[PATCH] D103815: [LLD][ELF] Fix PT_LOAD program header creation for NO_LOAD sections

[Konstantin Schwarz via Phabricator via llvm-commits]

kschwarz added inline comments.


================
Comment at: lld/test/ELF/linkerscript/nobits-offset.s:22
 # CHECK:      Type Offset   VirtAddr           PhysAddr           FileSiz  MemSiz   Flg Align
-# CHECK-NEXT: LOAD 0x000400 0x0000000000000400 0x0000000000000400 0x000000 0x000001 RW  0x1000
+# CHECK-NEXT: LOAD 0x001000 0x0000000000000000 0x0000000000000000 0x000000 0x000001 R   0x1000
+# CHECK-NEXT: LOAD 0x001400 0x0000000000000400 0x0000000000000400 0x000000 0x000001 RW  0x1000
----------------
Independent from this change, GNU ld assigns `WA` section flags to output sections defined as

```
.sec1 (NOLOAD) : { . += 1; }
```
, while ld.lld assigns `A`. Is this intended?

This has also an effect on the number of program headers we create. In the test, the `bss` section has `WA`
flags, thus getting its own header.


================
Comment at: lld/test/ELF/linkerscript/noload.s:13
 # CHECK:      Type Offset   VirtAddr           PhysAddr
+# CHECK-NEXT: LOAD 0x001000 0x0000000000000000 0x0000000000000000
 # CHECK-NEXT: LOAD 0x001000 0x0000000000020000 0x0000000000020000
----------------
GNU ld creates the following program headers:

```
  LOAD           0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x001000 RW  0x1000
  LOAD           0x000000 0x0000000000010000 0x0000000000010000 0x000000 0x001001 RW  0x1000
  LOAD           0x001000 0x0000000000020000 0x0000000000020000 0x000001 0x000001 R E 0x1000
```

Should we create a new header whenever a section has an `addrExpr` set, similar to our condition for lmaExpr?

GNU ld will only create a new header if the current section is placed at a discontiguous address.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103815/new/

https://reviews.llvm.org/D103815