[ELF] accept thinlto options without --plugin-opt= prefix

[inglorion]

Summary

When support for ThinLTO was first added to lld, the options that
control it were prefixed with --plugin-opt= for compatibility with
an existing implementation as a linker plugin. This change enables
shorter versions of the options to be used, as follows:

New                              Existing
-thinlto-emit-imports-files      --plugin-opt=thinlto-emit-imports-files
-thinlto-index-only              --plugin-opt=thinlto-index-only
-thinlto-index-only=             --plugin-opt=thinlto-index-only=
-thinlto-object-suffix-replace=  --plugin-opt=thinlto-object-suffix-replace=
-thinlto-prefix-replace=         --plugin-opt=thinlto-prefix-replace=
-lto-obj-path=                   --plugin-opt=obj-path=

The options with the --plugin-opt= prefix have been retained as aliases
for the shorter variants so that they continue to be accepted.

[MaskRay]

lld/test/ELF/lto/thinlto-emit-imports.ll

50

count 1 < %t1.o.imports
FileCheck %s --check-prefix=IMPORTS1 < %t1.o.imports

or

FileCheck %s --check-prefix=IMPORTS1 --implicit-check-not {{.}} < %t1.o.imports

lld/test/ELF/lto/thinlto-index-file.ll

16

%t4 -> /dev/null

lld/test/ELF/lto/thinlto-obj-path.ll

15

%t3 -> /dev/null

[inglorion]

@MaskRay's comments. Thanks! I've changed the original code to match.

[ruiu]

lld/ELF/Driver.cpp

760

Maybe getAliasSpelling is better?

764

nit: no else after return

You can combine the definition and the if statement as this:

if (const llvm::opt::Arg *alias = arg->getAlias())
  ...

lld/ELF/Options.td

525–550

These alias flags are not accessed from the code by name, so you can omit names like this:

def: J<"plugin-opt=thinlto-prefix-replace=">,
  Alias<...

which makes it clear that they are really aliases.

[inglorion]

@ruiu's comments (thanks!)

[ruiu]

LGTM

lld/ELF/Driver.cpp

760–761

I believe you can omit llvm::.

[inglorion]

Thanks! Removing unnecessary llvm:: prefix before commit.

lld/ELF/Driver.cpp

if (s == "none")
     return false;
   if (s != "zlib")
     error("unknown --compress-debug-sections value: " + s);
   if (!zlib::isAvailable())
     error("--compress-debug-sections: zlib is not available");
   return true;
 }
 
+static StringRef aliasSpelling(llvm::opt::Arg *arg) {
+  const llvm::opt::Arg *alias = arg->getAlias();
+  if (alias)
+    return alias->getSpelling();
+  else
+    return arg->getSpelling();
+}
+
 static std::pair<StringRef, StringRef> getOldNewOptions(opt::InputArgList &args,
                                                         unsigned id) {
   auto *arg = args.getLastArg(id);
   if (!arg)
     return {"", ""};
 
   StringRef s = arg->getValue();
   std::pair<StringRef, StringRef> ret = s.split(';');
   if (ret.second.empty())
-    error(arg->getSpelling() + " expects 'old;new' format, but got " + s);
+    error(aliasSpelling(arg) + " expects 'old;new' format, but got " + s);
   return ret;
 }
 
 // Parse the symbol ordering file and warn for any duplicate entries.
 static std::vector<StringRef> getSymbolOrderingFile(MemoryBufferRef mb) {
   SetVector<StringRef> names;
   for (StringRef s : args::getLines(mb))
     if (!names.insert(s) && config->warnSymbolOrdering)
static void readConfigs(opt::InputArgList &args) {
   config->init = args.getLastArgValue(OPT_init, "_init");
   config->ltoAAPipeline = args.getLastArgValue(OPT_lto_aa_pipeline);
   config->ltoCSProfileGenerate = args.hasArg(OPT_lto_cs_profile_generate);
   config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->ltoNewPassManager = args.hasArg(OPT_lto_new_pass_manager);
   config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
-  config->ltoObjPath = args.getLastArgValue(OPT_plugin_opt_obj_path_eq);
+  config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
   config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
   config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
   config->mapFile = args.getLastArgValue(OPT_Map);
   config->mipsGotSize = args::getInteger(args, OPT_mips_got_size, 0xfff0);
   config->mergeArmExidx =
       args.hasFlag(OPT_merge_exidx_entries, OPT_no_merge_exidx_entries, true);
   config->nmagic = args.hasFlag(OPT_nmagic, OPT_no_nmagic, false);
   config->noinhibitExec = args.hasArg(OPT_noinhibit_exec);
static void readConfigs(opt::InputArgList &args) {
   config->strip = getStrip(args);
   config->sysroot = args.getLastArgValue(OPT_sysroot);
   config->target1Rel = args.hasFlag(OPT_target1_rel, OPT_target1_abs, false);
   config->target2 = getTarget2(args);
   config->thinLTOCacheDir = args.getLastArgValue(OPT_thinlto_cache_dir);
   config->thinLTOCachePolicy = CHECK(
       parseCachePruningPolicy(args.getLastArgValue(OPT_thinlto_cache_policy)),
       "--thinlto-cache-policy: invalid cache policy");
-  config->thinLTOEmitImportsFiles =
-      args.hasArg(OPT_plugin_opt_thinlto_emit_imports_files);
-  config->thinLTOIndexOnly = args.hasArg(OPT_plugin_opt_thinlto_index_only) ||
-                             args.hasArg(OPT_plugin_opt_thinlto_index_only_eq);
-  config->thinLTOIndexOnlyArg =
-      args.getLastArgValue(OPT_plugin_opt_thinlto_index_only_eq);
+  config->thinLTOEmitImportsFiles = args.hasArg(OPT_thinlto_emit_imports_files);
+  config->thinLTOIndexOnly = args.hasArg(OPT_thinlto_index_only) ||
+                             args.hasArg(OPT_thinlto_index_only_eq);
+  config->thinLTOIndexOnlyArg = args.getLastArgValue(OPT_thinlto_index_only_eq);
   config->thinLTOJobs = args::getInteger(args, OPT_thinlto_jobs, -1u);
   config->thinLTOObjectSuffixReplace =
-      getOldNewOptions(args, OPT_plugin_opt_thinlto_object_suffix_replace_eq);
+      getOldNewOptions(args, OPT_thinlto_object_suffix_replace_eq);
   config->thinLTOPrefixReplace =
-      getOldNewOptions(args, OPT_plugin_opt_thinlto_prefix_replace_eq);
+      getOldNewOptions(args, OPT_thinlto_prefix_replace_eq);
   config->trace = args.hasArg(OPT_trace);
   config->undefined = args::getStrings(args, OPT_undefined);
   config->undefinedVersion =
       args.hasFlag(OPT_undefined_version, OPT_no_undefined_version, true);
   config->useAndroidRelrTags = args.hasFlag(
       OPT_use_android_relr_tags, OPT_no_use_android_relr_tags, false);
   config->unresolvedSymbols = getUnresolvedSymbolPolicy(args);
   config->warnBackrefs =

lld/ELF/Options.td

 def lto_O: J<"lto-O">, MetaVarName<"<opt-level>">,
   HelpText<"Optimization level for LTO">;
 def lto_partitions: J<"lto-partitions=">,
   HelpText<"Number of LTO codegen partitions">;
 def lto_cs_profile_generate: F<"lto-cs-profile-generate">,
   HelpText<"Perform context senstive PGO instrumentation">;
 def lto_cs_profile_file: J<"lto-cs-profile-file=">,
   HelpText<"Context sensitive profile file path">;
+def lto_obj_path_eq: J<"lto-obj-path=">;
 def lto_sample_profile: J<"lto-sample-profile=">,
   HelpText<"Sample profile file path">;
 def disable_verify: F<"disable-verify">;
 defm mllvm: Eq<"mllvm", "Additional arguments to forward to LLVM's option processing">;
 def opt_remarks_filename: Separate<["--"], "opt-remarks-filename">,
   HelpText<"YAML output file for optimization remarks">;
 def opt_remarks_passes: Separate<["--"], "opt-remarks-passes">,
   HelpText<"Regex for the passes that need to be serialized to the output file">;
 def opt_remarks_with_hotness: Flag<["--"], "opt-remarks-with-hotness">,
   HelpText<"Include hotness information in the optimization remarks file">;
 def opt_remarks_format: Separate<["--"], "opt-remarks-format">,
   HelpText<"The format used for serializing remarks (default: YAML)">;
 defm plugin_opt: Eq<"plugin-opt", "specifies LTO options for compatibility with GNU linkers">;
 def save_temps: F<"save-temps">;
 def thinlto_cache_dir: J<"thinlto-cache-dir=">,
   HelpText<"Path to ThinLTO cached object file directory">;
 defm thinlto_cache_policy: Eq<"thinlto-cache-policy", "Pruning policy for the ThinLTO cache">;
+def thinlto_emit_imports_files: F<"thinlto-emit-imports-files">;
+def thinlto_index_only: F<"thinlto-index-only">;
+def thinlto_index_only_eq: J<"thinlto-index-only=">;
 def thinlto_jobs: J<"thinlto-jobs=">, HelpText<"Number of ThinLTO jobs">;
+def thinlto_object_suffix_replace_eq: J<"thinlto-object-suffix-replace=">;
+def thinlto_prefix_replace_eq: J<"thinlto-prefix-replace=">;
 
 def: J<"plugin-opt=O">, Alias<lto_O>, HelpText<"Alias for -lto-O">;
 def: F<"plugin-opt=debug-pass-manager">,
   Alias<lto_debug_pass_manager>, HelpText<"Alias for -lto-debug-pass-manager">;
 def: F<"plugin-opt=disable-verify">, Alias<disable_verify>, HelpText<"Alias for -disable-verify">;
 def plugin_opt_dwo_dir_eq: J<"plugin-opt=dwo_dir=">,
   HelpText<"Directory to store .dwo files when LTO and debug fission are used">;
 def plugin_opt_emit_llvm: F<"plugin-opt=emit-llvm">;
 def: J<"plugin-opt=jobs=">, Alias<thinlto_jobs>, HelpText<"Alias for -thinlto-jobs">;
 def: J<"plugin-opt=lto-partitions=">, Alias<lto_partitions>, HelpText<"Alias for -lto-partitions">;
 def plugin_opt_mcpu_eq: J<"plugin-opt=mcpu=">;
 def: F<"plugin-opt=new-pass-manager">,
   Alias<lto_new_pass_manager>, HelpText<"Alias for -lto-new-pass-manager">;
-def plugin_opt_obj_path_eq: J<"plugin-opt=obj-path=">;
 def: F<"plugin-opt=cs-profile-generate">,
   Alias<lto_cs_profile_generate>, HelpText<"Alias for -lto-cs-profile-generate">;
 def: J<"plugin-opt=cs-profile-path=">,
   Alias<lto_cs_profile_file>, HelpText<"Alias for -lto-cs-profile-file">;
+def plugin_opt_obj_path_eq: J<"plugin-opt=obj-path=">,
+    Alias<lto_obj_path_eq>,
+    HelpText<"Alias for -lto-obj-path=">;
 def: J<"plugin-opt=sample-profile=">,
   Alias<lto_sample_profile>, HelpText<"Alias for -lto-sample-profile">;
 def: F<"plugin-opt=save-temps">, Alias<save_temps>, HelpText<"Alias for -save-temps">;
-def plugin_opt_thinlto_emit_imports_files: F<"plugin-opt=thinlto-emit-imports-files">;
-def plugin_opt_thinlto_index_only: F<"plugin-opt=thinlto-index-only">;
-def plugin_opt_thinlto_index_only_eq: J<"plugin-opt=thinlto-index-only=">;
-def plugin_opt_thinlto_object_suffix_replace_eq: J<"plugin-opt=thinlto-object-suffix-replace=">;
-def plugin_opt_thinlto_prefix_replace_eq: J<"plugin-opt=thinlto-prefix-replace=">;
+def plugin_opt_thinlto_emit_imports_files:
+    F<"plugin-opt=thinlto-emit-imports-files">,
+    Alias<thinlto_emit_imports_files>,
+    HelpText<"Alias for -thinlto-emit-imports-files">;
+def plugin_opt_thinlto_index_only:
+    F<"plugin-opt=thinlto-index-only">,
+    Alias<thinlto_index_only>,
+    HelpText<"Alias for -thinlto-index-only">;
+def plugin_opt_thinlto_index_only_eq:
+    J<"plugin-opt=thinlto-index-only=">,
+    Alias<thinlto_index_only_eq>,
+    HelpText<"Alias for -thinlto-index-only=">;
+def plugin_opt_thinlto_object_suffix_replace_eq:
+    J<"plugin-opt=thinlto-object-suffix-replace=">,
+    Alias<thinlto_object_suffix_replace_eq>,
+    HelpText<"Alias for -thinlto-object-suffix-replace=">;
+def plugin_opt_thinlto_prefix_replace_eq:
+    J<"plugin-opt=thinlto-prefix-replace=">,
+    Alias<thinlto_prefix_replace_eq>,
+    HelpText<"Alias for -thinlto-prefix-replace=">;
 
 // Ignore LTO plugin-related options.
 // clang -flto passes -plugin and -plugin-opt to the linker. This is required
 // for ld.gold and ld.bfd to get LTO working. But it's not for lld which doesn't
 // rely on a plugin. Instead of detecting which linker is used on clang side we
 // just ignore the option on lld side as it's easier. In fact, the linker could
 // be called 'ld' and understanding which linker is used would require parsing of
 // --version output.

lld/test/ELF/lto/thinlto-emit-imports.ll

 ; RUN: rm -f %t1.o.imports
 ; RUN: rm -f %t2.o.imports
 ; RUN: rm -f %t3.o.imports
 ; RUN: ld.lld --plugin-opt=thinlto-emit-imports-files -shared %t1.o %t2.o %t3.o -o %t4
 ; RUN: not ls %t1.o.imports
 ; RUN: not ls %t2.o.imports
 ; RUN: not ls %t3.o.imports
 
+; Check that imports files are generated also when -thinlto-index-only
+; is specified without --plugin-opt=.
+; RUN: rm -f %t1.o.imports
+; RUN: ld.lld -thinlto-index-only -thinlto-emit-imports-files -shared %t1.o %t2.o %t3.o -o %t4
+; RUN: cat %t1.o.imports | count 1
+; RUN: cat %t1.o.imports | FileCheck %s --check-prefix=IMPORTS1
+
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 declare void @g(...)
 
 define void @f() {
 entry:
   call void (...) @g()
   ret void
 }

lld/test/ELF/lto/thinlto-index-file.ll

 ; REQUIRES: x86
 
 ; Basic ThinLTO tests.
 ; RUN: opt -module-summary %s -o %t1.o
 ; RUN: opt -module-summary %p/Inputs/thinlto.ll -o %t2.o
 ; RUN: opt -module-summary %p/Inputs/thinlto_empty.ll -o %t3.o
 
 ; Ensure lld writes linked files to linked objects file
 ; RUN: ld.lld --plugin-opt=thinlto-index-only=%t.idx -shared %t1.o %t2.o %t3.o -o %t4
 ; RUN: FileCheck %s < %t.idx
 ; CHECK: {{.*}}thinlto-index-file.ll.tmp1.o
 ; CHECK: {{.*}}thinlto-index-file.ll.tmp2.o
 ; CHECK: {{.*}}thinlto-index-file.ll.tmp3.o
 
+; Check that this also works without the --plugin-opt= prefix.
+; RUN: ld.lld -thinlto-index-only=%t.idx -shared %t1.o %t2.o %t3.o -o %t4
+; RUN: FileCheck %s < %t.idx
+
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 declare void @g(...)
 
 define void @f() {
 entry:
   call void (...) @g()
   ret void
 }

lld/test/ELF/lto/thinlto-obj-path.ll

 ; REQUIRES: x86
 
 ; RUN: opt -module-summary %s -o %t1.o
 ; RUN: opt -module-summary %p/Inputs/thinlto.ll -o %t2.o
 
 ; Test to ensure that thinlto-index-only with obj-path creates the file.
 ; RUN: rm -f %t4.o
 ; RUN: ld.lld --plugin-opt=thinlto-index-only --plugin-opt=obj-path=%t4.o -shared %t1.o %t2.o -o %t3
 ; RUN: llvm-readobj -h %t4.o | FileCheck %s
 ; RUN: llvm-nm %t4.o 2>&1 | FileCheck %s -check-prefix=NO-SYMBOLS
 ; NO-SYMBOLS: no symbols
 
+; Check that this also works without the --plugin-opt= prefix.
+; RUN: rm -f %t4.o
+; RUN: ld.lld -thinlto-index-only -lto-obj-path=%t4.o -shared %t1.o %t2.o -o %t3
+; RUN: llvm-readobj -h %t4.o | FileCheck %s
+
 ; CHECK: Format: ELF64-x86-64
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 declare void @g(...)
 
 define void @f() {
 entry:
   call void (...) @g()
   ret void
 }

lld/test/ELF/lto/thinlto-object-suffix-replace.ll

 ; of the resulting index to the above dump to ensure they are identical.
 ; RUN: rm -f %t1.o.thinlto.bc
 ; Make sure it isn't inadvertently using the regular bitcode file.
 ; RUN: rm -f %t1.o
 ; RUN: ld.lld --plugin-opt=thinlto-index-only \
 ; RUN: --plugin-opt=thinlto-object-suffix-replace=".thinlink.bc;.o" \
 ; RUN: -shared %t1.thinlink.bc -o %t3
 ; RUN: diff %t1.o.thinlto.bc.orig %t1.o.thinlto.bc
+; Also check that this works without the --plugin-opt= prefix.
+; RUN: ld.lld -thinlto-index-only \
+; RUN: -thinlto-object-suffix-replace=".thinlink.bc;.o" \
+; RUN: -shared %t1.thinlink.bc -o %t3
+; RUN: diff %t1.o.thinlto.bc.orig %t1.o.thinlto.bc
 
 ; Ensure lld generates error if object suffix replace option does not have 'old;new' format
 ; RUN: rm -f %t1.o.thinlto.bc
 ; RUN: not ld.lld --plugin-opt=thinlto-index-only \
 ; RUN: --plugin-opt=thinlto-object-suffix-replace="abc:def" -shared %t1.thinlink.bc \
 ; RUN: -o %t3 2>&1 | FileCheck %s --check-prefix=ERR1
 ; ERR1: --plugin-opt=thinlto-object-suffix-replace= expects 'old;new' format, but got abc:def
 

lld/test/ELF/lto/thinlto-prefix-replace.ll

 ; REQUIRES: x86
 ; Check that changing the output path via thinlto-prefix-replace works
 ; RUN: mkdir -p %t/oldpath
 ; RUN: opt -module-summary %s -o %t/oldpath/thinlto_prefix_replace.o
 
 ; Ensure that there is no existing file at the new path, so we properly
 ; test the creation of the new file there.
 ; RUN: rm -f %t/newpath/thinlto_prefix_replace.o.thinlto.bc
 ; RUN: ld.lld --plugin-opt=thinlto-index-only --plugin-opt=thinlto-prefix-replace="%t/oldpath/;%t/newpath/" -shared %t/oldpath/thinlto_prefix_replace.o -o %t/thinlto_prefix_replace
 ; RUN: ls %t/newpath/thinlto_prefix_replace.o.thinlto.bc
 
+; Check that this also works without the --plugin-opt= prefix.
+; RUN: rm -f %t/newpath/thinlto_prefix_replace.o.thinlto.bc
+; RUN: ld.lld -thinlto-index-only -thinlto-prefix-replace="%t/oldpath/;%t/newpath/" -shared %t/oldpath/thinlto_prefix_replace.o -o %t/thinlto_prefix_replace
+; RUN: ls %t/newpath/thinlto_prefix_replace.o.thinlto.bc
+
 ; Ensure that lld generates error if prefix replace option does not have 'old;new' format
 ; RUN: rm -f %t/newpath/thinlto_prefix_replace.o.thinlto.bc
 ; RUN: not ld.lld --plugin-opt=thinlto-index-only --plugin-opt=thinlto-prefix-replace=abc:def -shared %t/oldpath/thinlto_prefix_replace.o -o %t/thinlto_prefix_replace 2>&1 | FileCheck %s --check-prefix=ERR
 ; ERR: --plugin-opt=thinlto-prefix-replace= expects 'old;new' format, but got abc:def
 
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
 define void @f() {
 entry:
   ret void
 }