[lld/test/ELF] Test fetch from archive to resolve undefined symbols in shared libs

[pirama]

Summary

Add missing test coverage uncovered in review of D108006.

[MaskRay]

lld/test/ELF/undef-in-shared-from-lazy.s

2

# REQUIRES: x86
## Regular comments.
# RUN:
# CHECK: ...

3

Consider rm -fr %t && split-file %s %t

4

21

Use _start instead of main, then you can omit --entry

[MaskRay]

Worth checking whether archive-fetch.s can be folded into the test.

[pirama]

Update with review comments.

[pirama]

In D108328#2957896, @MaskRay wrote:

Worth checking whether archive-fetch.s can be folded into the test.

The test was added independent of the code change. Can you point me to the relevant code in InputFiles.cpp? Is it https://github.com/llvm/llvm-project/blob/9b9e7f6f4e05baa99a795e0cce60ba86091acc9a/lld/ELF/InputFiles.cpp#L1804?

[MaskRay]

Looks like archive-fetch.s is unrelated. LG.

I do encourage that contributors try making tests a bit more orthogonal and reorganize tests whenever that makes sense.

undef-in-shared-from-lazy.s => how about dso-undef-extract-lazy?

lld/test/ELF/undef-in-shared-from-lazy.s

36

Use .s suffix

40

Use .s suffix

[pirama]

• rename file
• append '.s' to split-file output names

[pirama]

lld/test/ELF/undef-in-shared-from-lazy.s

36

Added for main above as well.

lld/test/ELF/undef-in-shared-from-lazy.s

+// REQUIRES: x86
+// Build %t1.o with a trivial main function
+// RUN: echo -e ".text\n.globl main\n.type main,@function\nmain:\nret" > %t1.s
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %t1.s -o %t1.o
+
+// Build %t2.a which defines a global 'foo'
+// RUN: echo -e ".global foo\nfoo:" > %t2.s
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %t2.s -o %t2.o
+// RUN: rm -f %t2.a
+// RUN: llvm-ar rc %t2.a %t2.o
+
+// Build %t3.so that has a reference to 'foo'
+// RUN: echo ".global foo" > %t3.s
+// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %t3.s -o %t3.o
+// RUN: ld.lld %t3.o -o %t3.so -shared
+
+// Test that 'foo' from %t2.a is fetched to define 'foo' needed by %t3.so.
+// Test both cases where the archive is before or after the shared library in
+// link order.
+
+// RUN: ld.lld --entry=main %t1.o %t2.a %t3.so -o %t
+// RUN: llvm-readelf --dyn-symbols %t | FileCheck %s --check-prefix=CHECK-FETCH
+
+// RUN: ld.lld --entry=main %t1.o %t3.so %t2.a -o %t
+// RUN: llvm-readelf --dyn-symbols %t | FileCheck %s --check-prefix=CHECK-FETCH
+
+// CHECK-FETCH: GLOBAL DEFAULT {{[0-9]+}} foo