[LLD][ELF] Add linker script generated data to non-contiguous relro test [NFC].

[peter.smith]

Summary

Adapted from an example in PR35478. If in the future we are going to ignore zero sized sections we need to account for linker scripts with location counter expressions or data creating functions such as BYTE. These linker script commands may be evaluated late on so testing early for OutputSection size will miss them.

This should only be committed once the revert of r318924 has been done (D40710).

[jhenderson]

test/ELF/relro-non-contiguous.s

27–28

I feel like these should be in two separate links. By combining the two, if one is correctly seen as influencing the size, but not the other, we won't notice.

[peter.smith]

Thanks for the comment, I've uploaded a new diff that tests each case individually.

[peter.smith]

This is almost exactly what I added as
test/ELF/relro-non-contiguous-script-data.s.

Would you mind rebasing this to add the BYTE case there instead?

Sorry,
Rafael

Sure I'll just commit that as it will be just a small addition to the existing test.

test/ELF/relro-non-contiguous.s

+// REQUIRES: x86
 // RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/shared.s -o %t.o
 // RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %p/Inputs/copy-in-shared.s -o %t2.o
 // RUN: ld.lld -shared %t.o %t2.o -o %t.so
 
 // Place the .got.plt (non relro) immediately after .dynamic. This is the
 // reverse order of the non-linker script case. The linker created .bss.rel.ro
 // section will be placed after .got.plt causing the relro to be non-contiguous.
 // RUN: echo "SECTIONS { \
 // RUN: .dynamic : { *(.dynamic) } \
 // RUN: .got.plt : { *(.got.plt) } \
 // RUN: } " > %t.script
 // RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t3.o
 
 // Expect error for non-contiguous relro
 // RUN: not ld.lld %t3.o %t.so -z relro -o %t --script=%t.script 2>&1 | FileCheck %s
 // No error when we do not request relro.
 // RUN: ld.lld %t3.o %t.so -z norelro -o %t --script=%t.script
-// REQUIRES: x86
 
 // CHECK: error: section: .bss.rel.ro is not contiguous with other relro sections
+
+// Insert a linkerscript command generating non-relro inbetween relro, these
+// may not have been evaluated by the time we calculate relro. This test is to
+// guard against skipping past non zero sized sections incorrectly.
+// RUN: echo "SECTIONS { \
+// RUN: .got.plt : { *(.got.plt) } \
+// RUN: .nonempty : { BYTE(1); *(.empty) } \
+// RUN: .dynamic : { *(.dynamic) } \
+// RUN: } " > %t.script2
+// RUN: not ld.lld %t3.o %t.so -z relro -o %t --script=%t.script2 2>&1 | FileCheck -check-prefix=CHECK-DYNAMIC %s
+
+// RUN: echo "SECTIONS { \
+// RUN: .got.plt : { *(.got.plt) } \
+// RUN: .nonempty : {  . = . + 3 ; *(.empty) } \
+// RUN: .dynamic : { *(.dynamic) } \
+// RUN: } " > %t.script3
+// RUN: not ld.lld %t3.o %t.so -z relro -o %t --script=%t.script3 2>&1 | FileCheck -check-prefix=CHECK-DYNAMIC %s
+
+// CHECK-DYNAMIC: error: section: .dynamic is not contiguous with other relro sections
+
         .section .text, "ax", @progbits
         .global _start
         .global bar
         .global foo
 _start:
         .quad bar
         .quad foo
 
+        .section .empty, "ax", @progbits
+        .global empty
+empty: