[lld] 2d077d6 - [ELF] Make TargetInfo::writeIgotPlt a no-op

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2020-01-10T09:59:22-08:00
New Revision: 2d077d6dfa7909a21293ebdac81488367628e0fa

URL: https://github.com/llvm/llvm-project/commit/2d077d6dfa7909a21293ebdac81488367628e0fa
DIFF: https://github.com/llvm/llvm-project/commit/2d077d6dfa7909a21293ebdac81488367628e0fa.diff

LOG: [ELF] Make TargetInfo::writeIgotPlt a no-op

RELA targets don't read initial .got.plt entries.
REL targets (ARM, x86-32) write the address of the IFUNC resolver to the
entry (`write32le(buf, s.getVA())`).

The default writeIgotPlt() is not meaningful. Make it a no-op. AArch64
and x86-64 will have 0 as initial .got.plt entries associated with
IFUNC.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D72474

Added: 
    

Modified: 
    lld/ELF/Target.cpp
    lld/ELF/Target.h
    lld/test/ELF/aarch64-gnu-ifunc-plt.s
    lld/test/ELF/gnu-ifunc-plt.s

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Target.cpp b/lld/ELF/Target.cpp
index aaae89bd087f..70a68fd8db9e 100644
--- a/lld/ELF/Target.cpp
+++ b/lld/ELF/Target.cpp
@@ -150,10 +150,6 @@ bool TargetInfo::inBranchRange(RelType type, uint64_t src, uint64_t dst) const {
   return true;
 }
 
-void TargetInfo::writeIgotPlt(uint8_t *buf, const Symbol &s) const {
-  writeGotPlt(buf, s);
-}
-
 RelExpr TargetInfo::adjustRelaxExpr(RelType type, const uint8_t *data,
                                     RelExpr expr) const {
   return expr;

diff  --git a/lld/ELF/Target.h b/lld/ELF/Target.h
index 7284bfd39b89..72067366b875 100644
--- a/lld/ELF/Target.h
+++ b/lld/ELF/Target.h
@@ -32,7 +32,7 @@ class TargetInfo {
   virtual void writeGotPltHeader(uint8_t *buf) const {}
   virtual void writeGotHeader(uint8_t *buf) const {}
   virtual void writeGotPlt(uint8_t *buf, const Symbol &s) const {};
-  virtual void writeIgotPlt(uint8_t *buf, const Symbol &s) const;
+  virtual void writeIgotPlt(uint8_t *buf, const Symbol &s) const {}
   virtual int64_t getImplicitAddend(const uint8_t *buf, RelType type) const;
   virtual int getTlsGdRelaxSkip(RelType type) const { return 1; }
 

diff  --git a/lld/test/ELF/aarch64-gnu-ifunc-plt.s b/lld/test/ELF/aarch64-gnu-ifunc-plt.s
index 08a6c4941450..91e812950d2f 100644
--- a/lld/test/ELF/aarch64-gnu-ifunc-plt.s
+++ b/lld/test/ELF/aarch64-gnu-ifunc-plt.s
@@ -23,8 +23,8 @@
 // GOTPLT: Contents of section .got.plt:
 // GOTPLT-NEXT:  230440 00000000 00000000 00000000 00000000
 // GOTPLT-NEXT:  230450 00000000 00000000 f0022100 00000000
-// GOTPLT-NEXT:  230460 f0022100 00000000 f0022100 00000000
-// GOTPLT-NEXT:  230470 f0022100 00000000
+// GOTPLT-NEXT:  230460 f0022100 00000000 00000000 00000000
+// GOTPLT-NEXT:  230470 00000000 00000000
 
 // Check that the PLTRELSZ tag does not include the IRELATIVE relocations
 // CHECK: DynamicSection [

diff  --git a/lld/test/ELF/gnu-ifunc-plt.s b/lld/test/ELF/gnu-ifunc-plt.s
index 2fad0b1de6b9..3d0cec038a9c 100644
--- a/lld/test/ELF/gnu-ifunc-plt.s
+++ b/lld/test/ELF/gnu-ifunc-plt.s
@@ -25,8 +25,8 @@
 // GOTPLT: Contents of section .got.plt:
 // GOTPLT-NEXT:  203430 40232000 00000000 00000000 00000000
 // GOTPLT-NEXT:  203440 00000000 00000000 06132000 00000000
-// GOTPLT-NEXT:  203450 16132000 00000000 26132000 00000000
-// GOTPLT-NEXT:  203460 36132000 00000000
+// GOTPLT-NEXT:  203450 16132000 00000000 00000000 00000000
+// GOTPLT-NEXT:  203460 00000000 00000000
 
 // Check that the PLTRELSZ tag does not include the IRELATIVE relocations
 // CHECK: DynamicSection [