[lld] ad45df9 - [ELF][PPC64] Remove unneeded PPC64PCRelLongBranchThunk
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 30 11:33:21 PST 2021
Author: Fangrui Song
Date: 2021-11-30T11:33:17-08:00
New Revision: ad45df91ad6ad01234ded221d1cbdc168eaee53b
URL: https://github.com/llvm/llvm-project/commit/ad45df91ad6ad01234ded221d1cbdc168eaee53b
DIFF: https://github.com/llvm/llvm-project/commit/ad45df91ad6ad01234ded221d1cbdc168eaee53b.diff
LOG: [ELF][PPC64] Remove unneeded PPC64PCRelLongBranchThunk
This reverts the PPC64PCRelLongBranchThunk part from D86706.
PPC64PCRelLongBranchThunk is the same as PPC64R12SetupStub.
Use `__gep_setup_` instead of `__long_branch_pcrel_` for the stub symbol name
as it more closely indicates the operation.
(Note: GNU ld uses `*.long_branch.*` and `*.plt_branch.*`).
Reviewed By: NeHuang, nemanjai
Differential Revision: https://reviews.llvm.org/D114656
Added:
Modified:
lld/ELF/Thunks.cpp
lld/test/ELF/ppc64-pcrel-cross-link.s
lld/test/ELF/ppc64-pcrel-long-branch-error.s
lld/test/ELF/ppc64-pcrel-long-branch.s
Removed:
################################################################################
diff --git a/lld/ELF/Thunks.cpp b/lld/ELF/Thunks.cpp
index d548b847bb2fe..ffbc8d94a800e 100644
--- a/lld/ELF/Thunks.cpp
+++ b/lld/ELF/Thunks.cpp
@@ -399,24 +399,6 @@ class PPC64PDLongBranchThunk final : public PPC64LongBranchThunk {
}
};
-// A bl instruction uses a signed 24 bit offset, with an implicit 4 byte
-// alignment. This gives a possible 26 bits of 'reach'. If the caller and
-// callee do not use toc and the call offset is larger than 26 bits,
-// we need to emit a pc-rel based long-branch thunk. The target address of
-// the callee is computed with a PC-relative offset.
-class PPC64PCRelLongBranchThunk final : public Thunk {
-public:
- PPC64PCRelLongBranchThunk(Symbol &dest, int64_t addend)
- : Thunk(dest, addend) {
- alignment = 16;
- }
- uint32_t size() override { return 32; }
- void writeTo(uint8_t *buf) override;
- void addSymbols(ThunkSection &isec) override;
- bool isCompatibleWith(const InputSection &isec,
- const Relocation &rel) const override;
-};
-
} // end anonymous namespace
Defined *Thunk::addSymbol(StringRef name, uint8_t type, uint64_t value,
@@ -1061,42 +1043,6 @@ bool PPC64LongBranchThunk::isCompatibleWith(const InputSection &isec,
return rel.type == R_PPC64_REL24 || rel.type == R_PPC64_REL14;
}
-void PPC64PCRelLongBranchThunk::writeTo(uint8_t *buf) {
- int64_t offset = destination.getVA() - getThunkTargetSym()->getVA();
- if (!isInt<34>(offset))
- reportRangeError(buf, offset, 34, destination,
- "PC-relative long branch stub offset");
-
- int nextInstOffset;
- if (!config->power10Stubs) {
- uint32_t off = destination.getVA(addend) - getThunkTargetSym()->getVA() - 8;
- write32(buf + 0, 0x7c0802a6); // mflr r12
- write32(buf + 4, 0x429f0005); // bcl 20,31,.+4
- write32(buf + 8, 0x7d6802a6); // mflr r11
- write32(buf + 12, 0x7d8803a6); // mtlr r12
- write32(buf + 16, 0x3d8b0000 | computeHiBits(off)); // addis r12,r11,off at ha
- write32(buf + 20, 0x398c0000 | (off & 0xffff)); // addi r12,r12,off at l
- nextInstOffset = 24;
- } else {
- uint64_t paddi = PADDI_R12_NO_DISP | (((offset >> 16) & 0x3ffff) << 32) |
- (offset & 0xffff);
- writePrefixedInstruction(buf + 0, paddi); // paddi r12, 0, func at pcrel, 1
- nextInstOffset = 8;
- }
- write32(buf + nextInstOffset, MTCTR_R12); // mtctr r12
- write32(buf + nextInstOffset + 4, BCTR); // bctr
-}
-
-void PPC64PCRelLongBranchThunk::addSymbols(ThunkSection &isec) {
- addSymbol(saver.save("__long_branch_pcrel_" + destination.getName()),
- STT_FUNC, 0, isec);
-}
-
-bool PPC64PCRelLongBranchThunk::isCompatibleWith(const InputSection &isec,
- const Relocation &rel) const {
- return rel.type == R_PPC64_REL24_NOTOC;
-}
-
Thunk::Thunk(Symbol &d, int64_t a) : destination(d), addend(a), offset(0) {}
Thunk::~Thunk() = default;
@@ -1223,9 +1169,7 @@ static Thunk *addThunkPPC64(RelType type, Symbol &s, int64_t a) {
return make<PPC64R2SaveStub>(s, a);
if (type == R_PPC64_REL24_NOTOC)
- return (s.stOther >> 5) > 1
- ? (Thunk *)make<PPC64R12SetupStub>(s)
- : (Thunk *)make<PPC64PCRelLongBranchThunk>(s, a);
+ return make<PPC64R12SetupStub>(s);
if (config->picThunk)
return make<PPC64PILongBranchThunk>(s, a);
diff --git a/lld/test/ELF/ppc64-pcrel-cross-link.s b/lld/test/ELF/ppc64-pcrel-cross-link.s
index 620e113196bd9..c4c2c62575877 100644
--- a/lld/test/ELF/ppc64-pcrel-cross-link.s
+++ b/lld/test/ELF/ppc64-pcrel-cross-link.s
@@ -29,7 +29,7 @@
# NOSWAP-NEXT: blr
# NOSWAP-LABEL: 10030010 <__gep_setup_callee_toc>:
# NOSWAP: bctr
-# NOSWAP-LABEL: 10030030 <__long_branch_pcrel_callee_notoc>:
+# NOSWAP-LABEL: 10030030 <__gep_setup_callee_notoc>:
# NOSWAP: bctr
# NOSWAP-LABEL: 10040000 <caller_toc>:
# NOSWAP: bl 0x10040020
@@ -68,7 +68,7 @@
# SWAP-NEXT: blr
# SWAP-LABEL: 10040010 <__gep_setup_callee_toc>:
# SWAP: bctr
-# SWAP-LABEL: 10040030 <__long_branch_pcrel_callee_notoc>:
+# SWAP-LABEL: 10040030 <__gep_setup_callee_notoc>:
# SWAP: bctr
#--- lds
diff --git a/lld/test/ELF/ppc64-pcrel-long-branch-error.s b/lld/test/ELF/ppc64-pcrel-long-branch-error.s
index 00a1e7dd4d9ad..a572e69b95d05 100644
--- a/lld/test/ELF/ppc64-pcrel-long-branch-error.s
+++ b/lld/test/ELF/ppc64-pcrel-long-branch-error.s
@@ -18,7 +18,8 @@
# RUN: ld.lld -shared --script %t/lds %t.o -o %t1 --noinhibit-exec
# RUN: rm %t.o %t1
-# CHECK: error: PC-relative long branch stub offset is out of range: 8589934592 is not in [-8589934592, 8589934591]; references high
+## Note: GNU ld uses sldi 11, 11, 34 and add 12, 11, 12 to support offsets beyond +-2**33.
+# CHECK: error: R12 setup stub offset is out of range: 8589934592 is not in [-8589934592, 8589934591]; references high
# CHECK-NEXT: >>> defined in {{.*}}.o
//--- asm
diff --git a/lld/test/ELF/ppc64-pcrel-long-branch.s b/lld/test/ELF/ppc64-pcrel-long-branch.s
index 68ec7b537b473..88e2b455ed76a 100644
--- a/lld/test/ELF/ppc64-pcrel-long-branch.s
+++ b/lld/test/ELF/ppc64-pcrel-long-branch.s
@@ -27,7 +27,7 @@
# CHECK-NEXT: trap
## Callee address - program counter = 0x2002000 - 0x2010 = 33554416
-# CHECK-LABEL: <__long_branch_pcrel_high>:
+# CHECK-LABEL: <__gep_setup_high>:
# CHECK-NEXT: 2010: paddi 12, 0, 33554416, 1
# CHECK-NEXT: mtctr 12
# CHECK-NEXT: bctr
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