[lld] [ELF] Respect ltoCanOmit for symbols in non-prevailing COMDAT (PR #119332)

Fangrui Song via llvm-commits llvm-commits at lists.llvm.org
Tue Dec 10 09:29:07 PST 2024


https://github.com/MaskRay updated https://github.com/llvm/llvm-project/pull/119332

>From b1038ce4435ca7808b3ebed5c4db33b7d4fd0acf Mon Sep 17 00:00:00 2001
From: Fangrui Song <i at maskray.me>
Date: Mon, 9 Dec 2024 22:42:33 -0800
Subject: [PATCH] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20initia?=
 =?UTF-8?q?l=20version?=
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Created using spr 1.3.5-bogner
---
 lld/ELF/InputFiles.cpp                        |  8 ++-
 .../ELF/lto/Inputs/internalize-exportdyn.ll   | 25 +++++++++
 lld/test/ELF/lto/internalize-exportdyn.ll     | 54 ++++++++++++++++---
 3 files changed, 76 insertions(+), 11 deletions(-)

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 2084fcfd4d651a..c44773d0b7dabe 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -1709,7 +1709,6 @@ static uint8_t mapVisibility(GlobalValue::VisibilityTypes gvVisibility) {
 }
 
 static void createBitcodeSymbol(Ctx &ctx, Symbol *&sym,
-                                const std::vector<bool> &keptComdats,
                                 const lto::InputFile::Symbol &objSym,
                                 BitcodeFile &f) {
   uint8_t binding = objSym.isWeak() ? STB_WEAK : STB_GLOBAL;
@@ -1726,8 +1725,7 @@ static void createBitcodeSymbol(Ctx &ctx, Symbol *&sym,
     sym = ctx.symtab->insert(objSym.getName());
   }
 
-  int c = objSym.getComdatIndex();
-  if (objSym.isUndefined() || (c != -1 && !keptComdats[c])) {
+  if (objSym.isUndefined()) {
     Undefined newSym(&f, StringRef(), binding, visibility, type);
     sym->resolve(ctx, newSym);
     sym->referenced = true;
@@ -1766,10 +1764,10 @@ void BitcodeFile::parse() {
   // ObjFile<ELFT>::initializeSymbols.
   for (auto [i, irSym] : llvm::enumerate(obj->symbols()))
     if (!irSym.isUndefined())
-      createBitcodeSymbol(ctx, symbols[i], keptComdats, irSym, *this);
+      createBitcodeSymbol(ctx, symbols[i], irSym, *this);
   for (auto [i, irSym] : llvm::enumerate(obj->symbols()))
     if (irSym.isUndefined())
-      createBitcodeSymbol(ctx, symbols[i], keptComdats, irSym, *this);
+      createBitcodeSymbol(ctx, symbols[i], irSym, *this);
 
   for (auto l : obj->getDependentLibraries())
     addDependentLibrary(ctx, l, this);
diff --git a/lld/test/ELF/lto/Inputs/internalize-exportdyn.ll b/lld/test/ELF/lto/Inputs/internalize-exportdyn.ll
index 585b99ae5a513a..5bfe15c92b3f18 100644
--- a/lld/test/ELF/lto/Inputs/internalize-exportdyn.ll
+++ b/lld/test/ELF/lto/Inputs/internalize-exportdyn.ll
@@ -1,6 +1,31 @@
 target triple = "x86_64-unknown-linux-gnu"
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 
+$ext_and_ext = comdat any
+$lo_and_ext = comdat any
+$lo_and_wo = comdat any
+$wo_and_lo = comdat any
+
+declare void @foo(i64)
+
 define weak_odr void @bah() {
   ret void
 }
+
+define void @ext_and_ext() local_unnamed_addr comdat {
+  call void @foo(i64 2)
+  ret void
+}
+
+define linkonce_odr void @lo_and_ext() local_unnamed_addr comdat {
+  call void @foo(i64 2)
+  ret void
+}
+
+define weak_odr void @lo_and_wo() local_unnamed_addr comdat {
+  ret void
+}
+
+define linkonce_odr void @wo_and_lo() local_unnamed_addr comdat {
+  ret void
+}
diff --git a/lld/test/ELF/lto/internalize-exportdyn.ll b/lld/test/ELF/lto/internalize-exportdyn.ll
index f02d3b375dad50..da3bf8e884505b 100644
--- a/lld/test/ELF/lto/internalize-exportdyn.ll
+++ b/lld/test/ELF/lto/internalize-exportdyn.ll
@@ -1,14 +1,22 @@
 ; REQUIRES: x86
-; RUN: llvm-as %s -o %t.o
-; RUN: llvm-as %p/Inputs/internalize-exportdyn.ll -o %t2.o
-; RUN: ld.lld %t.o %t2.o -o %t2 --export-dynamic -save-temps
-; RUN: llvm-dis < %t2.0.2.internalize.bc | FileCheck %s
-; RUN: ld.lld %t.o %t2.o -o %t3 -shared -save-temps
-; RUN: llvm-dis < %t3.0.2.internalize.bc | FileCheck %s --check-prefix=DSO
+; RUN: rm -rf %t && split-file %s %t && cd %t
+; RUN: llvm-as a.ll -o a.bc
+; RUN: llvm-as %p/Inputs/internalize-exportdyn.ll -o b.bc
+; RUN: llvm-mc -filetype=obj -triple=x86_64 lib.s -o lib.o
+; RUN: ld.lld a.bc b.bc lib.o -o out --export-dynamic -save-temps
+; RUN: llvm-dis < out.0.2.internalize.bc | FileCheck %s
+; RUN: ld.lld a.bc b.bc lib.o -o out2 -shared -save-temps
+; RUN: llvm-dis < out2.0.2.internalize.bc | FileCheck %s --check-prefix=DSO
 
+;--- a.ll
 target triple = "x86_64-unknown-linux-gnu"
 target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
 
+$ext_and_ext = comdat any
+$lo_and_ext = comdat any
+$lo_and_wo = comdat any
+$wo_and_lo = comdat any
+
 @c = linkonce_odr constant i32 1
 @g = linkonce_odr global i32 1
 @u_c = linkonce_odr unnamed_addr constant i32 1
@@ -16,6 +24,8 @@ target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16
 @lu_c = linkonce_odr local_unnamed_addr constant i32 1
 @lu_g = linkonce_odr local_unnamed_addr global i32 1
 
+declare void @lib(i64)
+
 define void @_start() {
   ret void
 }
@@ -46,6 +56,24 @@ define linkonce_odr void @baz() {
 
 @use_baz = global ptr @baz
 
+define void @ext_and_ext() local_unnamed_addr comdat {
+  call void @foo(i64 1)
+  ret void
+}
+
+define linkonce_odr void @lo_and_ext() local_unnamed_addr comdat {
+  call void @foo(i64 1)
+  ret void
+}
+
+define linkonce_odr void @lo_and_wo() local_unnamed_addr comdat {
+  ret void
+}
+
+define weak_odr void @wo_and_lo() local_unnamed_addr comdat {
+  ret void
+}
+
 ; Check what gets internalized.
 ; CHECK: @c = weak_odr dso_local constant i32 1
 ; CHECK: @g = weak_odr dso_local global i32 1
@@ -60,6 +88,12 @@ define linkonce_odr void @baz() {
 ; CHECK: define internal void @zed2()
 ; CHECK: define weak_odr dso_local void @bah()
 ; CHECK: define weak_odr dso_local void @baz()
+; CHECK: define dso_local void @ext_and_ext() comdat
+; CHECK-NEXT: call void @foo(i64 1)
+; CHECK: define internal void @lo_and_ext() comdat
+; CHECK-NEXT: call void @foo(i64 1)
+; CHECK: define weak_odr dso_local void @lo_and_wo() comdat
+; CHECK: define weak_odr dso_local void @wo_and_lo() comdat
 
 ; DSO: @c = weak_odr constant i32 1
 ; DSO: @g = weak_odr global i32 1
@@ -74,3 +108,11 @@ define linkonce_odr void @baz() {
 ; DSO: define internal void @zed2()
 ; DSO: define weak_odr void @bah()
 ; DSO: define weak_odr void @baz()
+; DSO: define void @ext_and_ext() comdat
+; DSO: define internal void @lo_and_ext() comdat
+; DSO: define weak_odr void @lo_and_wo() comdat
+; DSO: define weak_odr void @wo_and_lo() comdat
+
+;--- lib.s
+.globl lib
+lib:



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