[llvm] 61fc10d - [ThinLTO] add post-thinlto-merge option to -lto-embed-bitcode
Mircea Trofin via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 15 15:56:21 PDT 2020
Author: Mircea Trofin
Date: 2020-09-15T15:56:11-07:00
New Revision: 61fc10d6a520f267e11009ce8fce88d73615796b
URL: https://github.com/llvm/llvm-project/commit/61fc10d6a520f267e11009ce8fce88d73615796b
DIFF: https://github.com/llvm/llvm-project/commit/61fc10d6a520f267e11009ce8fce88d73615796b.diff
LOG: [ThinLTO] add post-thinlto-merge option to -lto-embed-bitcode
This will embed bitcode after (Thin)LTO merge, but before optimizations.
In the case the thinlto backend is called from clang, the .llvmcmd
section is also produced. Doing so in the case where the caller is the
linker doesn't yet have a motivation, and would require plumbing through
command line args.
Differential Revision: https://reviews.llvm.org/D87636
Added:
clang/test/CodeGen/Inputs/start-lib1.ll
clang/test/CodeGen/Inputs/start-lib2.ll
clang/test/CodeGen/thinlto_embed_bitcode.ll
Modified:
clang/lib/CodeGen/BackendUtil.cpp
llvm/include/llvm/LTO/LTOBackend.h
llvm/lib/LTO/LTOBackend.cpp
llvm/test/LTO/X86/Inputs/start-lib1.ll
llvm/test/LTO/X86/embed-bitcode.ll
Removed:
################################################################################
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 5fc80d4fae71..01f7e239f790 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -1647,9 +1647,10 @@ static void runThinLTOBackend(
Conf.CGFileType = getCodeGenFileType(Action);
break;
}
- if (Error E = thinBackend(
- Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
- ModuleToDefinedGVSummaries[M->getModuleIdentifier()], ModuleMap)) {
+ if (Error E =
+ thinBackend(Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
+ ModuleToDefinedGVSummaries[M->getModuleIdentifier()],
+ ModuleMap, &CGOpts.CmdArgs)) {
handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
errs() << "Error running ThinLTO backend: " << EIB.message() << '\n';
});
diff --git a/clang/test/CodeGen/Inputs/start-lib1.ll b/clang/test/CodeGen/Inputs/start-lib1.ll
new file mode 100644
index 000000000000..18b6ea25386f
--- /dev/null
+++ b/clang/test/CodeGen/Inputs/start-lib1.ll
@@ -0,0 +1,9 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @bar()
+
+define void @foo() {
+ call void @bar()
+ ret void
+}
diff --git a/clang/test/CodeGen/Inputs/start-lib2.ll b/clang/test/CodeGen/Inputs/start-lib2.ll
new file mode 100644
index 000000000000..68b3c8362808
--- /dev/null
+++ b/clang/test/CodeGen/Inputs/start-lib2.ll
@@ -0,0 +1,6 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @bar() {
+ ret void
+}
diff --git a/clang/test/CodeGen/thinlto_embed_bitcode.ll b/clang/test/CodeGen/thinlto_embed_bitcode.ll
new file mode 100644
index 000000000000..4efb525e5f3e
--- /dev/null
+++ b/clang/test/CodeGen/thinlto_embed_bitcode.ll
@@ -0,0 +1,30 @@
+; REQUIRES: x86-registered-target
+
+; check the -lto-embed-bitcode=post-thinlto-merge does not perform optimizations
+; we expect 't1' - i.e start-lib1.ll's products - have both foo and bar defined,
+; but the bar call is still made from foo.
+; RUN: opt -module-summary %p/Inputs/start-lib1.ll -o %t1.bc
+; RUN: opt -module-summary %p/Inputs/start-lib2.ll -o %t2.bc
+; RUN: llvm-lto -thinlto -o %t.o %t1.bc %t2.bc
+
+; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t.o -x ir %t1.bc -c -fthinlto-index=%t.o.thinlto.bc -mllvm -lto-embed-bitcode=post-merge-pre-opt
+; RUN: llvm-readelf -S %t.o | FileCheck %s --check-prefixes=CHECK-ELF,CHECK-CMD
+; RUN: llvm-objcopy --dump-section=.llvmbc=%t-embedded.bc %t.o /dev/null
+; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefixes=CHECK,CHECK-NOOPT
+
+; For the optimized case, we expect the inlining of foo into bar to happen.
+; RUN: %clang -target x86_64-unknown-linux-gnu -O2 -o %t.o -x ir %t1.bc -c -fthinlto-index=%t.o.thinlto.bc -mllvm -lto-embed-bitcode=optimized
+; RUN: llvm-readelf -S %t.o | FileCheck %s --check-prefixes=CHECK-ELF,CHECK-NO-CMD
+; RUN: llvm-objcopy --dump-section=.llvmbc=%t-embedded.bc %t.o /dev/null
+; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefixes=CHECK,CHECK-OPT
+
+; CHECK-ELF: .text PROGBITS 0000000000000000 [[#%x,OFF:]] [[#%x,SIZE:]] 00 AX 0
+; CHECK-ELF-NEXT: .llvmbc PROGBITS 0000000000000000 [[#%x,OFF:]] [[#%x,SIZE:]] 00 0
+; CHECK-ELF-CMD: .llvmcmd
+; CHECK-ELF-NO-CMD-NOT: .llvmcmd
+
+; CHECK: define void @foo()
+; CHECK-OPT-NEXT: ret void
+; CHECK-NOOPT-NEXT: call void @bar()
+; CHECK-NOOPT: define available_externally void @bar() !thinlto_src_module !0 {
+; CHECK-NOOPT-NEXT: ret void
diff --git a/llvm/include/llvm/LTO/LTOBackend.h b/llvm/include/llvm/LTO/LTOBackend.h
index 0226e4a3fbf5..735969c47039 100644
--- a/llvm/include/llvm/LTO/LTOBackend.h
+++ b/llvm/include/llvm/LTO/LTOBackend.h
@@ -44,7 +44,8 @@ Error thinBackend(const Config &C, unsigned Task, AddStreamFn AddStream,
Module &M, const ModuleSummaryIndex &CombinedIndex,
const FunctionImporter::ImportMapTy &ImportList,
const GVSummaryMapTy &DefinedGlobals,
- MapVector<StringRef, BitcodeModule> &ModuleMap);
+ MapVector<StringRef, BitcodeModule> &ModuleMap,
+ const std::vector<uint8_t> *CmdArgs = nullptr);
Error finalizeOptimizationRemarks(
std::unique_ptr<ToolOutputFile> DiagOutputFile);
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 00309b6d712f..4c5778e81184 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -50,9 +50,12 @@
using namespace llvm;
using namespace lto;
+#define DEBUG_TYPE "lto-backend"
+
enum class LTOBitcodeEmbedding {
DoNotEmbed = 0,
EmbedOptimized = 1,
+ EmbedPostMergePreOptimized = 2
};
static cl::opt<LTOBitcodeEmbedding> EmbedBitcode(
@@ -60,7 +63,10 @@ static cl::opt<LTOBitcodeEmbedding> EmbedBitcode(
cl::values(clEnumValN(LTOBitcodeEmbedding::DoNotEmbed, "none",
"Do not embed"),
clEnumValN(LTOBitcodeEmbedding::EmbedOptimized, "optimized",
- "Embed after all optimization passes")),
+ "Embed after all optimization passes"),
+ clEnumValN(LTOBitcodeEmbedding::EmbedPostMergePreOptimized,
+ "post-merge-pre-opt",
+ "Embed post merge, but before optimizations")),
cl::desc("Embed LLVM bitcode in object files produced by LTO"));
LLVM_ATTRIBUTE_NORETURN static void reportOpenError(StringRef Path, Twine Msg) {
@@ -346,7 +352,25 @@ static void runOldPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
bool opt(const Config &Conf, TargetMachine *TM, unsigned Task, Module &Mod,
bool IsThinLTO, ModuleSummaryIndex *ExportSummary,
- const ModuleSummaryIndex *ImportSummary) {
+ const ModuleSummaryIndex *ImportSummary,
+ const std::vector<uint8_t> *CmdArgs = nullptr) {
+ if (EmbedBitcode == LTOBitcodeEmbedding::EmbedPostMergePreOptimized) {
+ // FIXME: the motivation for capturing post-merge bitcode and command line
+ // is replicating the compilation environment from bitcode, without needing
+ // to understand the dependencies (the functions to be imported). This
+ // assumes a clang - based invocation, case in which we have the command
+ // line.
+ // It's not very clear how the above motivation would map in the
+ // linker-based case, so we currently don't plumb the command line args in
+ // that case.
+ if (CmdArgs == nullptr)
+ LLVM_DEBUG(
+ dbgs() << "Post-(Thin)LTO merge bitcode embedding was requested, but "
+ "command line arguments are not available");
+ llvm::EmbedBitcodeInModule(Mod, llvm::MemoryBufferRef(),
+ /*EmbedBitcode*/ true,
+ /*EmbedMarker*/ false, CmdArgs);
+ }
// FIXME: Plumb the combined index into the new pass manager.
if (!Conf.OptPipeline.empty())
runNewPMCustomPasses(Conf, Mod, TM, Conf.OptPipeline, Conf.AAPipeline,
@@ -531,7 +555,8 @@ Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream,
Module &Mod, const ModuleSummaryIndex &CombinedIndex,
const FunctionImporter::ImportMapTy &ImportList,
const GVSummaryMapTy &DefinedGlobals,
- MapVector<StringRef, BitcodeModule> &ModuleMap) {
+ MapVector<StringRef, BitcodeModule> &ModuleMap,
+ const std::vector<uint8_t> *CmdArgs) {
Expected<const Target *> TOrErr = initAndLookupTarget(Conf, Mod);
if (!TOrErr)
return TOrErr.takeError();
@@ -599,7 +624,8 @@ Error lto::thinBackend(const Config &Conf, unsigned Task, AddStreamFn AddStream,
return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
if (!opt(Conf, TM.get(), Task, Mod, /*IsThinLTO=*/true,
- /*ExportSummary=*/nullptr, /*ImportSummary=*/&CombinedIndex))
+ /*ExportSummary=*/nullptr, /*ImportSummary=*/&CombinedIndex,
+ CmdArgs))
return finalizeOptimizationRemarks(std::move(DiagnosticOutputFile));
codegen(Conf, TM.get(), AddStream, Task, Mod, CombinedIndex);
diff --git a/llvm/test/LTO/X86/Inputs/start-lib1.ll b/llvm/test/LTO/X86/Inputs/start-lib1.ll
index 9f42e6afff0f..18b6ea25386f 100644
--- a/llvm/test/LTO/X86/Inputs/start-lib1.ll
+++ b/llvm/test/LTO/X86/Inputs/start-lib1.ll
@@ -4,5 +4,6 @@ target triple = "x86_64-unknown-linux-gnu"
declare void @bar()
define void @foo() {
+ call void @bar()
ret void
}
diff --git a/llvm/test/LTO/X86/embed-bitcode.ll b/llvm/test/LTO/X86/embed-bitcode.ll
index c8b4d0faa747..bdddd079d226 100644
--- a/llvm/test/LTO/X86/embed-bitcode.ll
+++ b/llvm/test/LTO/X86/embed-bitcode.ll
@@ -11,13 +11,20 @@
; RUN: llvm-lto2 run -r %t1.o,_start,px -r %t2.o,foo,px -r %t3.o,bar,px -r %t2.o,bar,lx -lto-embed-bitcode=optimized -o %t3 %t1.o %t2.o %t3.o
; RUN: llvm-readelf -S %t3.0 | FileCheck %s --check-prefix=CHECK-ELF
; RUN: llvm-objcopy --dump-section=.llvmbc=%t-embedded.bc %t3.0 /dev/null
-; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefix=CHECK-LL
+; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefixes=CHECK-LL,CHECK-OPT
+
+; RUN: llvm-lto2 run -r %t1.o,_start,px -r %t2.o,foo,px -r %t3.o,bar,px -r %t2.o,bar,lx -lto-embed-bitcode=post-merge-pre-opt -o %t3 %t1.o %t2.o %t3.o
+; RUN: llvm-readelf -S %t3.0 | FileCheck %s --check-prefix=CHECK-ELF
+; RUN: llvm-objcopy --dump-section=.llvmbc=%t-embedded.bc %t3.0 /dev/null
+; RUN: llvm-dis %t-embedded.bc -o - | FileCheck %s --check-prefixes=CHECK-LL,CHECK-NOOPT
; CHECK-ELF: .text PROGBITS 0000000000000000 [[#%x,OFF:]] [[#%x,SIZE:]] 00 AX 0
; CHECK-ELF-NEXT: .llvmbc PROGBITS 0000000000000000 [[#%x,OFF:]] [[#%x,SIZE:]] 00 0
; CHECK-LL: @_start
; CHECK-LL: @foo
+; CHECK-OPT-NEXT: ret void
+; CHECK-NOOPT-NEXT: call void @bar
; CHECK-LL: @bar
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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