[lld][LTO] Teach LTO to print pipeline passes #101018

macurtis-amd · 2024-07-29T14:15:38Z

I found this useful while debugging code generation differences between old and new offloading drivers.
No functional change (intended).

github-actions · 2024-07-29T14:15:54Z

Thank you for submitting a Pull Request (PR) to the LLVM Project!

This PR will be automatically labeled and the relevant teams will be
notified.

If you wish to, you can add reviewers by using the "Reviewers" section on this page.

If this is not working for you, it is probably because you do not have write
permissions for the repository. In which case you can instead tag reviewers by
name in a comment by using @ followed by their GitHub username.

If you have received no comments on your PR for a week, you can request a review
by "ping"ing the PR by adding a comment “Ping”. The common courtesy "ping" rate
is once a week. Please remember that you are asking for valuable time from other developers.

If you have further questions, they may be answered by the LLVM GitHub User Guide.

You can also ask questions in a comment on this PR, on the LLVM Discord or on the forums.

llvmbot · 2024-07-29T14:16:24Z

@llvm/pr-subscribers-lld-elf

@llvm/pr-subscribers-lto

Author: None (macurtis-amd)

Changes

I found useful while debugging code generation differences between old and new offloading drivers.
No function change (intended).

Full diff: https://github.com/llvm/llvm-project/pull/101018.diff

7 Files Affected:

(modified) lld/ELF/Config.h (+1)
(modified) lld/ELF/Driver.cpp (+1)
(modified) lld/ELF/LTO.cpp (+1)
(modified) lld/ELF/Options.td (+2)
(added) lld/test/ELF/lto/print-pipeline-passes.ll (+15)
(modified) llvm/include/llvm/LTO/Config.h (+6-2)
(modified) llvm/lib/LTO/LTOBackend.cpp (+10)

diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 6abd929d2343d..65216a47ecbdf 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -260,6 +260,7 @@ struct Config {
   bool ignoreFunctionAddressEquality;
   bool ltoCSProfileGenerate;
   bool ltoPGOWarnMismatch;
+  bool ltoPrintPipelinePasses;
   bool ltoDebugPassManager;
   bool ltoEmitAsm;
   bool ltoUniqueBasicBlockSectionNames;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 7e0a5a1937c7f..814145ae41d95 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1313,6 +1313,7 @@ static void readConfigs(opt::InputArgList &args) {
   config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
                                             OPT_no_lto_pgo_warn_mismatch, true);
+  config->ltoPrintPipelinePasses = args.hasArg(OPT_lto_print_pipeline_passes);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
   config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
index 935d0a9eab9ee..0e56ee4a86f88 100644
--- a/lld/ELF/LTO.cpp
+++ b/lld/ELF/LTO.cpp
@@ -127,6 +127,7 @@ static lto::Config createConfig() {
   c.SampleProfile = std::string(config->ltoSampleProfile);
   for (StringRef pluginFn : config->passPlugins)
     c.PassPlugins.push_back(std::string(pluginFn));
+  c.PrintPipelinePasses = config->ltoPrintPipelinePasses;
   c.DebugPassManager = config->ltoDebugPassManager;
   c.DwoDir = std::string(config->dwoDir);
 
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
index 74733efb28ff5..49a86c316ec46 100644
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -610,6 +610,8 @@ def lto: JJ<"lto=">, HelpText<"Set LTO backend">,
                  MetaVarName<"[full,thin]">;
 def lto_aa_pipeline: JJ<"lto-aa-pipeline=">,
   HelpText<"AA pipeline to run during LTO. Used in conjunction with -lto-newpm-passes">;
+def lto_print_pipeline_passes: FF<"lto-print-pipeline-passes">,
+  HelpText<"Print a '-passes' compatible string describing the LTO pipeline (best-effort only).">;
 def lto_debug_pass_manager: FF<"lto-debug-pass-manager">,
   HelpText<"Debug new pass manager">;
 def lto_emit_asm: FF<"lto-emit-asm">,
diff --git a/lld/test/ELF/lto/print-pipeline-passes.ll b/lld/test/ELF/lto/print-pipeline-passes.ll
new file mode 100644
index 0000000000000..0ff42eebba296
--- /dev/null
+++ b/lld/test/ELF/lto/print-pipeline-passes.ll
@@ -0,0 +1,15 @@
+; REQUIRES: x86
+
+; RUN: llvm-as %s -o %t.o
+; RUN: ld.lld --lto-print-pipeline-passes -o %t.out.o %t.o 2>&1 | FileCheck %s
+
+; CHECK: pipeline-passes: verify,{{.*}},verify
+
+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"
+
+@llvm.compiler.used = appending global [1 x ptr] [ptr @main], section "llvm.metadata"
+
+define hidden void @main() {
+  ret void
+}
diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
index 482b6e55a19d3..063bf5aae7639 100644
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -165,6 +165,10 @@ struct Config {
   /// Whether to emit the pass manager debuggging informations.
   bool DebugPassManager = false;
 
+  /// Print a '-passes' compatible string describing the pipeline (best-effort
+  /// only).
+  bool PrintPipelinePasses = false;
+
   /// Statistics output file path.
   std::string StatsFile;
 
@@ -302,7 +306,7 @@ struct LTOLLVMContext : LLVMContext {
   DiagnosticHandlerFunction DiagHandler;
 };
 
-}
-}
+} // namespace lto
+} // namespace llvm
 
 #endif
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index d5d642f0d25e6..949850a3c791b 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -335,6 +335,16 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
   if (!Conf.DisableVerify)
     MPM.addPass(VerifierPass());
 
+  if (Conf.PrintPipelinePasses) {
+    std::string PipelineStr;
+    raw_string_ostream OS(PipelineStr);
+    MPM.printPipeline(OS, [&PIC](StringRef ClassName) {
+      auto PassName = PIC.getPassNameForClassName(ClassName);
+      return PassName.empty() ? ClassName : PassName;
+    });
+    outs() << "pipeline-passes: " << PipelineStr << '\n';
+  }
+
   MPM.run(Mod, MAM);
 }

llvmbot · 2024-07-29T14:16:25Z

@llvm/pr-subscribers-lld

Author: None (macurtis-amd)

Changes

I found useful while debugging code generation differences between old and new offloading drivers.
No function change (intended).

Full diff: https://github.com/llvm/llvm-project/pull/101018.diff

7 Files Affected:

(modified) lld/ELF/Config.h (+1)
(modified) lld/ELF/Driver.cpp (+1)
(modified) lld/ELF/LTO.cpp (+1)
(modified) lld/ELF/Options.td (+2)
(added) lld/test/ELF/lto/print-pipeline-passes.ll (+15)
(modified) llvm/include/llvm/LTO/Config.h (+6-2)
(modified) llvm/lib/LTO/LTOBackend.cpp (+10)

diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
index 6abd929d2343d..65216a47ecbdf 100644
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -260,6 +260,7 @@ struct Config {
   bool ignoreFunctionAddressEquality;
   bool ltoCSProfileGenerate;
   bool ltoPGOWarnMismatch;
+  bool ltoPrintPipelinePasses;
   bool ltoDebugPassManager;
   bool ltoEmitAsm;
   bool ltoUniqueBasicBlockSectionNames;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 7e0a5a1937c7f..814145ae41d95 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1313,6 +1313,7 @@ static void readConfigs(opt::InputArgList &args) {
   config->ltoCSProfileFile = args.getLastArgValue(OPT_lto_cs_profile_file);
   config->ltoPGOWarnMismatch = args.hasFlag(OPT_lto_pgo_warn_mismatch,
                                             OPT_no_lto_pgo_warn_mismatch, true);
+  config->ltoPrintPipelinePasses = args.hasArg(OPT_lto_print_pipeline_passes);
   config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
   config->ltoEmitAsm = args.hasArg(OPT_lto_emit_asm);
   config->ltoNewPmPasses = args.getLastArgValue(OPT_lto_newpm_passes);
diff --git a/lld/ELF/LTO.cpp b/lld/ELF/LTO.cpp
index 935d0a9eab9ee..0e56ee4a86f88 100644
--- a/lld/ELF/LTO.cpp
+++ b/lld/ELF/LTO.cpp
@@ -127,6 +127,7 @@ static lto::Config createConfig() {
   c.SampleProfile = std::string(config->ltoSampleProfile);
   for (StringRef pluginFn : config->passPlugins)
     c.PassPlugins.push_back(std::string(pluginFn));
+  c.PrintPipelinePasses = config->ltoPrintPipelinePasses;
   c.DebugPassManager = config->ltoDebugPassManager;
   c.DwoDir = std::string(config->dwoDir);
 
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
index 74733efb28ff5..49a86c316ec46 100644
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -610,6 +610,8 @@ def lto: JJ<"lto=">, HelpText<"Set LTO backend">,
                  MetaVarName<"[full,thin]">;
 def lto_aa_pipeline: JJ<"lto-aa-pipeline=">,
   HelpText<"AA pipeline to run during LTO. Used in conjunction with -lto-newpm-passes">;
+def lto_print_pipeline_passes: FF<"lto-print-pipeline-passes">,
+  HelpText<"Print a '-passes' compatible string describing the LTO pipeline (best-effort only).">;
 def lto_debug_pass_manager: FF<"lto-debug-pass-manager">,
   HelpText<"Debug new pass manager">;
 def lto_emit_asm: FF<"lto-emit-asm">,
diff --git a/lld/test/ELF/lto/print-pipeline-passes.ll b/lld/test/ELF/lto/print-pipeline-passes.ll
new file mode 100644
index 0000000000000..0ff42eebba296
--- /dev/null
+++ b/lld/test/ELF/lto/print-pipeline-passes.ll
@@ -0,0 +1,15 @@
+; REQUIRES: x86
+
+; RUN: llvm-as %s -o %t.o
+; RUN: ld.lld --lto-print-pipeline-passes -o %t.out.o %t.o 2>&1 | FileCheck %s
+
+; CHECK: pipeline-passes: verify,{{.*}},verify
+
+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"
+
+@llvm.compiler.used = appending global [1 x ptr] [ptr @main], section "llvm.metadata"
+
+define hidden void @main() {
+  ret void
+}
diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
index 482b6e55a19d3..063bf5aae7639 100644
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -165,6 +165,10 @@ struct Config {
   /// Whether to emit the pass manager debuggging informations.
   bool DebugPassManager = false;
 
+  /// Print a '-passes' compatible string describing the pipeline (best-effort
+  /// only).
+  bool PrintPipelinePasses = false;
+
   /// Statistics output file path.
   std::string StatsFile;
 
@@ -302,7 +306,7 @@ struct LTOLLVMContext : LLVMContext {
   DiagnosticHandlerFunction DiagHandler;
 };
 
-}
-}
+} // namespace lto
+} // namespace llvm
 
 #endif
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index d5d642f0d25e6..949850a3c791b 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -335,6 +335,16 @@ static void runNewPMPasses(const Config &Conf, Module &Mod, TargetMachine *TM,
   if (!Conf.DisableVerify)
     MPM.addPass(VerifierPass());
 
+  if (Conf.PrintPipelinePasses) {
+    std::string PipelineStr;
+    raw_string_ostream OS(PipelineStr);
+    MPM.printPipeline(OS, [&PIC](StringRef ClassName) {
+      auto PassName = PIC.getPassNameForClassName(ClassName);
+      return PassName.empty() ? ClassName : PassName;
+    });
+    outs() << "pipeline-passes: " << PipelineStr << '\n';
+  }
+
   MPM.run(Mod, MAM);
 }

teresajohnson · 2024-07-29T15:10:26Z

It looks like from clang this is triggered by an internal LLVM option (-print-pipeline-passes). Since this is a debugging functionality, rather than add another LLD option can you just make the LTO code be guarded by the same option? Then it can just be triggered via -Wl,-mllvm,-print-pipeline-passes, and the advantage is that the internal option can then also be used from other linkers such as gold.

macurtis-amd · 2024-07-29T16:52:45Z

It looks like from clang this is triggered by an internal LLVM option (-print-pipeline-passes). Since this is a debugging functionality, rather than add another LLD option can you just make the LTO code be guarded by the same option? Then it can just be triggered via -Wl,-mllvm,-print-pipeline-passes, and the advantage is that the internal option can then also be used from other linkers such as gold.

Thanks for the feedback. Latest revision reuses -print-pipeline-passes as you suggested.

teresajohnson

Thanks - since this is now in LTO just make an LTO test using something like either llvm-lto or llvm-lto2 instead of lld. See examples in llvm/test/LTO/X86

llvm/lib/LTO/LTOBackend.cpp

macurtis-amd · 2024-07-29T19:35:12Z

Thanks - since this is now in LTO just make an LTO test using something like either llvm-lto or llvm-lto2 instead of lld. See examples in llvm/test/LTO/X86

Removed lld test and added LTO test. No more lld changes :)

teresajohnson

lgtm

github-actions · 2024-07-29T19:56:58Z

@macurtis-amd Congratulations on having your first Pull Request (PR) merged into the LLVM Project!

Your changes will be combined with recent changes from other authors, then tested
by our build bots. If there is a problem with a build, you may receive a report in an email or a comment on this PR.

Please check whether problems have been caused by your change specifically, as
the builds can include changes from many authors. It is not uncommon for your
change to be included in a build that fails due to someone else's changes, or
infrastructure issues.

How to do this, and the rest of the post-merge process, is covered in detail here.

If your change does cause a problem, it may be reverted, or you can revert it yourself.
This is a normal part of LLVM development. You can fix your changes and open a new PR to merge them again.

If you don't get any reports, no action is required from you. Your changes are working as expected, well done!

github-actions · 2024-07-29T19:57:15Z

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 2c376fe96c83443c15e6485d043ebe321904546b 08c24724c395e925c2d2ed043140bb370c3c679e --extensions h,cpp -- llvm/include/llvm/Passes/PassBuilder.h llvm/lib/LTO/LTOBackend.cpp llvm/tools/llc/NewPMDriver.cpp llvm/tools/opt/NewPMDriver.cpp

View the diff from clang-format here.

diff --git a/llvm/include/llvm/Passes/PassBuilder.h b/llvm/include/llvm/Passes/PassBuilder.h
index e1d78a8685..6935ca0536 100644
--- a/llvm/include/llvm/Passes/PassBuilder.h
+++ b/llvm/include/llvm/Passes/PassBuilder.h
@@ -947,7 +947,6 @@ public:
 
 /// Common option used by multiple tools to print pipeline passes
 extern cl::opt<bool> PrintPipelinePasses;
-
 }
 
 #endif

llvmbot added lld lld:ELF LTO Link time optimization (regular/full LTO or ThinLTO) labels Jul 29, 2024

macurtis-amd mentioned this pull request Jul 29, 2024

Add debug options to clang-linker-wrapper #101008

Closed

macurtis-amd force-pushed the lld-print-pipeline-passes branch from 57fd63e to 913ed28 Compare July 29, 2024 16:50

teresajohnson reviewed Jul 29, 2024

View reviewed changes

llvm/lib/LTO/LTOBackend.cpp Outdated Show resolved Hide resolved

[LTO] Teach LTO to print pipeline passes

08c2472

macurtis-amd force-pushed the lld-print-pipeline-passes branch from 913ed28 to 08c2472 Compare July 29, 2024 19:32

teresajohnson approved these changes Jul 29, 2024

View reviewed changes

ronlieb merged commit 26e455b into llvm:main Jul 29, 2024
3 of 6 checks passed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[lld][LTO] Teach LTO to print pipeline passes #101018

[lld][LTO] Teach LTO to print pipeline passes #101018

Uh oh!

macurtis-amd commented Jul 29, 2024 •

edited

Loading

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

llvmbot commented Jul 29, 2024 •

edited

Loading

Uh oh!

llvmbot commented Jul 29, 2024

Uh oh!

teresajohnson commented Jul 29, 2024

Uh oh!

macurtis-amd commented Jul 29, 2024

Uh oh!

teresajohnson left a comment

Uh oh!

Uh oh!

macurtis-amd commented Jul 29, 2024

Uh oh!

teresajohnson left a comment

Uh oh!

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

Uh oh!

[lld][LTO] Teach LTO to print pipeline passes #101018

[lld][LTO] Teach LTO to print pipeline passes #101018

Uh oh!

Conversation

macurtis-amd commented Jul 29, 2024 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

llvmbot commented Jul 29, 2024 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

llvmbot commented Jul 29, 2024

Uh oh!

teresajohnson commented Jul 29, 2024

Uh oh!

macurtis-amd commented Jul 29, 2024

Uh oh!

teresajohnson left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

macurtis-amd commented Jul 29, 2024

Uh oh!

teresajohnson left a comment

Choose a reason for hiding this comment

Uh oh!

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

github-actions bot commented Jul 29, 2024

Uh oh!

Uh oh!

macurtis-amd commented Jul 29, 2024 •

edited

Loading

llvmbot commented Jul 29, 2024 •

edited

Loading