[lld] [lld][COFF][LTO] Implement /lldemit:llvm option (PR #66964)
Matheus Izvekov via llvm-commits
llvm-commits at lists.llvm.org
Mon Oct 2 09:22:40 PDT 2023
https://github.com/mizvekov updated https://github.com/llvm/llvm-project/pull/66964
>From 7e5bb36d2e847f79de21404872c64f062c4ce8df Mon Sep 17 00:00:00 2001
From: Matheus Izvekov <mizvekov at gmail.com>
Date: Thu, 21 Sep 2023 02:12:32 +0200
Subject: [PATCH] [lld][COFF][LTO] Implement /lldemit:llvm option
With this new option, bitcode will be emited instead of object code.
This is analogous to the `--plugin-opt=emit-llvm` option in the ELF
linker.
---
lld/COFF/Config.h | 3 +++
lld/COFF/Driver.cpp | 14 +++++++++++++-
lld/COFF/LTO.cpp | 9 +++++++++
lld/COFF/Options.td | 1 +
lld/test/COFF/lto-emit-llvm.ll | 14 ++++++++++++++
5 files changed, 40 insertions(+), 1 deletion(-)
create mode 100644 lld/test/COFF/lto-emit-llvm.ll
diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
index 4ade2c953c73e40..e66ab3a32c56721 100644
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -48,6 +48,8 @@ enum class ExportSource {
ModuleDefinition,
};
+enum class EmitKind { Obj, LLVM };
+
// Represents an /export option.
struct Export {
StringRef name; // N in /export:N or /export:E=N
@@ -311,6 +313,7 @@ struct Configuration {
bool pseudoRelocs = false;
bool stdcallFixup = false;
bool writeCheckSum = false;
+ EmitKind emit = EmitKind::Obj;
};
} // namespace lld::coff
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index e2f414f78ecb7bc..75ac6d965eba626 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1852,6 +1852,17 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
if (args.hasArg(OPT_lldsavetemps))
config->saveTemps = true;
+ // Handle /lldemit
+ if (auto *arg = args.getLastArg(OPT_lldemit)) {
+ StringRef s = arg->getValue();
+ if (s == "obj")
+ config->emit = EmitKind::Obj;
+ else if (s == "llvm")
+ config->emit = EmitKind::LLVM;
+ else
+ error("/lldemit: unknown option: " + s);
+ }
+
// Handle /kill-at
if (args.hasArg(OPT_kill_at))
config->killAt = true;
@@ -2395,7 +2406,8 @@ void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
// If -thinlto-index-only is given, we should create only "index
// files" and not object files. Index file creation is already done
// in addCombinedLTOObject, so we are done if that's the case.
- if (config->thinLTOIndexOnly)
+ // Likewise, don't emit object files for other /lldemit options.
+ if (config->emit != EmitKind::Obj || config->thinLTOIndexOnly)
return;
// If we generated native object files from bitcode files, this resolves
diff --git a/lld/COFF/LTO.cpp b/lld/COFF/LTO.cpp
index 6ca000b466a1264..6e835d055479c82 100644
--- a/lld/COFF/LTO.cpp
+++ b/lld/COFF/LTO.cpp
@@ -87,6 +87,15 @@ lto::Config BitcodeCompiler::createConfig() {
c.RunCSIRInstr = ctx.config.ltoCSProfileGenerate;
c.PGOWarnMismatch = ctx.config.ltoPGOWarnMismatch;
+ if (ctx.config.emit == EmitKind::LLVM) {
+ c.PostInternalizeModuleHook = [this](size_t task, const Module &m) {
+ if (std::unique_ptr<raw_fd_ostream> os =
+ openLTOOutputFile(ctx.config.outputFile))
+ WriteBitcodeToFile(m, *os, false);
+ return false;
+ };
+ }
+
if (ctx.config.saveTemps)
checkError(c.addSaveTemps(std::string(ctx.config.outputFile) + ".",
/*UseInputModulePath*/ true));
diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
index ea4ddb2d849534e..22add8ff72b95d3 100644
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -232,6 +232,7 @@ defm demangle : B<"demangle",
def include_optional : Joined<["/", "-", "/?", "-?"], "includeoptional:">,
HelpText<"Add symbol as undefined, but allow it to remain undefined">;
def kill_at : F<"kill-at">;
+def lldemit : P<"lldemit", "Specify output type">;
def lldmingw : F<"lldmingw">;
def noseh : F<"noseh">;
def osversion : P_priv<"osversion">;
diff --git a/lld/test/COFF/lto-emit-llvm.ll b/lld/test/COFF/lto-emit-llvm.ll
new file mode 100644
index 000000000000000..985058de10a4888
--- /dev/null
+++ b/lld/test/COFF/lto-emit-llvm.ll
@@ -0,0 +1,14 @@
+; REQUIRES: x86
+; RUN: llvm-as -o %T/lto.obj %s
+
+; RUN: lld-link /lldemit:llvm /out:%T/lto.bc /entry:main /subsystem:console %T/lto.obj
+; RUN: llvm-dis %T/lto.bc -o - | FileCheck %s
+
+; CHECK: define void @main()
+
+target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+define void @main() {
+ ret void
+}
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