Index: ELF/Arch/PPC64.cpp
===================================================================
--- ELF/Arch/PPC64.cpp
+++ ELF/Arch/PPC64.cpp
@@ -47,6 +47,8 @@
int32_t Index, unsigned RelOff) const override;
void relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const override;
void writeGotHeader(uint8_t *Buf) const override;
+ bool needsThunk(RelExpr Expr, RelType Type, const InputFile *File,
+ uint64_t BranchAddr, const Symbol &S) const override;
};
} // namespace
@@ -64,6 +66,7 @@
PPC64::PPC64() {
GotRel = R_PPC64_GLOB_DAT;
+ PltRel = R_PPC64_JMP_SLOT;
RelativeRel = R_PPC64_RELATIVE;
GotEntrySize = 8;
GotPltEntrySize = 8;
@@ -71,10 +74,9 @@
PltHeaderSize = 0;
GotBaseSymInGotPlt = false;
GotBaseSymOff = 0x8000;
-
GotHeaderEntriesNum = 1;
GotPltHeaderEntriesNum = 2;
- PltRel = R_PPC64_JMP_SLOT;
+ NeedsThunks = true;
// We need 64K pages (at least under glibc/Linux, the loader won't
// set different permissions on a finer granularity than that).
@@ -274,6 +276,13 @@
}
}
+bool PPC64::needsThunk(RelExpr Expr, RelType Type, const InputFile *File,
+ uint64_t BranchAddr, const Symbol &S) const {
+ // If a function is in the plt it needs to be called through
+ // a call stub.
+ return Type == R_PPC64_REL24 && S.isInPlt();
+}
+
TargetInfo *elf::getPPC64TargetInfo() {
static PPC64 Target;
return &Target;
Index: ELF/InputSection.cpp
===================================================================
--- ELF/InputSection.cpp
+++ ELF/InputSection.cpp
@@ -740,13 +740,15 @@
case R_RELAX_TLS_GD_TO_IE_END:
Target->relaxTlsGdToIe(BufLoc, Type, TargetVA);
break;
- case R_PPC_CALL_PLT:
+ case R_PPC_CALL:
// Patch a nop (0x60000000) to a ld.
- if (BufLoc + 8 > BufEnd || read32(BufLoc + 4) != 0x60000000) {
- error(getErrorLocation(BufLoc) + "call lacks nop, can't restore toc");
- break;
+ if (Rel.Sym->NeedsTocRestore) {
+ if (BufLoc + 8 > BufEnd || read32(BufLoc + 4) != 0x60000000) {
+ error(getErrorLocation(BufLoc) + "call lacks nop, can't restore toc");
+ break;
+ }
+ write32(BufLoc + 4, 0xe8410018); // ld %r2, 24(%r1)
}
- write32(BufLoc + 4, 0xe8410018); // ld %r2, 24(%r1)
Target->relocateOne(BufLoc, Type, TargetVA);
break;
default:
Index: ELF/Symbols.h
===================================================================
--- ELF/Symbols.h
+++ ELF/Symbols.h
@@ -159,7 +159,8 @@
: File(File), NameData(Name.Data), NameSize(Name.Size), Binding(Binding),
Type(Type), StOther(StOther), SymbolKind(K), NeedsPltAddr(false),
IsInGlobalMipsGot(false), Is32BitMipsGot(false), IsInIplt(false),
- IsInIgot(false), IsPreemptible(false), Used(!Config->GcSections) {}
+ IsInIgot(false), IsPreemptible(false), Used(!Config->GcSections),
+ NeedsTocRestore(false) {}
public:
// True the symbol should point to its PLT entry.
@@ -183,6 +184,10 @@
// True if an undefined or shared symbol is used from a live section.
unsigned Used : 1;
+ // True if a call to this symbol needs to be followed by a restore of the
+ // PPC64 toc pointer.
+ unsigned NeedsTocRestore : 1;
+
// The Type field may also have this value. It means that we have not yet seen
// a non-Lazy symbol with this name, so we don't know what its type is. The
// Type field is normally set to this value for Lazy symbols unless we saw a
Index: ELF/Thunks.cpp
===================================================================
--- ELF/Thunks.cpp
+++ ELF/Thunks.cpp
@@ -192,6 +192,23 @@
InputSection *getTargetInputSection() const override;
};
+
+// PPC64 Plt call stubs.
+// Any call site that needs to call through a plt entry needs a call stub in
+// the .text section. The call stub is responsible for:
+// 1) Saving the toc-pointer to the stack.
+// 2) Loading the target functions address from the procedure linkage table into
+// r12 for use by the target functions global entry point, and into the count
+// register.
+// 3) Transfering control to the target function through an indirect branch.
+class PPC64PltCallStub final : public Thunk {
+public:
+ PPC64PltCallStub(Symbol &Dest) : Thunk(Dest) {}
+ uint32_t size() { return 20; }
+ void writeTo(uint8_t *Buf) override;
+ void addSymbols(ThunkSection &IS) override;
+};
+
} // end anonymous namespace
Defined *Thunk::addSymbol(StringRef Name, uint8_t Type, uint64_t Value,
@@ -485,6 +502,25 @@
return dyn_cast<InputSection>(DR.Section);
}
+void PPC64PltCallStub::writeTo(uint8_t *Buf) {
+ int64_t Off = Destination.getGotPltVA() - getPPC64TocBase();
+ // Need to add 0x8000 to offset to account for the low bits being signed.
+ uint16_t OffHa = (Off + 0x8000) >> 16;
+ uint16_t OffLo = (uint16_t)Off;
+
+ write32(Buf + 0, 0xf8410018); // std r2,24(r1)
+ write32(Buf + 4, 0x3d820000 | OffHa); // addis r12,r2, X@plt@to@ha
+ write32(Buf + 8, 0xe98c0000 | OffLo); // ld r12,X@plt@toc@l(r12)
+ write32(Buf + 12, 0x7d8903a6); // mtctr r12
+ write32(Buf + 16, 0x4e800420); // bctr
+}
+
+void PPC64PltCallStub::addSymbols(ThunkSection &IS) {
+ Defined *S = addSymbol(Saver.save("__plt_" + Destination.getName()), STT_FUNC,
+ 0, IS);
+ S->NeedsTocRestore = true;
+}
+
Thunk::Thunk(Symbol &D) : Destination(D), Offset(0) {}
Thunk::~Thunk() = default;
@@ -528,14 +564,26 @@
return make<MipsThunk>(S);
}
+static Thunk *addThunkPPC64(RelType Type, Symbol &S) {
+ if (Type == R_PPC64_REL24)
+ return make<PPC64PltCallStub>(S);
+ fatal("unexpected relocation type");
+}
+
Thunk *addThunk(RelType Type, Symbol &S) {
if (Config->EMachine == EM_AARCH64)
return addThunkAArch64(Type, S);
- else if (Config->EMachine == EM_ARM)
+
+ if (Config->EMachine == EM_ARM)
return addThunkArm(Type, S);
- else if (Config->EMachine == EM_MIPS)
+
+ if (Config->EMachine == EM_MIPS)
return addThunkMips(Type, S);
- llvm_unreachable("add Thunk only supported for ARM and Mips");
+
+ if (Config->EMachine == EM_PPC64)
+ return addThunkPPC64(Type, S);
+
+ llvm_unreachable("add Thunk only supported for ARM, Mips and PowerPC");
return nullptr;
}
Index: test/ELF/ppc64-ifunc.s
===================================================================
--- test/ELF/ppc64-ifunc.s
+++ test/ELF/ppc64-ifunc.s
@@ -4,37 +4,57 @@
# RUN: llvm-mc -filetype=obj -triple=powerpc64le-unknown-linux %p/Inputs/shared-ppc64.s -o %t2.o
# RUN: ld.lld -shared %t2.o -o %t2.so
# RUN: ld.lld %t.o %t2.so -o %t
-# RUN: llvm-objdump -d %t | FileCheck %s
+# RUN: llvm-objdump -D %t | FileCheck %s
# RUN: llvm-mc -filetype=obj -triple=powerpc64-unknown-linux %s -o %t.o
# RUN: llvm-mc -filetype=obj -triple=powerpc64-unknown-linux %p/Inputs/shared-ppc64.s -o %t2.o
# RUN: ld.lld -shared %t2.o -o %t2.so
# RUN: ld.lld %t.o %t2.so -o %t
-# RUN: llvm-objdump -d %t | FileCheck %s
-
-# CHECK: _start:
-# CHECK-NEXT: 10010004: {{.*}} bl .+28
-# CHECK-NEXT: 10010008: {{.*}} ld 2, 24(1)
-# CHECK-NEXT: 1001000c: {{.*}} bl .+52
-# CHECK-NEXT: 10010010: {{.*}} ld 2, 24(1)
-
-# 0x10010004 + 28 = 0x10010020 (PLT entry 0)
-# 0x1001000c + 52 = 0x10010040 (PLT entry 1)
-
-# CHECK: Disassembly of section .plt:
-# CHECK-NEXT: .plt:
-# CHECK-NEXT: 10010020: {{.*}} std 2, 24(1)
-# CHECK-NEXT: 10010024: {{.*}} addis 12, 2, 4098
-# CHECK-NEXT: 10010028: {{.*}} ld 12, -32752(12)
-# CHECK-NEXT: 1001002c: {{.*}} mtctr 12
-# CHECK-NEXT: 10010030: {{.*}} bctr
-# CHECK-NEXT: 10010034: {{.*}} trap
-# CHECK-NEXT: 10010038: {{.*}} trap
-# CHECK-NEXT: 1001003c: {{.*}} trap
-# CHECK-NEXT: 10010040: {{.*}} std 2, 24(1)
-# CHECK-NEXT: 10010044: {{.*}} addis 12, 2, 4098
-# CHECK-NEXT: 10010048: {{.*}} ld 12, -32744(12)
-# CHECK-NEXT: 1001004c: {{.*}} mtctr 12
+# RUN: llvm-objdump -D %t | FileCheck %s
+
+# CHECK: Disassembly of section .text:
+
+# Tocbase + (-2 << 16) + 32576
+# 0x100380d0 + (-131072) + 32576 = 0x10020010 (.got.plt[2])
+# CHECK: __plt_foo:
+# CHECK-NEXT: std 2, 24(1)
+# CHECK-NEXT: addis 12, 2, -2
+# CHECK-NEXT: ld 12, 32576(12)
+# CHECK-NEXT: mtctr 12
+# CHECK-NEXT: bctr
+
+# Tocbase + (-2 << 16) + 32584
+# 0x100380d0 + (-131072) + 32584 = 0x10020018 (.got.plt[3])
+# CHECK: __plt_ifunc:
+# CHECK-NEXT: std 2, 24(1)
+# CHECK-NEXT: addis 12, 2, -2
+# CHECK-NEXT: ld 12, 32584(12)
+# CHECK-NEXT: mtctr 12
+# CHECK-NEXT: bctr
+
+# CHECK: ifunc:
+# CHECK-NEXT: 10010028: {{.*}} nop
+
+# CHECK: _start:
+# CHECK-NEXT: addis 2, 12, 3
+# CHECK-NEXT: addi 2, 2, -32604
+# CHECK-NEXT: bl .+67108812
+# CHECK-NEXT: ld 2, 24(1)
+# CHECK-NEXT: bl .+67108824
+# CHECK-NEXT: ld 2, 24(1)
+
+# Address of .got.plt
+# CHECK: Disassembly of section .got.plt:
+# CHECK-NEXT: .got.plt:
+# CHECK-NEXT: 10020000:
+
+
+# Check tocbase
+# CHECK: Disassembly of section .got:
+# CHECK-NEXT: .got:
+# CHECK-NEXT: 100300d0:
+
+
.text
.abiversion 2
@@ -43,8 +63,15 @@
ifunc:
nop
-.global _start
+ .global _start
+ .type _start,@function
+
_start:
+.Lfunc_gep0:
+ addis 2, 12, .TOC.-.Lfunc_gep0@ha
+ addi 2, 2, .TOC.-.Lfunc_gep0@l
+.Lfunc_lep0:
+ .localentry _start, .Lfunc_lep0-.Lfunc_gep0
bl foo
nop
bl ifunc
Index: test/ELF/ppc64-plt-stub.s
===================================================================
--- test/ELF/ppc64-plt-stub.s
+++ test/ELF/ppc64-plt-stub.s
@@ -12,9 +12,17 @@
// RUN: ld.lld %t.o %t2.so -o %t
// RUN: llvm-objdump -d %t | FileCheck %s
-// CHECK: Disassembly of section .text:
+// CHECK: Disassembly of section .text:
+// CHECK-NEXT: __plt_foo:
+// CHECK-NEXT: std 2, 24(1)
+// CHECK-NEXT: addis 12, 2, -2
+// CHECK-NEXT: ld 12, 32576(12)
+// CHECK-NEXT: mtctr 12
+// CHECK-NEXT: bctr
+
+
// CHECK: _start:
-// CHECK: bl .+24
+// CHECK: bl .+67108824
.text
.abiversion 2
.globl _start
@@ -32,13 +40,3 @@
li 0, 1
sc
.size _start, .-.Lfunc_begin0
-
-
-
-// CHECK: Disassembly of section .plt:
-// CHECK: .plt:
-// CHECK-NEXT: {{.*}} std 2, 24(1)
-// CHECK-NEXT: {{.*}} addis 12, 2, -2
-// CHECK-NEXT: {{.*}} ld 12, 32576(12)
-// CHECK-NEXT: {{.*}} mtctr 12
-// CHECK: {{.*}} bctr
Index: test/ELF/ppc64-toc-restore.s
===================================================================
--- test/ELF/ppc64-toc-restore.s
+++ test/ELF/ppc64-toc-restore.s
@@ -23,20 +23,21 @@
# Calling external function foo in a shared object needs a nop.
# Calling local function bar_local doe snot need a nop.
-// CHECK: Disassembly of section .text:
.global _start
_start:
bl foo
nop
bl bar_local
+
+// CHECK: Disassembly of section .text:
// CHECK: _start:
-// CHECK: 10010008: {{.*}} bl .+72
-// CHECK-NOT: 1001000c: {{.*}} nop
-// CHECK: 1001000c: {{.*}} ld 2, 24(1)
-// CHECK: 10010010: {{.*}} bl .+67108848
-// CHECK-NOT: 10010014: {{.*}} nop
-// CHECK-NOT: 10010014: {{.*}} ld 2, 24(1)
+// CHECK: 1001001c: {{.*}} bl .+67108836
+// CHECK-NOT: 10010020: {{.*}} nop
+// CHECK: 10010020: {{.*}} ld 2, 24(1)
+// CHECK: 10010024: {{.*}} bl .+67108848
+// CHECK-NOT: 10010028: {{.*}} nop
+// CHECK-NOT: 10010028: {{.*}} ld 2, 24(1)
# Calling a function in another object file which will have same
# TOC base does not need a nop. If nop present, do not rewrite to
@@ -48,18 +49,18 @@
nop
// CHECK: _diff_object:
-// CHECK-NEXT: 10010014: {{.*}} bl .+28
-// CHECK-NEXT: 10010018: {{.*}} bl .+24
-// CHECK-NEXT: 1001001c: {{.*}} nop
+// CHECK-NEXT: 10010028: {{.*}} bl .+24
+// CHECK-NEXT: 1001002c: {{.*}} bl .+20
+// CHECK-NEXT: 10010030: {{.*}} nop
# Branching to a local function does not need a nop
.global noretbranch
noretbranch:
b bar_local
// CHECK: noretbranch:
-// CHECK: 10010020: {{.*}} b .+67108832
-// CHECK-NOT: 10010024: {{.*}} nop
-// CHECK-NOT: 10010024: {{.*}} ld 2, 24(1)
+// CHECK: 10010034: {{.*}} b .+67108832
+// CHECK-NOT: 10010038: {{.*}} nop
+// CHECK-NOT: 1001003c: {{.*}} ld 2, 24(1)
// This should come last to check the end-of-buffer condition.
.global last
@@ -67,12 +68,5 @@
bl foo
nop
// CHECK: last:
-// CHECK: 10010024: {{.*}} bl .+44
-// CHECK-NEXT: 10010028: {{.*}} ld 2, 24(1)
-
-// CHECK: Disassembly of section .plt:
-// CHECK: .plt:
-// CHECK-NEXT: 10010050: {{.*}} std 2, 24(1)
-// CHECK-NEXT: 10010054: {{.*}} addis 12, 2, 4098
-// CHECK-NEXT: 10010058: {{.*}} ld 12, -32752(12)
-// CHECK-NEXT: 1001005c: {{.*}} mtctr 12
+// CHECK: 10010038: {{.*}} bl .+67108808
+// CHECK-NEXT: 1001003c: {{.*}} ld 2, 24(1)