Index: include/llvm/LTO/LTO.h
===================================================================
--- include/llvm/LTO/LTO.h
+++ include/llvm/LTO/LTO.h
@@ -85,6 +85,13 @@
namespace lto {
+/// Given the original \p Path to an output file, replace any path
+/// prefix matching \p OldPrefix with \p NewPrefix. Also, create the
+/// resulting directory if it does not yet exist.
+std::string getThinLTOOutputFile(const std::string &Path,
+ const std::string &OldPrefix,
+ const std::string &NewPrefix);
+
class LTO;
struct SymbolResolution;
class ThinBackendProc;
Index: lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- lib/Bitcode/Reader/BitcodeReader.cpp
+++ lib/Bitcode/Reader/BitcodeReader.cpp
@@ -6097,13 +6097,18 @@
return error("Invalid record");
break;
case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
- assert(VSTOffset > 0 && "Expected non-zero VST offset");
assert(!SeenValueSymbolTable &&
"Already read VST when parsing summary block?");
- if (std::error_code EC =
- parseValueSymbolTable(VSTOffset, ValueIdToLinkageMap))
- return EC;
- SeenValueSymbolTable = true;
+ // We might not have a VST if there were no values in the
+ // summary. An empty summary block generated when we are
+ // performing ThinLTO compiles so we don't later invoke
+ // the regular LTO process on them.
+ if (VSTOffset > 0) {
+ if (std::error_code EC =
+ parseValueSymbolTable(VSTOffset, ValueIdToLinkageMap))
+ return EC;
+ SeenValueSymbolTable = true;
+ }
SeenGlobalValSummary = true;
if (std::error_code EC = parseEntireSummary())
return EC;
Index: lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- lib/Bitcode/Writer/BitcodeWriter.cpp
+++ lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3341,13 +3341,15 @@
/// Emit the per-module summary section alongside the rest of
/// the module's bitcode.
void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
- if (Index->begin() == Index->end())
- return;
-
Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
+ if (Index->begin() == Index->end()) {
+ Stream.ExitBlock();
+ return;
+ }
+
// Abbrev for FS_PERMODULE.
BitCodeAbbrev *Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
Index: lib/LTO/LTO.cpp
===================================================================
--- lib/LTO/LTO.cpp
+++ lib/LTO/LTO.cpp
@@ -609,6 +609,26 @@
};
}
+// Given the original \p Path to an output file, replace any path
+// prefix matching \p OldPrefix with \p NewPrefix. Also, create the
+// resulting directory if it does not yet exist.
+std::string lto::getThinLTOOutputFile(const std::string &Path,
+ const std::string &OldPrefix,
+ const std::string &NewPrefix) {
+ if (OldPrefix.empty() && NewPrefix.empty())
+ return Path;
+ SmallString<128> NewPath(Path);
+ llvm::sys::path::replace_path_prefix(NewPath, OldPrefix, NewPrefix);
+ StringRef ParentPath = llvm::sys::path::parent_path(NewPath.str());
+ if (!ParentPath.empty()) {
+ // Make sure the new directory exists, creating it if necessary.
+ if (std::error_code EC = llvm::sys::fs::create_directories(ParentPath))
+ llvm::errs() << "warning: could not create directory '" << ParentPath
+ << "': " << EC.message() << '\n';
+ }
+ return NewPath.str();
+}
+
class WriteIndexesThinBackend : public ThinBackendProc {
std::string OldPrefix, NewPrefix;
bool ShouldEmitImportsFiles;
@@ -627,26 +647,6 @@
ShouldEmitImportsFiles(ShouldEmitImportsFiles),
LinkedObjectsFileName(LinkedObjectsFileName) {}
- /// Given the original \p Path to an output file, replace any path
- /// prefix matching \p OldPrefix with \p NewPrefix. Also, create the
- /// resulting directory if it does not yet exist.
- std::string getThinLTOOutputFile(const std::string &Path,
- const std::string &OldPrefix,
- const std::string &NewPrefix) {
- if (OldPrefix.empty() && NewPrefix.empty())
- return Path;
- SmallString<128> NewPath(Path);
- llvm::sys::path::replace_path_prefix(NewPath, OldPrefix, NewPrefix);
- StringRef ParentPath = llvm::sys::path::parent_path(NewPath.str());
- if (!ParentPath.empty()) {
- // Make sure the new directory exists, creating it if necessary.
- if (std::error_code EC = llvm::sys::fs::create_directories(ParentPath))
- llvm::errs() << "warning: could not create directory '" << ParentPath
- << "': " << EC.message() << '\n';
- }
- return NewPath.str();
- }
-
Error start(
unsigned Task, MemoryBufferRef MBRef,
const FunctionImporter::ImportMapTy &ImportList,
@@ -713,6 +713,16 @@
ModuleToDefinedGVSummaries(ThinLTO.ModuleMap.size());
ThinLTO.CombinedIndex.collectDefinedGVSummariesPerModule(
ModuleToDefinedGVSummaries);
+ // Create entries for any modules that didn't have any GV summaries
+ // (either they didn't have any GVs to start with, or we suppressed
+ // generation of the summaries because they e.g. had inline assembly
+ // uses that couldn't be promoted/renamed on export). This is so
+ // InProcessThinBackend::start can still launch a backend thread, which
+ // is passed the map of summaries for the module, without any special
+ // handling for this case.
+ for (auto &Mod : ThinLTO.ModuleMap)
+ if (!ModuleToDefinedGVSummaries.count(Mod.first))
+ ModuleToDefinedGVSummaries.try_emplace(Mod.first);
StringMap<FunctionImporter::ImportMapTy> ImportLists(
ThinLTO.ModuleMap.size());
Index: test/ThinLTO/X86/Inputs/emit_imports.ll
===================================================================
--- test/ThinLTO/X86/Inputs/emit_imports.ll
+++ test/ThinLTO/X86/Inputs/emit_imports.ll
@@ -1,3 +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 @g() {
entry:
ret void
Index: test/ThinLTO/X86/Inputs/empty.ll
===================================================================
--- /dev/null
+++ test/ThinLTO/X86/Inputs/empty.ll
@@ -0,0 +1,2 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
Index: test/ThinLTO/X86/emit_imports.ll
===================================================================
--- test/ThinLTO/X86/emit_imports.ll
+++ test/ThinLTO/X86/emit_imports.ll
@@ -1,7 +1,11 @@
; RUN: opt -module-summary %s -o %t1.bc
; RUN: opt -module-summary %p/Inputs/emit_imports.ll -o %t2.bc
-; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc
-; RUN: llvm-lto -thinlto-action=emitimports -thinlto-index %t.index.bc %t1.bc %t2.bc
+; Include a file with an empty module summary index, to ensure that the expected
+; output files are created regardless, for a distributed build system.
+; RUN: opt -module-summary %p/Inputs/empty.ll -o %t3.bc
+; RUN: rm -f %t3.bc.imports
+; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t1.bc %t2.bc %t3.bc
+; RUN: llvm-lto -thinlto-action=emitimports -thinlto-index %t.index.bc %t1.bc %t2.bc %t3.bc
; The imports file for this module contains the bitcode file for
; Inputs/emit_imports.ll
@@ -12,9 +16,13 @@
; The imports file for Input/emit_imports.ll is empty as it does not import anything.
; RUN: cat %t2.bc.imports | count 0
+; The imports file for Input/empty.ll is empty but should exist.
+; RUN: cat %t3.bc.imports | count 0
+
; RUN: rm -f %t1.thinlto.bc %t1.bc.imports
; RUN: rm -f %t2.thinlto.bc %t2.bc.imports
-; RUN: llvm-lto2 %t1.bc %t2.bc -o %t.o \
+; RUN: rm -f %t3.bc.thinlto.bc %t3.bc.imports
+; RUN: llvm-lto2 %t1.bc %t2.bc %t3.bc -o %t.o -save-temps \
; RUN: -thinlto-distributed-indexes \
; RUN: -r=%t1.bc,g, \
; RUN: -r=%t1.bc,f,px \
@@ -26,6 +34,15 @@
; The imports file for Input/emit_imports.ll is empty as it does not import anything.
; RUN: cat %t2.bc.imports | count 0
+; The imports file for Input/empty.ll is empty but should exist.
+; RUN: cat %t3.bc.imports | count 0
+
+; The index file should be created even for the input with an empty summary.
+; RUN: ls %t3.bc.thinlto.bc
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
declare void @g(...)
define void @f() {
Index: test/tools/gold/X86/thinlto_emit_imports.ll
===================================================================
--- test/tools/gold/X86/thinlto_emit_imports.ll
+++ test/tools/gold/X86/thinlto_emit_imports.ll
@@ -1,13 +1,17 @@
; Generate summary sections and test gold handling.
; RUN: opt -module-summary %s -o %t.o
; RUN: opt -module-summary %p/Inputs/thinlto.ll -o %t2.o
+; Include a file with an empty module summary index, to ensure that the expected
+; output files are created regardless, for a distributed build system.
+; RUN: opt -module-summary %p/Inputs/thinlto_empty.ll -o %t3.o
; Ensure gold generates imports files if requested for distributed backends.
+; RUN: rm -f %t3.o.imports %t3.o.thinlto.bc
; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
; RUN: --plugin-opt=thinlto \
; RUN: --plugin-opt=thinlto-index-only \
; RUN: --plugin-opt=thinlto-emit-imports-files \
-; RUN: -shared %t.o %t2.o -o %t3
+; RUN: -shared %t.o %t2.o %t3.o -o %t4
; The imports file for this module contains the bitcode file for
; Inputs/thinlto.ll
@@ -18,6 +22,12 @@
; The imports file for Input/thinlto.ll is empty as it does not import anything.
; RUN: cat %t2.o.imports | count 0
+; The imports file for Input/thinlto_empty.ll is empty but should exist.
+; RUN: cat %t3.o.imports | count 0
+
+; The index file should be created even for the input with an empty summary.
+; RUN: ls %t3.o.thinlto.bc
+
declare void @g(...)
define void @f() {
Index: test/tools/gold/X86/v1.12/thinlto_emit_linked_objects.ll
===================================================================
--- test/tools/gold/X86/v1.12/thinlto_emit_linked_objects.ll
+++ test/tools/gold/X86/v1.12/thinlto_emit_linked_objects.ll
@@ -9,14 +9,26 @@
; be included in the link, and not %t2.o since it is within
; a library (--start-lib/--end-lib pair) and not strongly referenced.
; Note that the support for detecting this is in gold v1.12.
+; RUN: rm -f %t.o.thinlto.bc
+; RUN: rm -f %t2.o.thinlto.bc
+; RUN: rm -f %t.o.imports
+; RUN: rm -f %t2.o.imports
; RUN: %gold -plugin %llvmshlibdir/LLVMgold.so \
; RUN: --plugin-opt=thinlto \
; RUN: --plugin-opt=thinlto-index-only=%t3 \
+; RUN: --plugin-opt=thinlto-emit-imports-files \
; RUN: -m elf_x86_64 \
; RUN: -o %t4 \
; RUN: %t.o \
; RUN: --start-lib %t2.o --end-lib
+; Ensure that the expected output files are created, even for the file
+; the linker decided not to include in the link.
+; RUN: ls %t.o.thinlto.bc
+; RUN: ls %t2.o.thinlto.bc
+; RUN: ls %t.o.imports
+; RUN: ls %t2.o.imports
+
; RUN: cat %t3 | FileCheck %s
; CHECK: thinlto_emit_linked_objects.ll.tmp.o
; CHECK-NOT: thinlto_emit_linked_objects.ll.tmp2.o
Index: tools/gold/gold-plugin.cpp
===================================================================
--- tools/gold/gold-plugin.cpp
+++ tools/gold/gold-plugin.cpp
@@ -752,6 +752,34 @@
ParallelCodeGenParallelismLevel);
}
+// Write empty files that may be expected by a distributed build
+// system when invoked with thinlto_index_only. This is invoked when
+// the linker has decided not to include the given module in the
+// final link. Frequently the distributed build system will want to
+// confirm that all expected outputs are created based on all of the
+// modules provided to the linker.
+static void writeEmptyDistributedBuildOutputs(std::string &ModulePath,
+ std::string &OldPrefix,
+ std::string &NewPrefix) {
+ std::string NewModulePath =
+ getThinLTOOutputFile(ModulePath, OldPrefix, NewPrefix);
+ std::error_code EC;
+ {
+ raw_fd_ostream OS(NewModulePath + ".thinlto.bc", EC,
+ sys::fs::OpenFlags::F_None);
+ if (EC)
+ message(LDPL_FATAL, "Failed to write '%s': %s",
+ (NewModulePath + ".thinlto.bc").c_str(), EC.message().c_str());
+ }
+ if (options::thinlto_emit_imports_files) {
+ raw_fd_ostream OS(NewModulePath + ".imports", EC,
+ sys::fs::OpenFlags::F_None);
+ if (EC)
+ message(LDPL_FATAL, "Failed to write '%s': %s",
+ (NewModulePath + ".imports").c_str(), EC.message().c_str());
+ }
+}
+
/// gold informs us that all symbols have been read. At this point, we use
/// get_symbols to see if any of our definitions have been overridden by a
/// native object file. Then, perform optimization and codegen.
@@ -771,13 +799,22 @@
std::unique_ptr<LTO> Lto = createLTO();
+ std::string OldPrefix, NewPrefix;
+ if (options::thinlto_index_only)
+ getThinLTOOldAndNewPrefix(OldPrefix, NewPrefix);
+
for (claimed_file &F : Modules) {
if (options::thinlto && !HandleToInputFile.count(F.leader_handle))
HandleToInputFile.insert(std::make_pair(
F.leader_handle, llvm::make_unique<PluginInputFile>(F.handle)));
const void *View = getSymbolsAndView(F);
- if (!View)
+ if (!View) {
+ if (options::thinlto_index_only)
+ // Write empty output files that may be expected by the distributed
+ // build system.
+ writeEmptyDistributedBuildOutputs(F.name, OldPrefix, NewPrefix);
continue;
+ }
addModule(*Lto, F, View);
}