[llvm] 2f34288 - Revert "[gold] Add preliminary FatLTO support to the Gold plugin"

Paul Kirth via llvm-commits llvm-commits at lists.llvm.org
Thu Jul 20 13:55:30 PDT 2023


Author: Paul Kirth
Date: 2023-07-20T20:53:08Z
New Revision: 2f34288b2476339e532a59fc43723b6de1a9ef08

URL: https://github.com/llvm/llvm-project/commit/2f34288b2476339e532a59fc43723b6de1a9ef08
DIFF: https://github.com/llvm/llvm-project/commit/2f34288b2476339e532a59fc43723b6de1a9ef08.diff

LOG: Revert "[gold] Add preliminary FatLTO support to the Gold plugin"

This reverts commit 421e4026111315d002879b1e7a0cf3aacd00f488.

One of the test needs a requires line, but we've also seen some issues
for downstream projects that may need coordination, so I'm reverting
this for until we can address those issues. see
https://reviews.llvm.org/D152973#4520240 for context.

Added: 
    

Modified: 
    llvm/lib/Object/ObjectFile.cpp
    llvm/test/LTO/X86/Inputs/bcsection.macho.s
    llvm/test/LTO/X86/bcsection.ll
    llvm/tools/gold/gold-plugin.cpp

Removed: 
    llvm/test/LTO/X86/Inputs/llvm.lto.section.s
    llvm/test/LTO/X86/llvm.lto.section.ll
    llvm/test/tools/gold/X86/fatlto/fatlto.invalid.s
    llvm/test/tools/gold/X86/fatlto/fatlto.test


################################################################################
diff  --git a/llvm/lib/Object/ObjectFile.cpp b/llvm/lib/Object/ObjectFile.cpp
index 2a672467f422dc..0820187f32e14c 100644
--- a/llvm/lib/Object/ObjectFile.cpp
+++ b/llvm/lib/Object/ObjectFile.cpp
@@ -79,7 +79,7 @@ uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
 bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
   Expected<StringRef> NameOrErr = getSectionName(Sec);
   if (NameOrErr)
-    return *NameOrErr == ".llvm.lto";
+    return *NameOrErr == ".llvmbc" || *NameOrErr == ".llvm.lto";
   consumeError(NameOrErr.takeError());
   return false;
 }

diff  --git a/llvm/test/LTO/X86/Inputs/bcsection.macho.s b/llvm/test/LTO/X86/Inputs/bcsection.macho.s
index 70e3b477102abe..24884b5a913659 100644
--- a/llvm/test/LTO/X86/Inputs/bcsection.macho.s
+++ b/llvm/test/LTO/X86/Inputs/bcsection.macho.s
@@ -2,4 +2,4 @@
 .asciz "Wrong Section"
 
 .section __LLVM,__bitcode
-.incbin "llvm.lto.section.bc"
+.incbin "bcsection.bc"

diff  --git a/llvm/test/LTO/X86/Inputs/llvm.lto.section.s b/llvm/test/LTO/X86/Inputs/llvm.lto.section.s
deleted file mode 100644
index 5457d0ffd6f963..00000000000000
--- a/llvm/test/LTO/X86/Inputs/llvm.lto.section.s
+++ /dev/null
@@ -1,2 +0,0 @@
-.section .llvm.lto
-.incbin "llvm.lto.section.bc"

diff  --git a/llvm/test/LTO/X86/bcsection.ll b/llvm/test/LTO/X86/bcsection.ll
index 673853f0a30217..1c7f3095480355 100644
--- a/llvm/test/LTO/X86/bcsection.ll
+++ b/llvm/test/LTO/X86/bcsection.ll
@@ -2,17 +2,23 @@
 ; RUN: llvm-as -o %t/bcsection.bc %s
 
 ; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-pc-win32 -o %t/bcsection.coff.bco %p/Inputs/bcsection.s
-; RUN: llvm-nm %t/bcsection.coff.bco | FileCheck %s --allow-empty
-; RUN: not llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.coff.o %t/bcsection.coff.bco
+; RUN: llvm-nm %t/bcsection.coff.bco | FileCheck %s
+; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.coff.o %t/bcsection.coff.bco
+; RUN: llvm-nm %t/bcsection.coff.o | FileCheck %s
 
 ; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-unknown-linux-gnu -o %t/bcsection.elf.bco %p/Inputs/bcsection.s
-; RUN: llvm-nm %t/bcsection.elf.bco | FileCheck %s --allow-empty
-; RUN: not llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.elf.o %t/bcsection.elf.bco
+; RUN: llvm-nm %t/bcsection.elf.bco | FileCheck %s
+; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.elf.o %t/bcsection.elf.bco
+; RUN: llvm-nm %t/bcsection.elf.o | FileCheck %s
+
+; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-apple-darwin11 -o %t/bcsection.macho.bco %p/Inputs/bcsection.macho.s
+; RUN: llvm-nm %t/bcsection.macho.bco | FileCheck %s
+; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.macho.o %t/bcsection.macho.bco
+; RUN: llvm-nm %t/bcsection.macho.o | FileCheck %s
 
 target triple = "x86_64-unknown-linux-gnu"
 
-;; The .llvmbc section is not intended for use with LTO, so there should be nothing here
-; CHECK-NOT: main
+; CHECK: main
 define i32 @main() {
   ret i32 0
 }

diff  --git a/llvm/test/LTO/X86/llvm.lto.section.ll b/llvm/test/LTO/X86/llvm.lto.section.ll
deleted file mode 100644
index 33d0bdb6e74527..00000000000000
--- a/llvm/test/LTO/X86/llvm.lto.section.ll
+++ /dev/null
@@ -1,25 +0,0 @@
-; RUN: rm -rf %t && mkdir -p %t
-; RUN: llvm-as -o %t/llvm.lto.section.bc %s
-
-; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-pc-win32 -o %t/llvm.lto.section.coff.bco %p/Inputs/llvm.lto.section.s
-; RUN: llvm-nm %t/llvm.lto.section.coff.bco | FileCheck %s
-; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/llvm.lto.section.coff.o %t/llvm.lto.section.coff.bco
-; RUN: llvm-nm %t/llvm.lto.section.coff.o | FileCheck %s
-
-; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-unknown-linux-gnu -o %t/llvm.lto.section.elf.bco %p/Inputs/llvm.lto.section.s
-; RUN: llvm-nm %t/llvm.lto.section.elf.bco | FileCheck %s
-; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/llvm.lto.section.elf.o %t/llvm.lto.section.elf.bco
-; RUN: llvm-nm %t/llvm.lto.section.elf.o | FileCheck %s
-
-
-; RUN: llvm-mc -I=%t -filetype=obj -triple=x86_64-apple-darwin11 -o %t/bcsection.macho.bco %p/Inputs/bcsection.macho.s
-; RUN: llvm-nm %t/bcsection.macho.bco | FileCheck %s
-; RUN: llvm-lto -exported-symbol=main -exported-symbol=_main -o %t/bcsection.macho.o %t/bcsection.macho.bco
-; RUN: llvm-nm %t/bcsection.macho.o | FileCheck %s
-
-target triple = "x86_64-unknown-linux-gnu"
-
-; CHECK: main
-define i32 @main() {
-  ret i32 0
-}

diff  --git a/llvm/test/tools/gold/X86/fatlto/fatlto.invalid.s b/llvm/test/tools/gold/X86/fatlto/fatlto.invalid.s
deleted file mode 100644
index 3a7116d8a2f7dc..00000000000000
--- a/llvm/test/tools/gold/X86/fatlto/fatlto.invalid.s
+++ /dev/null
@@ -1,9 +0,0 @@
-# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
-# RUN: not %gold -plugin %llvmshlibdir/LLVMgold%shlibext %t -o /dev/null 2>&1 | FileCheck %s
-
-# CHECK: error:{{.*}} Invalid bitcode signature
-
-.section        .llvm.lto,"e", at progbits
-.Lllvm.embedded.object:
-        .asciz  "BC\300\3365\000"
-        .size   .Lllvm.embedded.object, 12

diff  --git a/llvm/test/tools/gold/X86/fatlto/fatlto.test b/llvm/test/tools/gold/X86/fatlto/fatlto.test
deleted file mode 100644
index 5c8b15a498e033..00000000000000
--- a/llvm/test/tools/gold/X86/fatlto/fatlto.test
+++ /dev/null
@@ -1,108 +0,0 @@
-;; Basic FatLTO tests.
-
-; RUN: rm -rf %t && split-file %s %t
-
-;; Ensure that input files contain .llvm.lto section
-; RUN: llc %t/a-LTO.ll --filetype=obj -o %t/a-fatLTO.o
-; RUN: opt --module-summary %t/a-LTO.ll -o %t/a-fatLTO.bc
-; RUN: llvm-objcopy --add-section=.llvm.lto=%t/a-fatLTO.bc %t/a-fatLTO.o
-; RUN: llvm-objcopy --set-section-flags=.llvm.lto=readonly,exclude %t/a-fatLTO.o
-; RUN: llvm-readobj -S %t/a-fatLTO.o | FileCheck --check-prefix=CHECK-A %s
-
-; CHECK-A: Name: .llvm.lto
-
-; RUN: llc %t/main-LTO.ll --filetype=obj -o %t/main-fatLTO.o
-; RUN: opt --module-summary %t/main-LTO.ll -o %t/main-fatLTO.bc
-; RUN: llvm-objcopy --add-section=.llvm.lto=%t/main-fatLTO.bc %t/main-fatLTO.o
-; RUN: llvm-objcopy --set-section-flags=.llvm.lto=readonly,exclude %t/main-fatLTO.o
-; RUN: llvm-readobj -S %t/main-fatLTO.o | FileCheck --check-prefix=CHECK-MAIN %s
-
-; CHECK-MAIN: Name: .llvm.lto
-
-;; Final executable should not have .llvm.lto section no matter what the target is
-; RUN: %gold -plugin %llvmshlibdir/LLVMgold%shlibext -o %t/foo-fatLTO %t/a-fatLTO.o %t/main-fatLTO.o
-; RUN: llvm-readobj -S %t/foo-fatLTO | FileCheck --check-prefix=CHECK-LTO-TARGET %s
-
-;; Check that fat objects work w/ s=--start-lib
-; RUN: %gold -plugin %llvmshlibdir/LLVMgold%shlibext -o %t/foo-fatLTO.start_lib --start-lib %t/a-fatLTO.o %t/main-fatLTO.o --end-lib
-; RUN: llvm-readobj -S %t/foo-fatLTO.start_lib | FileCheck --check-prefix=CHECK-LTO-TARGET %s
-
-;; Check if .llvm.lto section gets aggregated in LTO target
-; CHECK-LTO-TARGET-NOT: Name: .llvm.lto
-
-;; Final executable should not have .llvm.lto section no matter what the target is
-; RUN: %gold -o %t/foo-fatNoLTO %t/a-fatLTO.o %/t/main-fatLTO.o
-; RUN: llvm-readobj -S %t/foo-fatNoLTO | FileCheck --check-prefix=CHECK-NON-LTO-TARGET %s
-
-;; Check if .llvm.lto section gets aggregated in non-LTO target
-; CHECK-NON-LTO-TARGET-NOT: Name: .llvm.lto
-
-;; Check if the LTO target executable produced from FatLTO object file is
-;; identical to the one produced from LTO modules
-; RUN: opt --module-summary %t/a-LTO.ll -o %t/a-LTO.bc
-; RUN: opt --module-summary %t/main-LTO.ll -o %t/main-LTO.bc
-; RUN: %gold -plugin %llvmshlibdir/LLVMgold%shlibext -o %t/foo-LTO %t/a-LTO.bc %t/main-LTO.bc
-; RUN: cmp %t/foo-fatLTO %t/foo-LTO
-
-;; Check if the no-LTO target executable produced from FatLTO object file is
-;; identical to the one produced from regular object files
-
-; RUN: llc %t/a-LTO.ll --filetype=obj -o %t/a.o
-; RUN: llc %t/main-LTO.ll --filetype=obj -o %t/main.o
-
-; RUN: %gold -o %t/foo-noLTO %t/a.o %t/main.o
-; RUN: cmp %t/foo-fatNoLTO %t/foo-noLTO
-
-;; Check archive support
-; RUN: llvm-ar rcs %t/a.a %t/a-fatLTO.o
-; RUN: %gold -plugin %llvmshlibdir/LLVMgold%shlibext -o %t/foo-fatLTO.archive %t/main-LTO.bc %t/a.a 
-; RUN: cmp %t/foo-fatLTO.archive %t/foo-LTO
-
-;--- a-LTO.ll
-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"
-
-; Function Attrs: noinline nounwind uwtable
-define dso_local i32 @_start() #0 {
-entry:
-  ret i32 0
-}
-
-attributes #0 = { noinline nounwind uwtable }
-
-!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
-
-!0 = !{i32 1, !"wchar_size", i32 4}
-!1 = !{i32 7, !"PIC Level", i32 2}
-!2 = !{i32 7, !"PIE Level", i32 2}
-!3 = !{i32 7, !"uwtable", i32 2}
-!4 = !{i32 7, !"frame-pointer", i32 2}
-!5 = !{i32 1, !"ThinLTO", i32 0}
-!6 = !{i32 1, !"EnableSplitLTOUnit", i32 1}
-
-;--- main-LTO.ll
-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"
-
-; Function Attrs: noinline nounwind uwtable
-define dso_local i32 @main() #0 {
-entry:
-  %retval = alloca i32, align 4
-  store i32 0, ptr %retval, align 4
-  %call = call i32 (...) @_start()
-  ret i32 %call
-}
-
-declare i32 @_start(...)
-
-attributes #0 = { noinline nounwind uwtable }
-
-!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6}
-
-!0 = !{i32 1, !"wchar_size", i32 4}
-!1 = !{i32 7, !"PIC Level", i32 2}
-!2 = !{i32 7, !"PIE Level", i32 2}
-!3 = !{i32 7, !"uwtable", i32 2}
-!4 = !{i32 7, !"frame-pointer", i32 2}
-!5 = !{i32 1, !"ThinLTO", i32 0}
-!6 = !{i32 1, !"EnableSplitLTOUnit", i32 1}

diff  --git a/llvm/tools/gold/gold-plugin.cpp b/llvm/tools/gold/gold-plugin.cpp
index 59bd3f6e668600..a47dba35aa472e 100644
--- a/llvm/tools/gold/gold-plugin.cpp
+++ b/llvm/tools/gold/gold-plugin.cpp
@@ -538,6 +538,14 @@ static ld_plugin_status claim_file_hook(const ld_plugin_input_file *file,
     BufferRef = Buffer->getMemBufferRef();
   }
 
+  // Only use bitcode files for LTO.  InputFile::create() will load bitcode
+  // from the .llvmbc section within a binary object, this bitcode is typically
+  // generated by -fembed-bitcode and is not to be used by LLVMgold.so for LTO.
+  if (identify_magic(BufferRef.getBuffer()) != file_magic::bitcode) {
+    *claimed = 0;
+    return LDPS_OK;
+  }
+
   *claimed = 1;
 
   Expected<std::unique_ptr<InputFile>> ObjOrErr = InputFile::create(BufferRef);


        


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