[PATCH] D61058: [PPC64] Consider localentry offset when computing branch distance

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
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This fixes the spurious link error:

relocation R_PPC64_REL24 out of range: 33554436 is not in [-33554432, 33554431]


Repository:
  rLLD LLVM Linker

https://reviews.llvm.org/D61058

Files:
  ELF/Arch/PPC64.cpp
  test/ELF/ppc64-long-branch-localentry-offset.s


Index: test/ELF/ppc64-long-branch-localentry-offset.s
===================================================================
--- /dev/null
+++ test/ELF/ppc64-long-branch-localentry-offset.s
@@ -0,0 +1,29 @@
+# REQUIRES: ppc
+
+# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %s -o %t.o
+# RUN: ld.lld --no-toc-optimize %t.o -o %t
+# RUN: llvm-nm %t | FileCheck %s
+
+# CHECK-DAG: 0000000010010000 t __long_branch_callee
+# CHECK-DAG: 0000000010010010 T _start
+# CHECK-DAG: 0000000012010008 t callee
+
+# The bl instruction jumps to the local entry. The distance requires a long branch stub:
+# localentry(callee) - _start = 0x12010008+8 - 0x10010010 = 0x2000000
+
+# We used to compute globalentry(callee) - _start and caused a "R_PPC64_REL24
+# out of range" error because we didn't create the stub.
+
+.globl _start
+_start:
+  bl callee
+
+.space 0x1fffff4
+
+callee:
+.Lgep0:
+  addis 2, 12, .TOC.-.Lgep0 at ha
+  addi 2, 2, .TOC.-.Lgep0 at l
+.Llep0:
+  .localentry callee, .Llep0-.Lgep0
+  blr
Index: ELF/Arch/PPC64.cpp
===================================================================
--- ELF/Arch/PPC64.cpp
+++ ELF/Arch/PPC64.cpp
@@ -774,7 +774,10 @@
 
   // If the offset exceeds the range of the branch type then it will need
   // a range-extending thunk.
-  return !inBranchRange(Type, BranchAddr, S.getVA());
+  // See the comment in getRelocTargetVA() about R_PPC64_CALL.
+  return !inBranchRange(Type, BranchAddr,
+                        S.getVA() +
+                            getPPC64GlobalEntryToLocalEntryOffset(S.StOther));
 }
 
 bool PPC64::inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const {


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