[LLD] [COFF] Add support for IMAGE_REL_ARM64_SECREL

[mstorsjo]

Summary

I never ran into this until lld-link started enabling debug output by default for the mingw mode. I haven't been able to verify that this actually behaves correctly, but this relocation is handled identically on all other architectures so far.

[ruiu]

LGTM

COFF/Chunks.cpp

void SectionChunk::applyRelARM64(uint8_t *Off, uint16_t Type, OutputSection *OS,
   switch (Type) {
   case IMAGE_REL_ARM64_PAGEBASE_REL21: applyArm64Addr(Off, S, P); break;
   case IMAGE_REL_ARM64_PAGEOFFSET_12A: applyArm64Imm(Off, S & 0xfff, 0); break;
   case IMAGE_REL_ARM64_PAGEOFFSET_12L: applyArm64Ldr(Off, S & 0xfff); break;
   case IMAGE_REL_ARM64_BRANCH26:       or32(Off, ((S - P) & 0x0FFFFFFC) >> 2); break;
   case IMAGE_REL_ARM64_ADDR32:         add32(Off, S + Config->ImageBase); break;
   case IMAGE_REL_ARM64_ADDR32NB:       add32(Off, S); break;
   case IMAGE_REL_ARM64_ADDR64:         add64(Off, S + Config->ImageBase); break;
+  case IMAGE_REL_ARM64_SECREL:         applySecRel(this, Off, OS, S); break;
   default:
     fatal("unsupported relocation type 0x" + Twine::utohexstr(Type));
   }
 }
 
 void SectionChunk::writeTo(uint8_t *Buf) const {
   if (!hasData())
     return;

test/COFF/arm64-relocs-imports.test

 # BEFORE:       5c:       20 1a 01 b0     adrp    x0, #36982784
 # BEFORE:       60:       00 fc 4f f9     ldr     x0, [x0, #8184]
 # BEFORE:       64:       e0 03 1f 2a     mov      w0, wzr
 # BEFORE:       68:       fe 07 41 f8     ldr     x30, [sp], #16
 # BEFORE:       6c:       c0 03 5f d6     ret
 # BEFORE:       70:       08 00 00 00     <unknown>
 # BEFORE:       74:       00 00 00 00     <unknown>
 # BEFORE:       78:       01 00 00 00     <unknown>
+# BEFORE:       7c:       01 00 00 00     <unknown>
 
 # AFTER: Disassembly of section .text:
 # AFTER:  140002000:      fe 0f 1f f8     str     x30, [sp, #-16]!
 # AFTER:  140002004:      e0 ff ff f0     adrp    x0, #-4096
 # AFTER:  140002008:      00 18 00 91     add     x0, x0, #6
-# AFTER:  14000200c:      1c 00 00 94     bl      #112
+# AFTER:  14000200c:      1d 00 00 94     bl      #116
 # AFTER:  140002010:      00 21 40 39     ldrb    w0, [x8, #8]
 # AFTER:  140002014:      00 11 40 79     ldrh    w0, [x8, #8]
 # AFTER:  140002018:      00 09 40 b9     ldr     w0, [x8, #8]
 # AFTER:  14000201c:      00 05 40 f9     ldr     x0, [x8, #8]
 # AFTER:  140002020:      00 21 00 39     strb    w0, [x8, #8]
 # AFTER:  140002024:      00 11 00 79     strh    w0, [x8, #8]
 # AFTER:  140002028:      00 09 00 b9     str     w0, [x8, #8]
 # AFTER:  14000202c:      00 05 00 f9     str     x0, [x8, #8]

 # AFTER:  14000205c:      00 00 00 b0     adrp    x0, #4096
 # AFTER:  140002060:      00 fc 47 f9     ldr     x0, [x0, #4088]
 # AFTER:  140002064:      e0 03 1f 2a     mov      w0, wzr
 # AFTER:  140002068:      fe 07 41 f8     ldr     x30, [sp], #16
 # AFTER:  14000206c:      c0 03 5f d6     ret
 # AFTER:  140002070:      10 10 00 40     <unknown>
 # AFTER:  140002074:      01 00 00 00     <unknown>
 # AFTER:  140002078:      09 10 00 00     <unknown>
-# AFTER:  14000207c:      10 00 00 b0     adrp    x16, #4096
-# AFTER:  140002080:      10 1e 40 f9     ldr     x16, [x16, #56]
-# AFTER:  140002084:      00 02 1f d6     br      x16
+# AFTER:  14000207c:      09 00 00 00     <unknown>
+# AFTER:  140002080:      10 00 00 b0     adrp    x16, #4096
+# AFTER:  140002084:      10 1e 40 f9     ldr     x16, [x16, #56]
+# AFTER:  140002088:      00 02 1f d6     br      x16
 
 --- !COFF
 header:
   Machine:         IMAGE_FILE_MACHINE_ARM64
   Characteristics: [  ]
 sections:
   - Name:            .text
     Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
     Alignment:       4
-    SectionData:     FE0F1FF80000009000080091000000940001403900014079000140B9000140F90001003900010079000100B9000100F90001403D0001407D000140BD000140FD0001C03D0001003D0001007D000100BD000100FD0001803D000540F9201A01B000FC4FF9E0031F2AFE0741F8C0035FD6080000000000000001000000
+    SectionData:     FE0F1FF80000009000080091000000940001403900014079000140B9000140F90001003900010079000100B9000100F90001403D0001407D000140BD000140FD0001C03D0001003D0001007D000100BD000100FD0001803D000540F9201A01B000FC4FF9E0031F2AFE0741F8C0035FD608000000000000000100000001000000
     Relocations:
       - VirtualAddress:  4
         SymbolName:      .Lstr
         Type:            IMAGE_REL_ARM64_PAGEBASE_REL21
       - VirtualAddress:  8
         SymbolName:      .Lstr
         Type:            IMAGE_REL_ARM64_PAGEOFFSET_12A
       - VirtualAddress:  12
Relocations:
         SymbolName:      .Lglobal0
         Type:            IMAGE_REL_ARM64_PAGEOFFSET_12L
       - VirtualAddress:  112
         SymbolName:      .Lglobal
         Type:            IMAGE_REL_ARM64_ADDR64
       - VirtualAddress:  120
         SymbolName:      .Lglobal
         Type:            IMAGE_REL_ARM64_ADDR32NB
+      - VirtualAddress:  124
+        SymbolName:      .Lglobal
+        Type:            IMAGE_REL_ARM64_SECREL
   - Name:            .data
     Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
     Alignment:       4
     SectionData:     ''
   - Name:            .bss
     Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
     Alignment:       4
     SectionData:     ''