Skip to content

Add function merger to be run during LTO link with gold plugin #121343

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
eleviant merged 2 commits into from
Jan 12, 2025
Merged

Add function merger to be run during LTO link with gold plugin #121343

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
7aa6aa1
All function merger to be run during LTO link with gold plugin
eleviant Dec 30, 2024
605fdd6
Merge branch 'main' into gold-plugin-merge-functions
eleviant Jan 12, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 25 additions & 0 deletions llvm/test/tools/gold/X86/Inputs/merge-functions-foo.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,25 @@
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"

@_g = dso_local global i32 0, align 4
@llvm.compiler.used = appending global [1 x ptr] [ptr @_g], section "llvm.metadata"

define dso_local i32 @foo(i32 noundef %0) #0 {
%2 = add nsw i32 %0, 42
store i32 %2, ptr @_g, align 4
ret i32 %2
}

attributes #0 = { noinline }

!llvm.module.flags = !{!0, !1}

!0 = !{i32 1, !"ThinLTO", i32 0}
!1 = !{i32 1, !"EnableSplitLTOUnit", i32 1}

^0 = module: (path: "/tmp/func2.o", hash: (0, 0, 0, 0, 0))
^1 = gv: (name: "foo", summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 1, live: 0, dsoLocal: 1, canAutoHide: 0), insts: 3, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 1, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), refs: (^3)))) ; guid = 6699318081062747564
^2 = gv: (name: "llvm.compiler.used", summaries: (variable: (module: ^0, flags: (linkage: appending, visibility: default, notEligibleToImport: 1, live: 1, dsoLocal: 0, canAutoHide: 0), varFlags: (readonly: 0, writeonly: 0, constant: 0), refs: (^3)))) ; guid = 9610627770985738006
^3 = gv: (name: "_g", summaries: (variable: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 1, live: 0, dsoLocal: 1, canAutoHide: 0), varFlags: (readonly: 1, writeonly: 1, constant: 0)))) ; guid = 9713702464056781075
^4 = flags: 8
^5 = blockcount: 0
49 changes: 49 additions & 0 deletions llvm/test/tools/gold/X86/merge-functions.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,49 @@
; RUN: llvm-as %s -o %t.bc
; RUN: llvm-as %p/Inputs/merge-functions-foo.ll -o %t-foo.bc
; RUN: %gold -plugin %llvmshlibdir/LLVMgold%shlibext \
; RUN: -m elf_x86_64 \
; RUN: -plugin-opt=merge-functions \
; RUN: -plugin-opt=save-temps \
; RUN: -u main \
; RUN: %t.bc %t-foo.bc \
; RUN: -o %t-out
; RUN: llvm-dis %t-out.0.5.precodegen.bc -o - | FileCheck %s

; Check that we've merged foo and bar
; CHECK: define dso_local noundef i32 @main()
; CHECK-NEXT: tail call fastcc void @bar()
; CHECK-NEXT: tail call fastcc void @bar()

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"

@_g = external local_unnamed_addr global i32, align 4

define dso_local i32 @bar(i32 noundef %0) #0 {
%2 = add nsw i32 %0, 42
store i32 %2, ptr @_g, align 4
ret i32 %2
}

define dso_local noundef i32 @main() {
%1 = tail call i32 @foo(i32 noundef 1)
%2 = tail call i32 @bar(i32 noundef 1)
ret i32 0
}

declare i32 @foo(i32 noundef) local_unnamed_addr #2

attributes #0 = { noinline }

!llvm.module.flags = !{!0, !1}

!0 = !{i32 1, !"ThinLTO", i32 0}
!1 = !{i32 1, !"EnableSplitLTOUnit", i32 1}

^0 = module: (path: "merge-functions.o", hash: (0, 0, 0, 0, 0))
^1 = gv: (name: "foo") ; guid = 6699318081062747564
^2 = gv: (name: "_g") ; guid = 9713702464056781075
^3 = gv: (name: "main", summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 1, live: 0, dsoLocal: 1, canAutoHide: 0), insts: 3, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 0, alwaysInline: 0, noUnwind: 1, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), calls: ((callee: ^1, tail: 1), (callee: ^4, tail: 1))))) ; guid = 15822663052811949562
^4 = gv: (name: "bar", summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 1, live: 0, dsoLocal: 1, canAutoHide: 0), insts: 3, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 1, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), refs: (^2)))) ; guid = 16434608426314478903
^5 = flags: 8
^6 = blockcount: 0
6 changes: 6 additions & 0 deletions llvm/tools/gold/gold-plugin.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -224,6 +224,9 @@ namespace options {
static std::string cs_profile_path;
static bool cs_pgo_gen = false;

// When true, MergeFunctions pass is used in LTO link pipeline.
static bool merge_functions = false;

// Time trace options.
static std::string time_trace_file;
static unsigned time_trace_granularity = 500;
Expand Down Expand Up @@ -292,6 +295,8 @@ namespace options {
sample_profile = std::string(opt);
} else if (opt == "cs-profile-generate") {
cs_pgo_gen = true;
} else if (opt == "merge-functions") {
merge_functions = true;
} else if (opt.consume_front("cs-profile-path=")) {
cs_profile_path = std::string(opt);
} else if (opt == "new-pass-manager") {
Expand Down Expand Up @@ -897,6 +902,7 @@ static std::unique_ptr<LTO> createLTO(IndexWriteCallback OnIndexWrite,
Conf.OptLevel = options::OptLevel;
Conf.PTO.LoopVectorization = options::OptLevel > 1;
Conf.PTO.SLPVectorization = options::OptLevel > 1;
Conf.PTO.MergeFunctions = options::merge_functions;
Conf.PTO.UnifiedLTO = options::unifiedlto;
Conf.AlwaysEmitRegularLTOObj = !options::obj_path.empty();

Expand Down
Loading