[lld] r345977 - Change the timestamp of llvmcache-foo file to meet the thinLTO prune policy

[Teresa Johnson via llvm-commits]

Author: tejohnson
Date: Fri Nov  2 07:52:10 2018
New Revision: 345977

URL: http://llvm.org/viewvc/llvm-project?rev=345977&view=rev
Log:
Change  the timestamp of llvmcache-foo file to meet the thinLTO prune policy

Summary:

The case may randomly fail if we test it with command "
 while llvm-lit tools/lld/test/ELF/lto/cache.ll; do true; done". It is because the llvmcache-foo file is younger than llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6. But due to timestamp precision reason their timestamp is the same. Given the same timestamp, the file prune policy is to remove bigger size file first, so mostly foo file is removed for its bigger size. And the files size is under threshold after deleting foo file. That's what test case expect.

However sometimes, the precision is enough to measure that timestamp of llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are smaller than foo, so llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are deleted first. Since the files size is still above the file size threshold after deleting the 2 files, the foo file is also deleted. And then the test case fails, because it expect only one file should be deleted instead of 3.

The fix is to change the timestamp of llvmcache-foo file to meet the thinLTO prune policy.
The same fix is applied to llvm code at https://reviews.llvm.org/D52452.

Patch by Luo Yuanke.

Reviewers: ruiu, craig.topper, smaslov, Jianping, espindola, LuoYuanke

Subscribers: rupprecht, bjope, emaste, inglorion, arichardson, steven_wu, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D53123

Modified:
    lld/trunk/test/ELF/lto/cache.ll
    lld/trunk/test/wasm/lto/cache.ll

Modified: lld/trunk/test/ELF/lto/cache.ll
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/lto/cache.ll?rev=345977&r1=345976&r2=345977&view=diff
==============================================================================
--- lld/trunk/test/ELF/lto/cache.ll (original)
+++ lld/trunk/test/ELF/lto/cache.ll Fri Nov  2 07:52:10 2018
@@ -19,6 +19,10 @@
 ; RUN: ld.lld --thinlto-cache-dir=%t.cache --thinlto-cache-policy cache_size_bytes=128k:prune_interval=0s -o %t3 %t2.o %t.o
 ; RUN: ls %t.cache | count 5
 
+; Increase the age of llvmcache-foo, which will give it the oldest time stamp
+; so that it is processed and removed first.
+; RUN: touch -r %t.cache/llvmcache-foo -d '-2 minutes' %t.cache/llvmcache-foo
+
 ; This should remove it.
 ; RUN: ld.lld --thinlto-cache-dir=%t.cache --thinlto-cache-policy cache_size_bytes=32k:prune_interval=0s -o %t3 %t2.o %t.o
 ; RUN: ls %t.cache | count 4

Modified: lld/trunk/test/wasm/lto/cache.ll
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/wasm/lto/cache.ll?rev=345977&r1=345976&r2=345977&view=diff
==============================================================================
--- lld/trunk/test/wasm/lto/cache.ll (original)
+++ lld/trunk/test/wasm/lto/cache.ll Fri Nov  2 07:52:10 2018
@@ -17,6 +17,10 @@
 ; RUN: wasm-ld --thinlto-cache-dir=%t.cache --thinlto-cache-policy cache_size_bytes=128k:prune_interval=0s -o %t.wasm %t2.o %t.o
 ; RUN: ls %t.cache | count 5
 
+; Increase the age of llvmcache-foo, which will give it the oldest time stamp
+; so that it is processed and removed first.
+; RUN: touch -r %t.cache/llvmcache-foo -d '-2 minutes' %t.cache/llvmcache-foo
+
 ; This should remove it.
 ; RUN: wasm-ld --thinlto-cache-dir=%t.cache --thinlto-cache-policy cache_size_bytes=32k:prune_interval=0s -o %t.wasm %t2.o %t.o
 ; RUN: ls %t.cache | count 4