[MC] Add section flag 'l' for SHF_X86_64_LARGE

[MaskRay]

This should be disabled for non-x86-64 triples.

[aeubanks]

In D148358#4269238, @MaskRay wrote:

This should be disabled for non-x86-64 triples.

if you look above my change, there are other arch-specific flags that aren't gated behind the assembly arch, this is consistent with that

[MaskRay]

In D148358#4269278, @aeubanks wrote:

In D148358#4269238, @MaskRay wrote:

This should be disabled for non-x86-64 triples.

if you look above my change, there are other arch-specific flags that aren't gated behind the assembly arch, this is consistent with that

I'm working on a patch to add errors...

[aeubanks]

rebase, don't allow for for non-x86_64

[MaskRay]

llvm/test/MC/ELF/section-flags-unknown.s

1

This will need a REQUIRES:.

llvm/lib/MC/MCParser/ELFAsmParser.cpp

for (char i : flagsStr) {
     case 's':
       if (TT.getArch() != Triple::hexagon)
         return -1U;
       flags |= ELF::SHF_HEX_GPREL;
       break;
     case 'G':
       flags |= ELF::SHF_GROUP;
       break;
+    case 'l':
+      if (TT.getArch() != Triple::x86_64)
+        return -1U;
+      flags |= ELF::SHF_X86_64_LARGE;
+      break;
     case 'R':
       if (TT.isOSSolaris())
         flags |= ELF::SHF_SUNW_NODISCARD;
       else
         flags |= ELF::SHF_GNU_RETAIN;
       break;
     case '?':
       *UseLastGroup = true;

llvm/test/MC/ELF/section-flags-unknown.s

 ## Some section flags are processor-specific. Reject them for other targets.
-# RUN: not llvm-mc -triple=x86_64 %s -o /dev/null 2>&1 | FileCheck %s --implicit-check-not=error:
+# RUN: not llvm-mc -triple=riscv32 %s -o /dev/null 2>&1 | FileCheck %s --implicit-check-not=error:
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:34: error: unknown flag
 .section XCORE_SHF_CP_SECTION,"c",@progbits
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:34: error: unknown flag
 .section XCORE_SHF_CP_SECTION,"d",@progbits
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:27: error: unknown flag
 .section SHF_HEX_GPREL,"s",@progbits
 
 # CHECK: {{.*}}.s:[[# @LINE+1]]:30: error: unknown flag
 .section SHF_ARM_PURECODE,"y",@progbits
+
+# CHECK: {{.*}}.s:[[# @LINE+1]]:30: error: unknown flag
+.section SHF_X86_64_LARGE,"l",@progbits

llvm/test/MC/ELF/section.s

 // CHECK:          Name: .tbss.foo
 // CHECK-NEXT:     Type: SHT_NOBITS
 // CHECK-NEXT:     Flags [
 // CHECK-NEXT:       SHF_ALLOC
 // CHECK-NEXT:       SHF_TLS
 // CHECK-NEXT:       SHF_WRITE
 // CHECK-NEXT:     ]
 
+.section .large,"l"
+// CHECK:        Section {
+// CHECK:          Name: .large
+// CHECK-NEXT:     Type: SHT_PROGBITS
+// CHECK-NEXT:     Flags [
+// CHECK-NEXT:       SHF_X86_64_LARGE
+// CHECK-NEXT:     ]
+
 // Test SHT_LLVM_ODRTAB
 
 .section .odrtab,"e",@llvm_odrtab
 // ASM: .section .odrtab,"e",@llvm_odrtab
 
 // CHECK:        Section {
 // CHECK:          Name: .odrtab
 // CHECK-NEXT:     Type: SHT_LLVM_ODRTAB