[lld][ELF][test] Add testing for IE/LD TLS weak undef references

[jhenderson]

Summary

Whilst migrating/retiring some downstream testing, I came across a test for weak undef IE and LD TLS references, but was unable to find any equivalent in LLD's upstream testing. There does seem to be some slight subtle differences that could be worth testing compared to LE TLS references, in particular that IE can be relaxed to LE in this case, hence this change.

[grimar]

lld/test/ELF/tls-weak-undef.s

14

Where %t.o comes from? Doesn't seem the test creates it currently?

[jhenderson]

Fix reference to stale object and missing check-prefix. Not sure how I didn't spot the latter...

lld/test/ELF/tls-weak-undef.s

14

tls-le-weak-undef.s used %t.o as its input file and the object was still kicking around in my test output directory.

[grimar]

In D95124#2512145, @jhenderson wrote:

missing check-prefix. Not sure how I didn't spot the latter...

The CHECK line is still missing.

[jhenderson]

Reupload diff. Previous diff somehow was missing one of the changes.

[grimar]

LGTM with a nit, please wait for others.

lld/test/ELF/tls-weak-undef.s

13

I'd suggest to create an output in this case too. MIght be usefull for debugging.

[jhenderson]

Change to use separate output file to aid debugging.

[MaskRay]

LGTM.

lld/test/ELF/tls-weak-undef.s

13

A TLS undefined weak symbol

undefined is important.
TLS as a modifier is also useful.

25

Copy relocations are specific to executables. I think COPYRELOC may be misguiding.

[jhenderson]

I'll land this on Monday, as I'm coming to the end of my workday now.

lld/test/ELF/tls-weak-undef.s

13

I've gone with "An undefined weak TLS symbol" as I feel like it reads nicer.

25

COPYRELOC was the name in the pre-existing test my change is essentially updating. I'm not particularly familiar with this aspect of code. I'll go with ERROR since it's testing the error message, unless anybody else has got a better suggestion?

[jhenderson]

Address MaskRay's review comments.

lld/test/ELF/tls-le-weak-undef.s

-# REQUIRES: x86
-# RUN: llvm-mc -filetype=obj -triple=x86_64 %s -o %t.o
-# RUN: echo '.tbss; .globl tls; tls:' | llvm-mc -filetype=obj -triple=x86_64 - -o %tdef.o
-# RUN: ld.lld %t.o -o - | llvm-objdump -d - | FileCheck %s
-
-## A weak symbol does not fetch a lazy definition.
-# RUN: ld.lld %t.o --start-lib %tdef.o --end-lib -o - | llvm-objdump -d - | FileCheck %s
-
-## Undefined TLS symbols arbitrarily resolve to 0.
-# CHECK:  leaq 16(%rax), %rdx
-
-# RUN: ld.lld -shared %tdef.o -o %tdef.so
-# RUN: not ld.lld %t.o %tdef.so -o /dev/null 2>&1 | FileCheck --check-prefix=COPYRELOC %s
-
-# COPYRELOC: symbol 'tls' has no type
-
-.weak tls
-leaq tls@tpoff+16(%rax), %rdx

lld/test/ELF/tls-weak-undef.s

+# REQUIRES: x86
+
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/exec.s -o %texec.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/shared.s -o %tshared.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/ledef.s -o %tdef.o
+# RUN: ld.lld %texec.o -o %t.exec
+# RUN: ld.lld %tshared.o -o %t.shared --shared
+# RUN: llvm-objdump -d %t.exec | FileCheck %s --check-prefix=EXEC
+# RUN: llvm-objdump -d %t.shared | FileCheck %s --check-prefix=SHARED
+
+## A weak symbol does not fetch a lazy definition.
+# RUN: ld.lld %texec.o --start-lib %tdef.o --end-lib -o - | llvm-objdump -d - | FileCheck %s --check-prefix=EXEC
+
+## Undefined TLS symbols arbitrarily resolve to 0.
+# EXEC:   leaq 16(%rax), %rdx
+## Initial-exec references to undefined weak symbols can be relaxed to LE
+## references.
+# EXEC:   leaq 32(%rax), %rax
+# SHARED: leaq 48(%rax), %rcx
+
+# RUN: ld.lld -shared %tdef.o -o %tdef.so
+# RUN: not ld.lld %texec.o %tdef.so -o /dev/null 2>&1 | FileCheck --check-prefix=COPYRELOC %s
+
+# COPYRELOC: symbol 'le' has no type
+
+#--- ledef.s
+.tbss
+.globl le
+le:
+
+#--- exec.s
+.weak le
+leaq le@tpoff+16(%rax), %rdx
+
+.weak ie
+addq ie@gottpoff+32(%rip), %rax
+
+#--- shared.s
+.weak ld
+leaq ld@dtpoff+48(%rax), %rcx