[PATCH] D154295: [Driver][MSVC] Support DWARF fission when using LTO on Windows
Haohai, Wen via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Sat Jul 1 21:10:02 PDT 2023
HaohaiWen created this revision.
Herald added subscribers: ormris, steven_wu, hiraditya, inglorion.
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Herald added a project: clang.
D154070 <https://reviews.llvm.org/D154070> has added /dwodir to lld/COFF to tells LTO backend to create dwo
directory and files. This patch makes clang to emit /dwodir to lld when
user specify -gsplit-dwarf with LTO. This behavior is simiar to DWARF
fission with LTO for ELF.
A simple use case:
$clang-cl -c -flto -gdwarf main.c -o main.o
$clang-cl -c -flto -gdwarf a.c -o a.o
$clang-cl -flto -fuse-ld=lld -gdwarf -gsplit-dwarf main.o a.o
This'll generate a dwo file: main.exe_dwo/0.dwo
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D154295
Files:
clang/lib/Driver/ToolChains/MSVC.cpp
clang/test/Driver/lto-dwo.c
Index: clang/test/Driver/lto-dwo.c
===================================================================
--- clang/test/Driver/lto-dwo.c
+++ clang/test/Driver/lto-dwo.c
@@ -1,6 +1,9 @@
// Confirm that -gsplit-dwarf=DIR is passed to linker
// RUN: %clang --target=x86_64-unknown-linux -### %s -flto=thin -gsplit-dwarf -o a.out 2> %t
-// RUN: FileCheck -check-prefix=CHECK-LINK-DWO-DIR-DEFAULT < %t %s
+// RUN: FileCheck -check-prefix=CHECK-LINK-ELF-DWO-DIR-DEFAULT < %t %s
+// RUN: %clang_cl --target=x86_64-unknown-windows-msvc -### -fuse-ld=lld -flto -gsplit-dwarf -o a.out -- %s 2> %t
+// RUN: FileCheck -check-prefix=CHECK-LINK-COFF-DWO-DIR-DEFAULT < %t %s
//
-// CHECK-LINK-DWO-DIR-DEFAULT: "-plugin-opt=dwo_dir=a.out_dwo"
+// CHECK-LINK-ELF-DWO-DIR-DEFAULT: "-plugin-opt=dwo_dir=a.out_dwo"
+// CHECK-LINK-COFF-DWO-DIR-DEFAULT: "/dwodir:a.out_dwo"
Index: clang/lib/Driver/ToolChains/MSVC.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MSVC.cpp
+++ clang/lib/Driver/ToolChains/MSVC.cpp
@@ -277,11 +277,18 @@
else if (Linker.equals_insensitive("lld"))
Linker = "lld-link";
- if (Linker == "lld-link")
+ if (Linker == "lld-link") {
for (Arg *A : Args.filtered(options::OPT_vfsoverlay))
CmdArgs.push_back(
Args.MakeArgString(std::string("/vfsoverlay:") + A->getValue()));
+ if (C.getDriver().isUsingLTO() &&
+ Args.hasFlag(options::OPT_gsplit_dwarf, options::OPT_gno_split_dwarf,
+ false))
+ CmdArgs.push_back(Args.MakeArgString(Twine("/dwodir:") +
+ Output.getFilename() + "_dwo"));
+ }
+
// Add filenames, libraries, and other linker inputs.
for (const auto &Input : Inputs) {
if (Input.isFilename()) {
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