[PATCH] D112124: [ThinLTO] Append original object file name to ThinLTO generated object file's name, so that it can be recorded in link map file.
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Tue Oct 19 23:03:58 PDT 2021
xushuangqing created this revision.
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Herald added subscribers: ormris, pengfei, hiraditya, inglorion.
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Problem
=======
When I use ThinLTO, ThinLTOCodeGenerator will generate object file whose filename looks like this:
0.x86_64.thinlto.o
1.x86_64.thinlto.o
2.x86_64.thinlto.o
3.x86_64.thinlto.o
So when I use `-map` option during linking, the generated link map file will contain these object files. It looks like:
# Path: ...
# Arch: x86_64
# Object files:
[ 0] linker synthesized
...
[ 10] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/0.x86_64.thinlto.o
[ 11] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/1.x86_64.thinlto.o
[ 12] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/2.x86_64.thinlto.o
[ 13] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/3.x86_64.thinlto.o
[ 14] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/4.x86_64.thinlto.o
# Sections:
# Address Size Segment Section
...
# Symbols:
# Address Size File Name
...
# Dead Stripped Symbols:
# Size File Name
...
If I want to figure out each source file's size in the binary file, the `0.x86_64.thinlto.o` confuses me. It contains few information about the original source file.
Optimize
========
As filenames like `0.x86_64.thinlto.o` are joint in ThinLTOCodeGenerator::writeGeneratedObject, we can append the original object file name to it.
So the file name would looks like:
[ 10] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/0.x86_64.ViewController.o0.thinlto.o
[ 11] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/1.x86_64.AppDelegate.o1.thinlto.o
[ 12] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/2.x86_64.main.o2.thinlto.o
[ 13] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/3.x86_64.SceneDelegate.o3.thinlto.o
[ 14] /Users/xushuangqing/Library/Developer/Xcode/DerivedData/XSQLTODemo-flxqbdftarzrkoeyxgvupfvnvbue/Build/Intermediates.noindex/XSQLTODemo.build/Release-iphonesimulator/XSQLTODemo.build/Objects-normal/x86_64/XSQLTODemo_lto.o/4.x86_64.libXSQStaticLib.a(XSQObject.o)4.thinlto.o
When we analyze the link map, we can figure out each source file's size in the binary file.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D112124
Files:
llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
llvm/lib/LTO/ThinLTOCodeGenerator.cpp
Index: llvm/lib/LTO/ThinLTOCodeGenerator.cpp
===================================================================
--- llvm/lib/LTO/ThinLTOCodeGenerator.cpp
+++ llvm/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -964,11 +964,16 @@
/// Returns the path to the generated file in SavedObjectsDirectoryPath.
std::string
ThinLTOCodeGenerator::writeGeneratedObject(int count, StringRef CacheEntryPath,
- const MemoryBuffer &OutputBuffer) {
+ const MemoryBuffer &OutputBuffer,
+ StringRef objectFileName) {
auto ArchName = TMBuilder.TheTriple.getArchName();
SmallString<128> OutputPath(SavedObjectsDirectoryPath);
- llvm::sys::path::append(OutputPath,
- Twine(count) + "." + ArchName + ".thinlto.o");
+ if (objectFileName.empty())
+ llvm::sys::path::append(OutputPath,
+ Twine(count) + "." + ArchName + ".thinlto.o");
+ else
+ llvm::sys::path::append(OutputPath, Twine(count) + "." + ArchName + "." +
+ objectFileName + ".thinlto.o");
OutputPath.c_str(); // Ensure the string is null terminated.
if (sys::fs::exists(OutputPath))
sys::fs::remove(OutputPath);
@@ -1164,6 +1169,10 @@
auto &Mod = Modules[IndexCount];
Pool.async([&](int count) {
auto ModuleIdentifier = Mod->getName();
+
+ StringRef moduleIdentifierFileName =
+ llvm::sys::path::filename(ModuleIdentifier);
+
auto &ExportList = ExportLists[ModuleIdentifier];
auto &DefinedGVSummaries = ModuleToDefinedGVSummaries[ModuleIdentifier];
@@ -1188,7 +1197,8 @@
ProducedBinaries[count] = std::move(ErrOrBuffer.get());
else
ProducedBinaryFiles[count] = writeGeneratedObject(
- count, CacheEntryPath, *ErrOrBuffer.get());
+ count, CacheEntryPath, *ErrOrBuffer.get(),
+ moduleIdentifierFileName);
return;
}
}
@@ -1246,7 +1256,7 @@
return;
}
ProducedBinaryFiles[count] = writeGeneratedObject(
- count, CacheEntryPath, *OutputBuffer);
+ count, CacheEntryPath, *OutputBuffer, moduleIdentifierFileName);
}, IndexCount);
}
}
Index: llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
===================================================================
--- llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
+++ llvm/include/llvm/LTO/legacy/ThinLTOCodeGenerator.h
@@ -299,7 +299,8 @@
* SavedObjectsDirectoryPath.
*/
std::string writeGeneratedObject(int count, StringRef CacheEntryPath,
- const MemoryBuffer &OutputBuffer);
+ const MemoryBuffer &OutputBuffer,
+ StringRef objectFileName = "");
/**@}*/
private:
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