From 656afe370df3ac374db7624e0b450f15a2212ab2 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Wed, 29 May 2019 02:02:59 +0000 Subject: [PATCH] [X86] Fix x86-64 call *foo@tlsdesc(%rax) and support R_386_TLSGOTDESC R_386_TLS_DESC_CALL D18885 emitted 5 bytes for call *foo@tlsdesc(%rax). It should use the 2-byte form instead and let R_X86_64_TLSDESC_CALL apply to the beginning of the call instruction. The 2-byte form was deliberately chosen to make ->LE and ->IE relaxation work: 0: 48 8d 05 00 00 00 00 lea 0x0(%rip),%rax # 7 <.text+0x7> 3: R_X86_64_GOTPC32_TLSDESC a-0x4 7: ff 10 callq *(%rax) 7: R_X86_64_TLSDESC_CALL a => 0: 48 c7 c0 fc ff ff ff mov $0xfffffffffffffffc,%rax 7: 66 90 xchg %ax,%ax Also change the symbol type to STT_TLS when VK_TLSCALL or VK_TLSDESC is seen. Reviewed By: compnerd Differential Revision: https://reviews.llvm.org/D62512 llvm-svn: 361910 --- llvm/lib/MC/MCELFStreamer.cpp | 2 ++ .../X86/MCTargetDesc/X86ELFObjectWriter.cpp | 4 +++ .../X86/MCTargetDesc/X86MCCodeEmitter.cpp | 20 +++++++++++--- llvm/test/MC/ELF/relocation-tls.s | 26 ------------------- llvm/test/MC/X86/tlsdesc-32.s | 19 ++++++++++++++ llvm/test/MC/X86/tlsdesc-64.s | 19 ++++++++++++++ 6 files changed, 61 insertions(+), 29 deletions(-) delete mode 100644 llvm/test/MC/ELF/relocation-tls.s create mode 100644 llvm/test/MC/X86/tlsdesc-32.s create mode 100644 llvm/test/MC/X86/tlsdesc-64.s diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp index 6fe16abd5a3a..245dd063004f 100644 --- a/llvm/lib/MC/MCELFStreamer.cpp +++ b/llvm/lib/MC/MCELFStreamer.cpp @@ -400,6 +400,8 @@ void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) { case MCSymbolRefExpr::VK_INDNTPOFF: case MCSymbolRefExpr::VK_NTPOFF: case MCSymbolRefExpr::VK_GOTNTPOFF: + case MCSymbolRefExpr::VK_TLSCALL: + case MCSymbolRefExpr::VK_TLSDESC: case MCSymbolRefExpr::VK_TLSGD: case MCSymbolRefExpr::VK_TLSLD: case MCSymbolRefExpr::VK_TLSLDM: diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp index e6939839d281..232a06593238 100644 --- a/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp +++ b/llvm/lib/Target/X86/MCTargetDesc/X86ELFObjectWriter.cpp @@ -271,6 +271,10 @@ static unsigned getRelocType32(MCContext &Ctx, assert(Type == RT32_32); assert(!IsPCRel); return ELF::R_386_GOTOFF; + case MCSymbolRefExpr::VK_TLSCALL: + return ELF::R_386_TLS_DESC_CALL; + case MCSymbolRefExpr::VK_TLSDESC: + return ELF::R_386_TLS_GOTDESC; case MCSymbolRefExpr::VK_TPOFF: assert(Type == RT32_32); assert(!IsPCRel); diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp index 8eb48fcb0bb7..31d26d08a63f 100644 --- a/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp +++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp @@ -524,9 +524,23 @@ void X86MCCodeEmitter::emitMemModRMByte(const MCInst &MI, unsigned Op, // indirect register encoding, this handles addresses like [EAX]. The // encoding for [EBP] with no displacement means [disp32] so we handle it // by emitting a displacement of 0 below. - if (Disp.isImm() && Disp.getImm() == 0 && BaseRegNo != N86::EBP) { - EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS); - return; + if (BaseRegNo != N86::EBP) { + if (Disp.isImm() && Disp.getImm() == 0) { + EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS); + return; + } + + // If the displacement is @tlscall, treat it as a zero. + if (Disp.isExpr()) { + auto *Sym = dyn_cast(Disp.getExpr()); + if (Sym && Sym->getKind() == MCSymbolRefExpr::VK_TLSCALL) { + // This is exclusively used by call *a@tlscall(base). The relocation + // (R_386_TLSCALL or R_X86_64_TLSCALL) applies to the beginning. + Fixups.push_back(MCFixup::create(0, Sym, FK_NONE, MI.getLoc())); + EmitByte(ModRMByte(0, RegOpcodeField, BaseRegNo), CurByte, OS); + return; + } + } } // Otherwise, if the displacement fits in a byte, encode as [REG+disp8]. diff --git a/llvm/test/MC/ELF/relocation-tls.s b/llvm/test/MC/ELF/relocation-tls.s deleted file mode 100644 index 00b4046ad342..000000000000 --- a/llvm/test/MC/ELF/relocation-tls.s +++ /dev/null @@ -1,26 +0,0 @@ -// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | llvm-readobj -S --sr | FileCheck %s - -// Test that we produce the correct relocation. - - leaq _ZL3ccc@TLSDESC(%rip), %rax - call *_ZL3ccc@TLSCALL(%rax) - addq %fs:0, %rax - -// CHECK: Section { -// CHECK: Index: -// CHECK: Name: .rela.text -// CHECK-NEXT: Type: SHT_RELA -// CHECK-NEXT: Flags [ -// CHECK-NEXT: ] -// CHECK-NEXT: Address: 0x0 -// CHECK-NEXT: Offset: -// CHECK-NEXT: Size: -// CHECK-NEXT: Link: -// CHECK-NEXT: Info: -// CHECK-NEXT: AddressAlignment: 8 -// CHECK-NEXT: EntrySize: 24 -// CHECK-NEXT: Relocations [ -// CHECK-NEXT: 0x3 R_X86_64_GOTPC32_TLSDESC _ZL3ccc 0xFFFFFFFFFFFFFFFC -// CHECK-NEXT: 0x9 R_X86_64_TLSDESC_CALL _ZL3ccc 0x0 -// CHECK-NEXT: ] -// CHECK-NEXT: } diff --git a/llvm/test/MC/X86/tlsdesc-32.s b/llvm/test/MC/X86/tlsdesc-32.s new file mode 100644 index 000000000000..866bda65b94f --- /dev/null +++ b/llvm/test/MC/X86/tlsdesc-32.s @@ -0,0 +1,19 @@ +# RUN: llvm-mc -triple i386-pc-linux-musl %s | FileCheck --check-prefix=PRINT %s + +# RUN: llvm-mc -filetype=obj -triple i386-pc-linux-musl %s -o %t +# RUN: llvm-readelf -s %t | FileCheck --check-prefix=SYM %s +# RUN: llvm-objdump -dr --no-show-raw-insn %t | FileCheck %s + +# PRINT: leal a@tlsdesc(%ebx), %eax +# PRINT-NEXT: calll *a@tlscall(%eax) + +# SYM: TLS GLOBAL DEFAULT UND a + +# CHECK: 0: leal (%ebx), %eax +# CHECK-NEXT: 00000002: R_386_TLS_GOTDESC a +# CHECK-NEXT: 6: calll *(%eax) +# CHECK-NEXT: 00000006: R_386_TLS_DESC_CALL a + +leal a@tlsdesc(%ebx), %eax +call *a@tlscall(%eax) +addl %gs:0, %eax diff --git a/llvm/test/MC/X86/tlsdesc-64.s b/llvm/test/MC/X86/tlsdesc-64.s new file mode 100644 index 000000000000..6da468aa5aa1 --- /dev/null +++ b/llvm/test/MC/X86/tlsdesc-64.s @@ -0,0 +1,19 @@ +# RUN: llvm-mc -triple x86_64-pc-linux-musl %s | FileCheck --check-prefix=PRINT %s + +# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-musl %s -o %t +# RUN: llvm-readelf -s %t | FileCheck --check-prefix=SYM %s +# RUN: llvm-objdump -dr --no-show-raw-insn %t | FileCheck --match-full-lines %s + +# PRINT: leaq a@tlsdesc(%rip), %rax +# PRINT-NEXT: callq *a@tlscall(%rax) + +# SYM: TLS GLOBAL DEFAULT UND a + +# CHECK: 0: leaq (%rip), %rax +# CHECK-NEXT: 0000000000000003: R_X86_64_GOTPC32_TLSDESC a-4 +# CHECK-NEXT: 7: callq *(%rax) +# CHECK-NEXT: 0000000000000007: R_X86_64_TLSDESC_CALL a + +leaq a@tlsdesc(%rip), %rax +call *a@tlscall(%rax) +addq %fs:0, %rax