[llvm] 853a264 - [AsmPrinter] __patchable_function_entries: Set SHF_LINK_ORDER for binutils 2.36 and above

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2021-02-05T19:53:06-08:00
New Revision: 853a2649160c1c80b9bbd38a20b53ca8fab704e8

URL: https://github.com/llvm/llvm-project/commit/853a2649160c1c80b9bbd38a20b53ca8fab704e8
DIFF: https://github.com/llvm/llvm-project/commit/853a2649160c1c80b9bbd38a20b53ca8fab704e8.diff

LOG: [AsmPrinter] __patchable_function_entries: Set SHF_LINK_ORDER for binutils 2.36 and above

This matches GCC behavior when the configure-time binutils is new. GNU ld<2.36
did not support mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER sections in an
output section, so we conservatively disable SHF_LINK_ORDER for <2.36.

Added: 
    

Modified: 
    llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
    llvm/test/CodeGen/AArch64/patchable-function-entry.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index b6f100984492..c2e2a4f7695d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -3464,9 +3464,9 @@ void AsmPrinter::emitPatchableFunctionEntries() {
     const MCSymbolELF *LinkedToSym = nullptr;
     StringRef GroupName;
 
-    // GNU as < 2.35 did not support section flag 'o'. Use SHF_LINK_ORDER only
-    // if we are using the integrated assembler.
-    if (MAI->useIntegratedAssembler()) {
+    // GNU as < 2.35 did not support section flag 'o'. GNU ld < 2.36 did not
+    // support mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER sections.
+    if (MAI->useIntegratedAssembler() || MAI->binutilsIsAtLeast(2, 36)) {
       Flags |= ELF::SHF_LINK_ORDER;
       if (F.hasComdat()) {
         Flags |= ELF::SHF_GROUP;

diff  --git a/llvm/test/CodeGen/AArch64/patchable-function-entry.ll b/llvm/test/CodeGen/AArch64/patchable-function-entry.ll
index 2d5615678d8c..776890639ec6 100644
--- a/llvm/test/CodeGen/AArch64/patchable-function-entry.ll
+++ b/llvm/test/CodeGen/AArch64/patchable-function-entry.ll
@@ -1,8 +1,10 @@
 ; RUN: llc -mtriple=aarch64 %s -o - | FileCheck %s
 ; RUN: llc -mtriple=aarch64 -function-sections %s -o - | FileCheck %s
-; RUN: llc -mtriple=aarch64 -no-integrated-as %s -o - | FileCheck --check-prefix=NOLINK %s
+; RUN: llc -mtriple=aarch64 -function-sections %s -o - | FileCheck %s
+; RUN: llc -mtriple=aarch64 -no-integrated-as -binutils-version=2.35 %s -o - | FileCheck --check-prefix=NOLINK %s
+; RUN: llc -mtriple=aarch64 -no-integrated-as -binutils-version=2.36 %s -o - | FileCheck %s
 
-;; GNU as < 2.35 did not support section flag 'o'.
+;; GNU ld < 2.36 did not support mixed SHF_LINK_ORDER and non-SHF_LINK_ORDER sections.
 ; NOLINK-NOT: "awo"
 
 define i32 @f0() "patchable-function-entry"="0" {