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[lld-macho] Ensure cached objects are affected by `-object_path_lto` 

This refactors LTO compile to look more like COFF, where cache hits and misses are all funneled through the same code path.

Previously, cache hits were *not* being saved to -object_path_lto, which led to them sometimes falling out of the cache before dsymutil could process them. As a side effect of the refactor, cached objects are now saved with -save-temps as well, which seems desirable.

(Deleted lld/test/MachO/lto-cache-dsymutil.ll and rolled it into lld/test/MachO/lto-object-path.ll, since the cache-only, non object path approach is unreliable anyway).

Differential Revision: https://reviews.llvm.org/D131624
This commit is contained in:
Leonard Grey 2022-08-10 17:44:27 -04:00
parent fba88adc89
commit 6c62795058
3 changed files with 28 additions and 44 deletions
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33
lld/MachO/LTO.cpp
View File

@ -131,13 +131,6 @@ std::vector<ObjFile *> BitcodeCompiler::compile() {
if (!config->thinLTOCacheDir.empty())
pruneCache(config->thinLTOCacheDir, config->thinLTOCachePolicy);
if (config->saveTemps) {
if (!buf[0].empty())
saveBuffer(buf[0], config->outputFile + ".lto.o");
for (unsigned i = 1; i != maxTasks; ++i)
saveBuffer(buf[i], config->outputFile + Twine(i) + ".lto.o");
}
// In ThinLTO mode, Clang passes a temporary directory in -object_path_lto,
// while the argument is a single file in FullLTO mode.
bool objPathIsDir = true;
@ -156,9 +149,23 @@ std::vector<ObjFile *> BitcodeCompiler::compile() {
}
std::vector<ObjFile *> ret;
for (unsigned i = 0; i != maxTasks; ++i) {
if (buf[i].empty())
for (unsigned i = 0; i < maxTasks; ++i) {
// Get the native object contents either from the cache or from memory. Do
// not use the cached MemoryBuffer directly to ensure dsymutil does not
// race with the cache pruner.
StringRef objBuf;
if (files[i])
objBuf = files[i]->getBuffer();
else
objBuf = buf[i];
if (objBuf.empty())
continue;
// FIXME: should `saveTemps` and `ltoObjPath` use the same file name?
if (config->saveTemps)
saveBuffer(objBuf,
config->outputFile + ((i == 0) ? "" : Twine(i)) + ".lto.o");
SmallString<261> filePath("/tmp/lto.tmp");
uint32_t modTime = 0;
if (!config->ltoObjPath.empty()) {
@ -167,14 +174,12 @@ std::vector<ObjFile *> BitcodeCompiler::compile() {
path::append(filePath, Twine(i) + "." +
getArchitectureName(config->arch()) +
".lto.o");
saveBuffer(buf[i], filePath);
saveBuffer(objBuf, filePath);
modTime = getModTime(filePath);
}
ret.push_back(make<ObjFile>(
MemoryBufferRef(buf[i], saver().save(filePath.str())), modTime, ""));
MemoryBufferRef(objBuf, saver().save(filePath.str())), modTime, ""));
}
for (std::unique_ptr<MemoryBuffer> &file : files)
if (file)
ret.push_back(make<ObjFile>(*file, 0, ""));
return ret;
}

28
lld/test/MachO/lto-cache-dsymutil.ll
View File

@ -1,28 +0,0 @@
; REQUIRES: x86
; RUN: rm -rf %t; mkdir %t
; RUN: opt -module-hash -module-summary %s -o %t/foo.o
; RUN: %lld -cache_path_lto %t/cache -o %t/test %t/foo.o
;; Check that dsymutil is able to read the .o file out of the thinlto cache.
; RUN: dsymutil -f -o - %t/test | llvm-dwarfdump - | FileCheck %s
; CHECK: DW_AT_name ("test.cpp")
target triple = "x86_64-apple-macosx10.15.0"
target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
define void @main() #0 !dbg !4 {
ret void
}
!llvm.module.flags = !{ !0, !1 }
!llvm.dbg.cu = !{!2}
!0 = !{i32 7, !"Dwarf Version", i32 4}
!1 = !{i32 2, !"Debug Info Version", i32 3}
!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, emissionKind: FullDebug)
!3 = !DIFile(filename: "test.cpp", directory: "/tmp")
!4 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 1, type: !5, scopeLine: 1, unit: !2)
!5 = !DISubroutineType(types: !6)
!6 = !{}

11
lld/test/MachO/lto-object-path.ll
View File

@ -2,7 +2,7 @@
; UNSUPPORTED: system-windows
; RUN: rm -rf %t; mkdir %t
; RUN: llvm-as %s -o %t/test.o
; RUN: opt -thinlto-bc %s -o %t/test.o
; RUN: %lld %t/test.o -o %t/test
; RUN: llvm-nm -pa %t/test | FileCheck %s --check-prefixes CHECK,NOOBJPATH
@ -10,6 +10,12 @@
; RUN: %lld %t/test.o -o %t/test -object_path_lto %t/lto-temps
; RUN: llvm-nm -pa %t/test | FileCheck %s --check-prefixes CHECK,OBJPATH-DIR -DDIR=%t/lto-temps
;; Ensure object path is still used if the cache is used
; RUN: %lld %t/test.o -o %t/test -object_path_lto %t/lto-temps -prune_interval_lto 20 -cache_path_lto %t/cache --thinlto-cache-policy=cache_size_files=1:cache_size_bytes=10
; RUN: llvm-nm -pa %t/test | FileCheck %s --check-prefixes CHECK,OBJPATH-DIR -DDIR=%t/lto-temps
;; And that dsymutil can read the result
; RUN: dsymutil -f -o - %t/test | llvm-dwarfdump - | FileCheck %s --check-prefix=DSYM
;; check that the object path can be an existing file
; RUN: touch %t/lto-tmp.o
; RUN: %lld %t/test.o -o %t/test -object_path_lto %t/lto-tmp.o
@ -19,12 +25,13 @@
; CHECK: 0000000000000000 - 00 0000 SO /tmp/test.cpp
; NOOBJPATH-NEXT: 0000000000000000 - 03 0001 OSO /tmp/lto.tmp
;; check that modTime is nonzero when `-object_path_lto` is provided
; OBJPATH-DIR-NEXT: {{[0-9a-f]*[1-9a-f]+[0-9a-f]*}} - 03 0001 OSO [[DIR]]/0.x86_64.lto.o
; OBJPATH-DIR-NEXT: {{[0-9a-f]*[1-9a-f]+[0-9a-f]*}} - 03 0001 OSO [[DIR]]/1.x86_64.lto.o
; OBJPATH-FILE-NEXT: {{[0-9a-f]*[1-9a-f]+[0-9a-f]*}} - 03 0001 OSO [[FILE]]
; CHECK-NEXT: {{[0-9a-f]+}} - 01 0000 FUN _main
; CHECK-NEXT: 0000000000000001 - 00 0000 FUN
; CHECK-NEXT: 0000000000000000 - 01 0000 SO
; CHECK-NEXT: {{[0-9a-f]+}} T _main
; DSYM: DW_AT_name ("test.cpp")
target triple = "x86_64-apple-macosx10.15.0"
target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"