[CSSPGO] LTO option for pseudo probe

Adding a lld option to support emitting pseudo probe metadata in LTO mode.

Reviewed By: MaskRay, wmi, wenlei

Differential Revision: https://reviews.llvm.org/D95056

lld/ELF/Config.h

@@ -175,6 +175,7 @@ struct Configuration {
   bool ltoDebugPassManager;
   bool ltoEmitAsm;
   bool ltoNewPassManager;
+  bool ltoPseudoProbeForProfiling;
   bool ltoUniqueBasicBlockSectionNames;
   bool ltoWholeProgramVisibility;
   bool mergeArmExidx;

lld/ELF/Driver.cpp

@@ -1005,6 +1005,8 @@ static void readConfigs(opt::InputArgList &args) {
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   config->ltoObjPath = args.getLastArgValue(OPT_lto_obj_path_eq);
   config->ltoPartitions = args::getInteger(args, OPT_lto_partitions, 1);
+  config->ltoPseudoProbeForProfiling =
+      args.hasArg(OPT_lto_pseudo_probe_for_profiling);
   config->ltoSampleProfile = args.getLastArgValue(OPT_lto_sample_profile);
   config->ltoBasicBlockSections =
       args.getLastArgValue(OPT_lto_basic_block_sections);

lld/ELF/LTO.cpp

@@ -112,6 +112,7 @@ static lto::Config createConfig() {
     }
   }
 
+  c.Options.PseudoProbeForProfiling = config->ltoPseudoProbeForProfiling;
   c.Options.UniqueBasicBlockSectionNames =
       config->ltoUniqueBasicBlockSectionNames;
 

lld/ELF/Options.td

@@ -550,6 +550,8 @@ def lto_sample_profile: JJ<"lto-sample-profile=">,
 defm lto_whole_program_visibility: BB<"lto-whole-program-visibility",
   "Asserts that the LTO link has whole program visibility",
   "Asserts that the LTO link does not have whole program visibility">;
+def lto_pseudo_probe_for_profiling: F<"lto-pseudo-probe-for-profiling">,
+  HelpText<"Emit pseudo probes for sample profiling">;
 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">,
@@ -623,6 +625,8 @@ def: F<"plugin-opt=opt-remarks-with-hotness">,
 def: J<"plugin-opt=opt-remarks-hotness-threshold=">,
   Alias<opt_remarks_hotness_threshold>,
   HelpText<"Alias for --opt-remarks-hotness-threshold">;
+def: J<"plugin-opt=pseudo-probe-for-profiling">,
+  Alias<lto_pseudo_probe_for_profiling>, HelpText<"Alias for --lto-pseudo-probe-for-profiling">;
 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">;

lld/test/ELF/lto/pseudo-probe-lto.ll

@@ -0,0 +1,36 @@
+; REQUIRES: x86
+; RUN: opt < %s -passes=pseudo-probe -function-sections -o %t.o
+; RUN: ld.lld %t.o -shared --lto-pseudo-probe-for-profiling --lto-emit-asm -o - | FileCheck %s
+; RUN: ld.lld %t.o -shared -plugin-opt=pseudo-probe-for-profiling --lto-emit-asm -o - | FileCheck %s
+
+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-scei-ps4"
+
+@g = dso_local global i32 3, align 4
+
+define void @foo(void (i32)* %f) !dbg !4 {
+entry:
+; CHECK: .pseudoprobe	[[#GUID:]] 1 0 0
+; CHECK: .pseudoprobe	[[#GUID]] 2 1 0
+  call void %f(i32 1), !dbg !13
+  %0 = load i32, i32* @g, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, i32* @g, align 4
+  ret void
+}
+
+; CHECK:      .section .pseudo_probe_desc,"G",@progbits,.pseudo_probe_desc_foo,comdat
+; CHECK-NEXT: .quad [[#GUID]]
+; CHECK-NEXT: .quad [[#HASH:]]
+; CHECK-NEXT: .byte  3
+; CHECK-NEXT: .ascii	"foo"
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!9, !10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1)
+!1 = !DIFile(filename: "test.c", directory: "")
+!4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, unit: !0)
+!9 = !{i32 2, !"Dwarf Version", i32 4}
+!10 = !{i32 2, !"Debug Info Version", i32 3}
+!13 = !DILocation(line: 2, column: 20, scope: !4)