[lld] Add --lto-debug-pass-manager option

Add support for printing the passes run for LTO. Both ELF and COFF have `--lto-debug-pass-manager` (`-ltodebugpassmanager`) to print the compiler passes run during LTO. This is useful to check that a certain compiler pass is run in a test, e.g., https://reviews.llvm.org/D151589 Reviewed By: #lld-macho, MaskRay, int3 Differential Revision: https://reviews.llvm.org/D151746
llvm · May 31, 2023 · f924104 · f924104
1 parent 1cf5188
commit f924104
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diff --git a/lld/MachO/Config.h b/lld/MachO/Config.h
@@ -205,6 +205,7 @@ struct Configuration {
   // so use a vector instead of a map.
   std::vector<SectionAlign> sectionAlignments;
   std::vector<SegmentProtection> segmentProtections;
+  bool ltoDebugPassManager = false;
 
   bool callGraphProfileSort = false;
   llvm::StringRef printSymbolOrder;

diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
@@ -1636,6 +1636,7 @@ bool macho::link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
   for (const Arg *arg : args.filtered(OPT_ignore_auto_link_option))
     config->ignoreAutoLinkOptions.insert(arg->getValue());
   config->strictAutoLink = args.hasArg(OPT_strict_auto_link);
+  config->ltoDebugPassManager = args.hasArg(OPT_lto_debug_pass_manager);
 
   for (const Arg *arg : args.filtered(OPT_alias)) {
     config->aliasedSymbols.push_back(

diff --git a/lld/MachO/LTO.cpp b/lld/MachO/LTO.cpp
@@ -68,6 +68,7 @@ static lto::Config createConfig() {
 
   c.TimeTraceEnabled = config->timeTraceEnabled;
   c.TimeTraceGranularity = config->timeTraceGranularity;
+  c.DebugPassManager = config->ltoDebugPassManager;
   c.OptLevel = config->ltoo;
   c.CGOptLevel = config->ltoCgo;
   if (config->saveTemps)

diff --git a/lld/MachO/Options.td b/lld/MachO/Options.td
@@ -124,6 +124,8 @@ def strict_auto_link : Flag<["--"], "strict-auto-link">,
 def check_category_conflicts : Flag<["--"], "check-category-conflicts">,
     HelpText<"Check for conflicts between category & class methods">,
     Group<grp_lld>;
+def lto_debug_pass_manager: Flag<["--"], "lto-debug-pass-manager">,
+    HelpText<"Debug new pass manager">, Group<grp_lld>;
 
 // This is a complete Options.td compiled from Apple's ld(1) manpage
 // dated 2018-03-07 and cross checked with ld64 source code in repo

diff --git a/lld/test/MachO/new-pass-manager.ll b/lld/test/MachO/new-pass-manager.ll
@@ -0,0 +1,14 @@
+; REQUIRES: x86
+
+; RUN: llvm-as %s -o %t.o
+; RUN: %lld -dylib --lto-debug-pass-manager -o /dev/null %t.o 2>&1 | FileCheck %s
+
+; CHECK: Running pass: GlobalOptPass
+
+target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-darwin"
+
+define void @foo() {
+entry:
+  ret void
+}