0
-
-.attribute priv_spec, 2
-# CHECK: attribute      8, 2
-
-.attribute priv_spec_minor, 0
-# CHECK: attribute      10, 0
-
-.attribute priv_spec_revision, 0
-# CHECK: attribute      12, 0

llvm/test/MC/RISCV/invalid-attribute.s

 # CHECK: [[@LINE-1]]:18: error: invalid arch name 'rv32i2p1_y2p0', invalid standard user-level extension 'y'
 
 .attribute stack_align, "16"
 # CHECK: [[@LINE-1]]:25: error: expected numeric constant
 
 .attribute unaligned_access, "0"
 # CHECK: [[@LINE-1]]:30: error: expected numeric constant
 
-.attribute priv_spec, "2"
-# CHECK: [[@LINE-1]]:23: error: expected numeric constant
-
-.attribute priv_spec_minor, "0"
-# CHECK: [[@LINE-1]]:29: error: expected numeric constant
-
-.attribute priv_spec_revision, "0"
-# CHECK: [[@LINE-1]]:32: error: expected numeric constant
-
 .attribute arch, 30
 # CHECK: [[@LINE-1]]:18: error: expected string constant

llvm/test/tools/llvm-readobj/ELF/RISCV/attribute.s

 # CHECK-OBJ-NEXT: TagName: arch
 # CHECK-OBJ-NEXT: Value: rv32i2p1_m2p0_a2p1_c2p0
 
 .attribute  Tag_unaligned_access, 0
 # CHECK-OBJ:      Tag: 6
 # CHECK-OBJ-NEXT: Value: 0
 # CHECK-OBJ-NEXT: TagName: unaligned_access
 # CHECK-OBJ-NEXT: Description: No unaligned access
-
-.attribute  Tag_priv_spec, 2
-# CHECK-OBJ:      Tag: 8
-# CHECK-OBJ-NEXT: TagName: priv_spec
-# CHECK-OBJ-NEXT: Value: 2
-
-.attribute  Tag_priv_spec_minor, 0
-# CHECK-OBJ:      Tag: 10
-# CHECK-OBJ-NEXT: TagName: priv_spec_minor
-# CHECK-OBJ-NEXT: Value: 0
-
-.attribute  Tag_priv_spec_revision, 0
-# CHECK-OBJ:      Tag: 12
-# CHECK-OBJ-NEXT: TagName: priv_spec_revision
-# CHECK-OBJ-NEXT: Value: 0