This revision was not accepted when it landed; it landed in state "Needs Review". This revision was automatically updated to reflect the committed changes. Closed by commit rG14fc20ca6282: Align branches within 32-Byte boundary (NOP padding) (authored by reames).
Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D70157/new/ https://reviews.llvm.org/D70157 Files: llvm/include/llvm/MC/MCAsmBackend.h llvm/include/llvm/MC/MCAssembler.h llvm/include/llvm/MC/MCFragment.h llvm/include/llvm/MC/MCObjectStreamer.h llvm/lib/MC/MCAssembler.cpp llvm/lib/MC/MCFragment.cpp llvm/lib/MC/MCObjectStreamer.cpp llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp llvm/test/MC/X86/align-branch-32-1a.s llvm/test/MC/X86/align-branch-64-1a.s llvm/test/MC/X86/align-branch-64-1b.s llvm/test/MC/X86/align-branch-64-1c.s llvm/test/MC/X86/align-branch-64-1d.s llvm/test/MC/X86/align-branch-64-2a.s llvm/test/MC/X86/align-branch-64-2b.s llvm/test/MC/X86/align-branch-64-2c.s llvm/test/MC/X86/align-branch-64-3a.s llvm/test/MC/X86/align-branch-64-4a.s llvm/test/MC/X86/align-branch-64-5a.s llvm/test/MC/X86/align-branch-64-5b.s
Index: llvm/test/MC/X86/align-branch-64-5b.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-5b.s @@ -0,0 +1,50 @@ +# Check option --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc+jmp+indirect+call+ret can cowork with option --mc-relax-all +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc+jmp+indirect+call+ret --mc-relax-all %s | llvm-objdump -d - > %t1 +# RUN: FileCheck --input-file=%t1 %s + +# CHECK: 0000000000000000 foo: +# CHECK-NEXT: 0: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 8: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 10: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 18: c1 e9 02 shrl $2, %ecx +# CHECK-NEXT: 1b: 89 d1 movl %edx, %ecx +# CHECK-NEXT: 1d: 90 nop +# CHECK-NEXT: 1e: 90 nop +# CHECK-NEXT: 1f: 90 nop +# CHECK-NEXT: 20: 0f 85 f5 ff ff ff jne {{.*}} +# CHECK-NEXT: 26: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 2e: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 36: f6 c2 02 testb $2, %dl +# CHECK-NEXT: 39: 0f 85 e7 ff ff ff jne {{.*}} +# CHECK-NEXT: 3f: 90 nop +# CHECK-NEXT: 40: e9 d6 ff ff ff jmp {{.*}} +# CHECK-NEXT: 45: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 4d: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 55: 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 5d: 90 nop +# CHECK-NEXT: 5e: 90 nop +# CHECK-NEXT: 5f: 90 nop +# CHECK-NEXT: 60: e8 9b ff ff ff callq {{.*}} +# CHECK-NEXT: 65: e9 bc ff ff ff jmp {{.*}} + .text + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + shrl $2, %ecx +.L1: + movl %edx, %ecx + jne .L1 +.L2: + .rept 2 + movl %eax, %fs:0x1 + .endr + testb $2, %dl + jne .L2 + jmp .L1 + .rept 3 + movl %eax, %fs:0x1 + .endr + call foo + jmp .L2 Index: llvm/test/MC/X86/align-branch-64-5a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-5a.s @@ -0,0 +1,43 @@ +# Check no nop is inserted if no branch cross or is against the boundary +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc+jmp+indirect+call+ret %s | llvm-objdump -d - > %t1 +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s | llvm-objdump -d - > %t2 +# RUN: cmp %t1 %t2 +# RUN: FileCheck --input-file=%t1 %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 18: c1 e9 02 shrl $2, %ecx +# CHECK-NEXT: 1b: 89 d1 movl %edx, %ecx +# CHECK-NEXT: 1d: 75 fc jne {{.*}} +# CHECK-NEXT: 1f: 55 pushq %rbp +# CHECK-NEXT: 20: f6 c2 02 testb $2, %dl +# CHECK-NEXT: 23: 75 fa jne {{.*}} +# CHECK-COUNT-2: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 35: c1 e9 02 shrl $2, %ecx +# CHECK-NEXT: 38: e8 c3 ff ff ff callq {{.*}} +# CHECK-NEXT: 3d: ff e0 jmpq *%rax +# CHECK-NEXT: 3f: 55 pushq %rbp +# CHECK-NEXT: 40: c2 63 00 retq $99 + + .text + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + shrl $2, %ecx +.L1: + movl %edx, %ecx + jne .L1 +.L2: + push %rbp + testb $2, %dl + jne .L2 + .rept 2 + movl %eax, %fs:0x1 + .endr + shrl $2, %ecx + call foo + jmp *%rax + push %rbp + ret $99 Index: llvm/test/MC/X86/align-branch-64-4a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-4a.s @@ -0,0 +1,33 @@ +# Check only rets are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=ret +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=ret %s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-2: : 48 89 e5 movq %rsp, %rbp +# CHECK: 1e: 5a popq %rdx +# CHECK-NEXT: 1f: 90 nop +# CHECK-NEXT: 20: c3 retq +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 39: 89 75 f4 movl %esi, -12(%rbp) +# CHECK-NEXT: 3c: 31 c0 xorl %eax, %eax +# CHECK-COUNT-2: : 90 nop +# CHECK: 40: c2 1e 00 retq $30 + + .text + .globl foo + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + .rept 2 + movq %rsp, %rbp + .endr + popq %rdx + ret + .rept 3 + movl %eax, %fs:0x1 + .endr + movl %esi, -12(%rbp) + xorl %eax, %eax + ret $30 Index: llvm/test/MC/X86/align-branch-64-3a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-3a.s @@ -0,0 +1,41 @@ +# Check NOP padding is disabled before instruction that has variant symbol operand. +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=jmp+call %s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-2: : 48 89 e5 movq %rsp, %rbp +# CHECK: 1e: e8 00 00 00 00 callq {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3b: 55 pushq %rbp +# CHECK-NEXT: 3c: 89 75 f4 movl %esi, -12(%rbp) +# CHECK-NEXT: 3f: ff 15 00 00 00 00 callq *(%rip) +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5d: ff 15 00 00 00 00 callq *(%rip) +# CHECK-NEXT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 7b: ff 25 00 00 00 00 jmpq *(%rip) + + .text + .globl foo + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + .rept 2 + movq %rsp, %rbp + .endr + call __tls_get_addr@PLT + .rept 3 + movl %eax, %fs:0x1 + .endr + pushq %rbp + movl %esi, -12(%rbp) + call *__tls_get_addr@GOTPCREL(%rip) + .rept 3 + movl %eax, %fs:0x1 + .endr + call *foo@GOTPCREL(%rip) + .rept 3 + movl %eax, %fs:0x1 + .endr + jmp *foo@GOTPCREL(%rip) Index: llvm/test/MC/X86/align-branch-64-2c.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-2c.s @@ -0,0 +1,19 @@ +# Check only indirect jumps and calls are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=indirect+call +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=indirect+call %S/align-branch-64-2a.s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-2: : 89 75 f4 movl %esi, -12(%rbp) +# CHECK-COUNT-2: : 90 nop +# CHECK: 20: ff e0 jmpq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3a: 89 75 f4 movl %esi, -12(%rbp) +# CHECK-NEXT: 3d: 55 pushq %rbp +# CHECK-COUNT-2: : 90 nop +# CHECK: 40: ff d0 callq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5a: 55 pushq %rbp +# CHECK-COUNT-5: : 90 nop +# CHECK: 60: e8 9b ff ff ff callq {{.*}} +# CHECK-COUNT-4: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 85: ff 14 25 00 00 00 00 callq *0 Index: llvm/test/MC/X86/align-branch-64-2b.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-2b.s @@ -0,0 +1,17 @@ +# Check only calls are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=call +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=call %S/align-branch-64-2a.s| llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-2: : 89 75 f4 movl %esi, -12(%rbp) +# CHECK: 1e: ff e0 jmpq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 38: 89 75 f4 movl %esi, -12(%rbp) +# CHECK-NEXT: 3b: 55 pushq %rbp +# CHECK-NEXT: 3c: ff d0 callq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 56: 55 pushq %rbp +# CHECK-NEXT: 57: e8 a4 ff ff ff callq {{.*}} +# CHECK-COUNT-4: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-4: : 90 nop +# CHECK: 80: ff 14 25 00 00 00 00 callq *0 Index: llvm/test/MC/X86/align-branch-64-2a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-2a.s @@ -0,0 +1,44 @@ +# Check only indirect jumps are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=indirect +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=indirect %s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-COUNT-2: : 89 75 f4 movl %esi, -12(%rbp) +# CHECK-COUNT-2: : 90 nop +# CHECK: 20: ff e0 jmpq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3a: 89 75 f4 movl %esi, -12(%rbp) +# CHECK-NEXT: 3d: 55 pushq %rbp +# CHECK-NEXT: 3e: ff d0 callq *%rax +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 58: 55 pushq %rbp +# CHECK-NEXT: 59: e8 a2 ff ff ff callq {{.*}} +# CHECK-COUNT-4: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 7e: ff 14 25 00 00 00 00 callq *0 + + .text + .globl foo + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + .rept 2 + movl %esi, -12(%rbp) + .endr + jmp *%rax + .rept 3 + movl %eax, %fs:0x1 + .endr + movl %esi, -12(%rbp) + pushq %rbp + call *%rax + .rept 3 + movl %eax, %fs:0x1 + .endr + pushq %rbp + call foo + .rept 4 + movl %eax, %fs:0x1 + .endr + call *foo Index: llvm/test/MC/X86/align-branch-64-1d.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-1d.s @@ -0,0 +1,38 @@ +# Check only conditional jumps and unconditional jumps are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=jcc+jmp +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=jcc+jmp %S/align-branch-64-1a.s | llvm-objdump -d - > %t1 +# RUN: FileCheck --input-file=%t1 %s --check-prefixes=CHECK,SHORT-NOP + +# Check long NOP can be emitted to align branch if the target cpu support long nop. +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 -mcpu=x86-64 --x86-align-branch=jcc+jmp %S/align-branch-64-1a.s | llvm-objdump -d - >%t2 +# RUN: FileCheck --input-file=%t2 %s --check-prefixes=CHECK,LONG-NOP + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 18: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 1b: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 1d: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 20: 74 5d je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3a: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 3c: 74 41 je {{.*}} +# CHECK-NEXT: 3e: 5d popq %rbp +# CHECK-NEXT: 3f: 90 nop +# CHECK-NEXT: 40: 74 3d je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5a: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 5c: eb 27 jmp {{.*}} +# SHORT-NOP-COUNT-2: : 90 nop +# LONG-NOP: 5e: 66 90 nop +# CHECK-NEXT: 60: eb 23 jmp {{.*}} +# CHECK-NEXT: 62: eb 21 jmp {{.*}} +# CHECK-COUNT-2: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 74: 89 45 fc movl %eax, -4(%rbp) +# CHECK-NEXT: 77: 5d popq %rbp +# CHECK-NEXT: 78: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 7b: 74 02 je {{.*}} +# CHECK-NEXT: 7d: eb 06 jmp {{.*}} +# CHECK-NEXT: 7f: 8b 45 f4 movl -12(%rbp), %eax +# CHECK-NEXT: 82: 89 45 fc movl %eax, -4(%rbp) +# CHECK-COUNT-10: : 89 b5 50 fb ff ff movl %esi, -1200(%rbp) +# CHECK: c1: eb c2 jmp {{.*}} +# CHECK-NEXT: c3: c3 retq Index: llvm/test/MC/X86/align-branch-64-1c.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-1c.s @@ -0,0 +1,31 @@ +# Check only conditional jumps are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=jcc +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=jcc %S/align-branch-64-1a.s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 18: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 1b: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 1d: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 20: 74 5b je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3a: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 3c: 74 3f je {{.*}} +# CHECK-NEXT: 3e: 5d popq %rbp +# CHECK-NEXT: 3f: 90 nop +# CHECK-NEXT: 40: 74 3b je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5a: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 5c: eb 25 jmp {{.*}} +# CHECK-NEXT: 5e: eb 23 jmp {{.*}} +# CHECK-NEXT: 60: eb 21 jmp {{.*}} +# CHECK-COUNT-2: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 72: 89 45 fc movl %eax, -4(%rbp) +# CHECK-NEXT: 75: 5d popq %rbp +# CHECK-NEXT: 76: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 79: 74 02 je {{.*}} +# CHECK-NEXT: 7b: eb 06 jmp {{.*}} +# CHECK-NEXT: 7d: 8b 45 f4 movl -12(%rbp), %eax +# CHECK-NEXT: 80: 89 45 fc movl %eax, -4(%rbp) +# CHECK-COUNT-10: : 89 b5 50 fb ff ff movl %esi, -1200(%rbp) +# CHECK: bf: eb c2 jmp {{.*}} +# CHECK-NEXT: c1: c3 retq Index: llvm/test/MC/X86/align-branch-64-1b.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-1b.s @@ -0,0 +1,32 @@ +# Check only fused conditional jumps and conditional jumps are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc %S/align-branch-64-1a.s | llvm-objdump -d - | FileCheck %s + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 18: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 1b: 31 c0 xorl %eax, %eax +# CHECK-COUNT-3: : 90 nop +# CHECK-NEXT: 20: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 23: 74 5b je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3d: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 3f: 90 nop +# CHECK-NEXT: 40: 74 3e je {{.*}} +# CHECK-NEXT: 42: 5d popq %rbp +# CHECK-NEXT: 43: 74 3b je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5d: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 5f: eb 25 jmp {{.*}} +# CHECK-NEXT: 61: eb 23 jmp {{.*}} +# CHECK-NEXT: 63: eb 21 jmp {{.*}} +# CHECK-COUNT-2: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 75: 89 45 fc movl %eax, -4(%rbp) +# CHECK: 78: 5d popq %rbp +# CHECK-NEXT: 79: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 7c: 74 02 je {{.*}} +# CHECK-NEXT: 7e: eb 06 jmp {{.*}} +# CHECK-NEXT: 80: 8b 45 f4 movl -12(%rbp), %eax +# CHECK-NEXT: 83: 89 45 fc movl %eax, -4(%rbp) +# CHECK-COUNT-10: : 89 b5 50 fb ff ff movl %esi, -1200(%rbp) +# CHECK: c2: eb c2 jmp {{.*}} +# CHECK-NEXT: c4: c3 retq Index: llvm/test/MC/X86/align-branch-64-1a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-64-1a.s @@ -0,0 +1,83 @@ +# Check only fused conditional jumps, conditional jumps and unconditional jumps are aligned with option --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc+jmp +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=fused+jcc+jmp %s | llvm-objdump -d - > %t1 +# RUN: FileCheck --input-file=%t1 %s + +# Check no branches is aligned with option --x86-align-branch-boundary=0 +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown --x86-align-branch-boundary=0 --x86-align-branch=fused+jcc+jmp %s | llvm-objdump -d - > %t2 +# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s | llvm-objdump -d - > %t3 +# RUN: cmp %t2 %t3 + +# CHECK: 0000000000000000 foo: +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 18: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 1b: 31 c0 xorl %eax, %eax +# CHECK-COUNT-3: : 90 nop +# CHECK: 20: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 23: 74 5d je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3d: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 3f: 90 nop +# CHECK-NEXT: 40: 74 40 je {{.*}} +# CHECK-NEXT: 42: 5d popq %rbp +# CHECK-NEXT: 43: 74 3d je {{.*}} +# CHECK-COUNT-3: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5d: 31 c0 xorl %eax, %eax +# CHECK-NEXT: 5f: 90 nop +# CHECK-NEXT: 60: eb 26 jmp {{.*}} +# CHECK-NEXT: 62: eb 24 jmp {{.*}} +# CHECK-NEXT: 64: eb 22 jmp {{.*}} +# CHECK-COUNT-2: : 64 89 04 25 01 00 00 00 movl %eax, %fs:1 +# CHECK: 76: 89 45 fc movl %eax, -4(%rbp) +# CHECK-NEXT: 79: 5d popq %rbp +# CHECK-NEXT: 7a: 48 39 c5 cmpq %rax, %rbp +# CHECK-NEXT: 7d: 74 03 je {{.*}} +# CHECK-NEXT: 7f: 90 nop +# CHECK-NEXT: 80: eb 06 jmp {{.*}} +# CHECK-NEXT: 82: 8b 45 f4 movl -12(%rbp), %eax +# CHECK-NEXT: 85: 89 45 fc movl %eax, -4(%rbp) +# CHECK-COUNT-10: : 89 b5 50 fb ff ff movl %esi, -1200(%rbp) +# CHECK: c4: eb c2 jmp {{.*}} +# CHECK-NEXT: c6: c3 retq + + .text + .globl foo + .p2align 4 +foo: + .rept 3 + movl %eax, %fs:0x1 + .endr + cmp %rax, %rbp + xorl %eax, %eax + cmp %rax, %rbp + je .L_2 + .rept 3 + movl %eax, %fs:0x1 + .endr + xorl %eax, %eax + je .L_2 + popq %rbp + je .L_2 + .rept 3 + movl %eax, %fs:0x1 + .endr + xorl %eax, %eax + jmp .L_3 + jmp .L_3 + jmp .L_3 + .rept 2 + movl %eax, %fs:0x1 + .endr + movl %eax, -4(%rbp) + popq %rbp + cmp %rax, %rbp + je .L_2 + jmp .L_3 +.L_2: + movl -12(%rbp), %eax + movl %eax, -4(%rbp) +.L_3: + .rept 10 + movl %esi, -1200(%rbp) + .endr + jmp .L_3 + retq Index: llvm/test/MC/X86/align-branch-32-1a.s =================================================================== --- /dev/null +++ llvm/test/MC/X86/align-branch-32-1a.s @@ -0,0 +1,38 @@ +# Check NOP padding is disabled before instruction that has variant symbol operand. +# RUN: llvm-mc -filetype=obj -triple i386-unknown-unknown --x86-align-branch-boundary=32 --x86-align-branch=call %s | llvm-objdump -d - | FileCheck %s + +# CHECK: 00000000 foo: +# CHECK-COUNT-5: : 64 a3 01 00 00 00 movl %eax, %fs:1 +# CHECK: 1e: e8 fc ff ff ff calll {{.*}} +# CHECK-COUNT-4: : 64 a3 01 00 00 00 movl %eax, %fs:1 +# CHECK: 3b: 55 pushl %ebp +# CHECK-NEXT: 3c: ff 91 00 00 00 00 calll *(%ecx) +# CHECK-COUNT-4: : 64 a3 01 00 00 00 movl %eax, %fs:1 +# CHECK: 5a: c1 e9 02 shrl $2, %ecx +# CHECK-NEXT: 5d: 55 pushl %ebp +# CHECK-NEXT: 5e: ff 10 calll *(%eax) +# CHECK-COUNT-5: : 64 a3 01 00 00 00 movl %eax, %fs:1 +# CHECK-NEXT: 7e: ff 20 jmpl *(%eax) + .text + .globl foo + .p2align 4 +foo: + .rept 5 + movl %eax, %fs:0x1 + .endr + call ___tls_get_addr@PLT + .rept 4 + movl %eax, %fs:0x1 + .endr + pushl %ebp + call *___tls_get_addr@GOT(%ecx) + .rept 4 + movl %eax, %fs:0x1 + .endr + shrl $2, %ecx + pushl %ebp + call *foo@tlscall(%eax) + .rept 5 + movl %eax, %fs:0x1 + .endr + jmp *foo@tlscall(%eax) Index: llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp =================================================================== --- llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp +++ llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp @@ -19,14 +19,19 @@ #include "llvm/MC/MCExpr.h" #include "llvm/MC/MCFixupKindInfo.h" #include "llvm/MC/MCInst.h" +#include "llvm/MC/MCInstrInfo.h" #include "llvm/MC/MCMachObjectWriter.h" +#include "llvm/MC/MCObjectStreamer.h" #include "llvm/MC/MCObjectWriter.h" #include "llvm/MC/MCRegisterInfo.h" #include "llvm/MC/MCSectionMachO.h" #include "llvm/MC/MCSubtargetInfo.h" #include "llvm/MC/MCValue.h" +#include "llvm/Support/CommandLine.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/raw_ostream.h" +#include "llvm/Support/TargetRegistry.h" + using namespace llvm; static unsigned getFixupKindSize(unsigned Kind) { @@ -64,6 +69,71 @@ } namespace { +class X86AlignBranchKind { +private: + uint8_t AlignBranchKind = 0; + +public: + enum Flag : uint8_t { + AlignBranchNone = 0, + AlignBranchFused = 1U << 0, + AlignBranchJcc = 1U << 1, + AlignBranchJmp = 1U << 2, + AlignBranchCall = 1U << 3, + AlignBranchRet = 1U << 4, + AlignBranchIndirect = 1U << 5 + }; + + void operator=(const std::string &Val) { + if (Val.empty()) + return; + SmallVector<StringRef, 6> BranchTypes; + StringRef(Val).split(BranchTypes, '+', -1, false); + for (auto BranchType : BranchTypes) { + if (BranchType == "fused") + addKind(AlignBranchFused); + else if (BranchType == "jcc") + addKind(AlignBranchJcc); + else if (BranchType == "jmp") + addKind(AlignBranchJmp); + else if (BranchType == "call") + addKind(AlignBranchCall); + else if (BranchType == "ret") + addKind(AlignBranchRet); + else if (BranchType == "indirect") + addKind(AlignBranchIndirect); + else { + report_fatal_error( + "'-x86-align-branch 'The branches's type is combination of jcc, " + "fused, jmp, call, ret, indirect.(plus separated)", + false); + } + } + } + + operator uint8_t() const { return AlignBranchKind; } + void addKind(Flag Value) { AlignBranchKind |= Value; } +}; + +X86AlignBranchKind X86AlignBranchKindLoc; + +cl::opt<uint64_t> X86AlignBranchBoundary( + "x86-align-branch-boundary", cl::init(0), + cl::desc( + "Control how the assembler should align branches with NOP. If the " + "boundary's size is not 0, it should be a power of 2 and no less " + "than 32. Branches will be aligned within the boundary of specified " + "size. -x86-align-branch-boundary=0 doesn't align branches.")); + +cl::opt<X86AlignBranchKind, true, cl::parser<std::string>> X86AlignBranch( + "x86-align-branch", + cl::desc("Specify types of branches to align (plus separated list of " + "types). The branches's type is combination of jcc, fused, " + "jmp, call, ret, indirect."), + cl::value_desc("jcc(conditional jump), fused(fused conditional jump), " + "jmp(unconditional jump); call(call); ret(ret), " + "indirect(indirect jump)."), + cl::location(X86AlignBranchKindLoc)); class X86ELFObjectWriter : public MCELFObjectTargetWriter { public: @@ -74,9 +144,31 @@ class X86AsmBackend : public MCAsmBackend { const MCSubtargetInfo &STI; + const MCInstrInfo &MCII; + X86AlignBranchKind AlignBranchType; + Align AlignBoundary; + + bool isFirstMacroFusibleInst(const MCInst &Inst) const; + bool isMacroFused(const MCInst &Cmp, const MCInst &Jcc) const; + bool isRIPRelative(const MCInst &MI) const; + bool hasVariantSymbol(const MCInst &MI) const; + + bool needAlign(MCObjectStreamer &OS) const; + bool needAlignInst(const MCInst &Inst) const; + MCBoundaryAlignFragment * + getOrCreateBoundaryAlignFragment(MCObjectStreamer &OS) const; + MCInst PrevInst; + public: X86AsmBackend(const Target &T, const MCSubtargetInfo &STI) - : MCAsmBackend(support::little), STI(STI) {} + : MCAsmBackend(support::little), STI(STI), + MCII(*(T.createMCInstrInfo())) { + AlignBoundary = assumeAligned(X86AlignBranchBoundary); + AlignBranchType = X86AlignBranchKindLoc; + } + + void alignBranchesBegin(MCObjectStreamer &OS, const MCInst &Inst) override; + void alignBranchesEnd(MCObjectStreamer &OS, const MCInst &Inst) override; unsigned getNumFixupKinds() const override { return X86::NumTargetFixupKinds; @@ -258,6 +350,199 @@ return getRelaxedOpcodeBranch(Inst, is16BitMode); } +static X86::CondCode getCondFromBranch(const MCInst &MI, + const MCInstrInfo &MCII) { + unsigned Opcode = MI.getOpcode(); + switch (Opcode) { + default: + return X86::COND_INVALID; + case X86::JCC_1: { + const MCInstrDesc &Desc = MCII.get(Opcode); + return static_cast<X86::CondCode>( + MI.getOperand(Desc.getNumOperands() - 1).getImm()); + } + } +} + +static X86::SecondMacroFusionInstKind +classifySecondInstInMacroFusion(const MCInst &MI, const MCInstrInfo &MCII) { + X86::CondCode CC = getCondFromBranch(MI, MCII); + return classifySecondCondCodeInMacroFusion(CC); +} + +/// Check if the instruction is valid as the first instruction in macro fusion. +bool X86AsmBackend::isFirstMacroFusibleInst(const MCInst &Inst) const { + // An Intel instruction with RIP relative addressing is not macro fusible. + if (isRIPRelative(Inst)) + return false; + X86::FirstMacroFusionInstKind FIK = + X86::classifyFirstOpcodeInMacroFusion(Inst.getOpcode()); + return FIK != X86::FirstMacroFusionInstKind::Invalid; +} + +/// Check if the two instructions are macro-fused. +bool X86AsmBackend::isMacroFused(const MCInst &Cmp, const MCInst &Jcc) const { + const MCInstrDesc &InstDesc = MCII.get(Jcc.getOpcode()); + if (!InstDesc.isConditionalBranch()) + return false; + if (!isFirstMacroFusibleInst(Cmp)) + return false; + const X86::FirstMacroFusionInstKind CmpKind = + X86::classifyFirstOpcodeInMacroFusion(Cmp.getOpcode()); + const X86::SecondMacroFusionInstKind BranchKind = + classifySecondInstInMacroFusion(Jcc, MCII); + return X86::isMacroFused(CmpKind, BranchKind); +} + +/// Check if the instruction is RIP relative addressing. +bool X86AsmBackend::isRIPRelative(const MCInst &MI) const { + unsigned Opcode = MI.getOpcode(); + const MCInstrDesc &Desc = MCII.get(Opcode); + uint64_t TSFlags = Desc.TSFlags; + unsigned CurOp = X86II::getOperandBias(Desc); + int MemoryOperand = X86II::getMemoryOperandNo(TSFlags); + if (MemoryOperand >= 0) { + unsigned BaseRegNum = MemoryOperand + CurOp + X86::AddrBaseReg; + unsigned BaseReg = MI.getOperand(BaseRegNum).getReg(); + if (BaseReg == X86::RIP) + return true; + } + return false; +} + +/// Check if the instruction has variant symbol operand. +bool X86AsmBackend::hasVariantSymbol(const MCInst &MI) const { + + for (auto &Operand : MI) { + if (Operand.isExpr()) { + const MCExpr &Expr = *Operand.getExpr(); + if (Expr.getKind() == MCExpr::SymbolRef && + cast<MCSymbolRefExpr>(*Operand.getExpr()).getKind() != + MCSymbolRefExpr::VK_None) + return true; + } + } + return false; +} + +bool X86AsmBackend::needAlign(MCObjectStreamer &OS) const { + if (AlignBoundary == Align::None() || + AlignBranchType == X86AlignBranchKind::AlignBranchNone) + return false; + + MCAssembler &Assembler = OS.getAssembler(); + MCSection *Sec = OS.getCurrentSectionOnly(); + // To be Done: Currently don't deal with Bundle cases. + if (Assembler.isBundlingEnabled() && Sec->isBundleLocked()) + return false; + + // Branches only need to be aligned in 32-bit or 64-bit mode. + if (!(STI.getFeatureBits()[X86::Mode64Bit] || + STI.getFeatureBits()[X86::Mode32Bit])) + return false; + + return true; +} + +/// Check if the instruction operand needs to be aligned. Padding is disabled +/// before intruction which may be rewritten by linker(e.g. TLSCALL). +bool X86AsmBackend::needAlignInst(const MCInst &Inst) const { + // Linker may rewrite the instruction with variant symbol operand. + if (hasVariantSymbol(Inst)) + return false; + + const MCInstrDesc &InstDesc = MCII.get(Inst.getOpcode()); + return (InstDesc.isConditionalBranch() && + (AlignBranchType & X86AlignBranchKind::AlignBranchJcc)) || + (InstDesc.isUnconditionalBranch() && + (AlignBranchType & X86AlignBranchKind::AlignBranchJmp)) || + (InstDesc.isCall() && + (AlignBranchType & X86AlignBranchKind::AlignBranchCall)) || + (InstDesc.isReturn() && + (AlignBranchType & X86AlignBranchKind::AlignBranchRet)) || + (InstDesc.isIndirectBranch() && + (AlignBranchType & X86AlignBranchKind::AlignBranchIndirect)); +} + +static bool canReuseBoundaryAlignFragment(const MCBoundaryAlignFragment &F) { + // If a MCBoundaryAlignFragment has not been used to emit NOP,we can reuse it. + return !F.canEmitNops(); +} + +MCBoundaryAlignFragment * +X86AsmBackend::getOrCreateBoundaryAlignFragment(MCObjectStreamer &OS) const { + auto *F = dyn_cast_or_null<MCBoundaryAlignFragment>(OS.getCurrentFragment()); + if (!F || !canReuseBoundaryAlignFragment(*F)) { + F = new MCBoundaryAlignFragment(AlignBoundary); + OS.insert(F); + } + return F; +} + +/// Insert MCBoundaryAlignFragment before instructions to align branches. +void X86AsmBackend::alignBranchesBegin(MCObjectStreamer &OS, + const MCInst &Inst) { + if (!needAlign(OS)) + return; + + MCFragment *CF = OS.getCurrentFragment(); + bool NeedAlignFused = AlignBranchType & X86AlignBranchKind::AlignBranchFused; + if (NeedAlignFused && isMacroFused(PrevInst, Inst) && CF) { + // Macro fusion actually happens and there is no other fragment inserted + // after the previous instruction. NOP can be emitted in PF to align fused + // jcc. + if (auto *PF = + dyn_cast_or_null<MCBoundaryAlignFragment>(CF->getPrevNode())) { + const_cast<MCBoundaryAlignFragment *>(PF)->setEmitNops(true); + const_cast<MCBoundaryAlignFragment *>(PF)->setFused(true); + } + } else if (needAlignInst(Inst)) { + // Note: When there is at least one fragment, such as MCAlignFragment, + // inserted after the previous instruction, e.g. + // + // \code + // cmp %rax %rcx + // .align 16 + // je .Label0 + // \ endcode + // + // We will treat the JCC as a unfused branch although it may be fused + // with the CMP. + auto *F = getOrCreateBoundaryAlignFragment(OS); + F->setEmitNops(true); + F->setFused(false); + } else if (NeedAlignFused && isFirstMacroFusibleInst(Inst)) { + // We don't know if macro fusion happens until the reaching the next + // instruction, so a place holder is put here if necessary. + getOrCreateBoundaryAlignFragment(OS); + } + + PrevInst = Inst; +} + +/// Insert a MCBoundaryAlignFragment to mark the end of the branch to be aligned +/// if necessary. +void X86AsmBackend::alignBranchesEnd(MCObjectStreamer &OS, const MCInst &Inst) { + if (!needAlign(OS)) + return; + // If the branch is emitted into a MCRelaxableFragment, we can determine the + // size of the branch easily in MCAssembler::relaxBoundaryAlign. When the + // branch is fused, the fused branch(macro fusion pair) must be emitted into + // two fragments. Or when the branch is unfused, the branch must be emitted + // into one fragment. The MCRelaxableFragment naturally marks the end of the + // fused or unfused branch. + // Otherwise, we need to insert a MCBoundaryAlignFragment to mark the end of + // the branch. This MCBoundaryAlignFragment may be reused to emit NOP to align + // other branch. + if (needAlignInst(Inst) && !isa<MCRelaxableFragment>(OS.getCurrentFragment())) + OS.insert(new MCBoundaryAlignFragment(AlignBoundary)); + + // Update the maximum alignment on the current section if necessary. + MCSection *Sec = OS.getCurrentSectionOnly(); + if (AlignBoundary.value() > Sec->getAlignment()) + Sec->setAlignment(AlignBoundary); +} + Optional<MCFixupKind> X86AsmBackend::getFixupKind(StringRef Name) const { if (STI.getTargetTriple().isOSBinFormatELF()) { if (STI.getTargetTriple().getArch() == Triple::x86_64) { Index: llvm/lib/MC/MCObjectStreamer.cpp =================================================================== --- llvm/lib/MC/MCObjectStreamer.cpp +++ llvm/lib/MC/MCObjectStreamer.cpp @@ -364,6 +364,13 @@ void MCObjectStreamer::EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI) { + getAssembler().getBackend().alignBranchesBegin(*this, Inst); + EmitInstructionImpl(Inst, STI); + getAssembler().getBackend().alignBranchesEnd(*this, Inst); +} + +void MCObjectStreamer::EmitInstructionImpl(const MCInst &Inst, + const MCSubtargetInfo &STI) { MCStreamer::EmitInstruction(Inst, STI); MCSection *Sec = getCurrentSectionOnly(); Index: llvm/lib/MC/MCFragment.cpp =================================================================== --- llvm/lib/MC/MCFragment.cpp +++ llvm/lib/MC/MCFragment.cpp @@ -275,6 +275,9 @@ case FT_LEB: delete cast<MCLEBFragment>(this); return; + case FT_BoundaryAlign: + delete cast<MCBoundaryAlignFragment>(this); + return; case FT_SymbolId: delete cast<MCSymbolIdFragment>(this); return; @@ -319,6 +322,7 @@ case MCFragment::FT_Dwarf: OS << "MCDwarfFragment"; break; case MCFragment::FT_DwarfFrame: OS << "MCDwarfCallFrameFragment"; break; case MCFragment::FT_LEB: OS << "MCLEBFragment"; break; + case MCFragment::FT_BoundaryAlign: OS<<"MCBoundaryAlignFragment"; break; case MCFragment::FT_SymbolId: OS << "MCSymbolIdFragment"; break; case MCFragment::FT_CVInlineLines: OS << "MCCVInlineLineTableFragment"; break; case MCFragment::FT_CVDefRange: OS << "MCCVDefRangeTableFragment"; break; @@ -418,6 +422,19 @@ OS << " Value:" << LF->getValue() << " Signed:" << LF->isSigned(); break; } + case MCFragment::FT_BoundaryAlign: { + const auto *BF = cast<MCBoundaryAlignFragment>(this); + if (BF->canEmitNops()) + OS << " (can emit nops to align"; + if (BF->isFused()) + OS << " fused branch)"; + else + OS << " unfused branch)"; + OS << "\n "; + OS << " BoundarySize:" << BF->getAlignment().value() + << " Size:" << BF->getSize(); + break; + } case MCFragment::FT_SymbolId: { const MCSymbolIdFragment *F = cast<MCSymbolIdFragment>(this); OS << "\n "; Index: llvm/lib/MC/MCAssembler.cpp =================================================================== --- llvm/lib/MC/MCAssembler.cpp +++ llvm/lib/MC/MCAssembler.cpp @@ -309,6 +309,9 @@ case MCFragment::FT_LEB: return cast<MCLEBFragment>(F).getContents().size(); + case MCFragment::FT_BoundaryAlign: + return cast<MCBoundaryAlignFragment>(F).getSize(); + case MCFragment::FT_SymbolId: return 4; @@ -605,6 +608,13 @@ break; } + case MCFragment::FT_BoundaryAlign: { + if (!Asm.getBackend().writeNopData(OS, FragmentSize)) + report_fatal_error("unable to write nop sequence of " + + Twine(FragmentSize) + " bytes"); + break; + } + case MCFragment::FT_SymbolId: { const MCSymbolIdFragment &SF = cast<MCSymbolIdFragment>(F); support::endian::write<uint32_t>(OS, SF.getSymbol()->getIndex(), Endian); @@ -941,6 +951,72 @@ return OldSize != LF.getContents().size(); } +/// Check if the branch crosses the boundary. +/// +/// \param StartAddr start address of the fused/unfused branch. +/// \param Size size of the fused/unfused branch. +/// \param BoundaryAlignment aligment requirement of the branch. +/// \returns true if the branch cross the boundary. +static bool mayCrossBoundary(uint64_t StartAddr, uint64_t Size, + Align BoundaryAlignment) { + uint64_t EndAddr = StartAddr + Size; + return (StartAddr >> Log2(BoundaryAlignment)) != + ((EndAddr - 1) >> Log2(BoundaryAlignment)); +} + +/// Check if the branch is against the boundary. +/// +/// \param StartAddr start address of the fused/unfused branch. +/// \param Size size of the fused/unfused branch. +/// \param BoundaryAlignment aligment requirement of the branch. +/// \returns true if the branch is against the boundary. +static bool isAgainstBoundary(uint64_t StartAddr, uint64_t Size, + Align BoundaryAlignment) { + uint64_t EndAddr = StartAddr + Size; + return (EndAddr & (BoundaryAlignment.value() - 1)) == 0; +} + +/// Check if the branch needs padding. +/// +/// \param StartAddr start address of the fused/unfused branch. +/// \param Size size of the fused/unfused branch. +/// \param BoundaryAlignment aligment requirement of the branch. +/// \returns true if the branch needs padding. +static bool needPadding(uint64_t StartAddr, uint64_t Size, + Align BoundaryAlignment) { + return mayCrossBoundary(StartAddr, Size, BoundaryAlignment) || + isAgainstBoundary(StartAddr, Size, BoundaryAlignment); +} + +bool MCAssembler::relaxBoundaryAlign(MCAsmLayout &Layout, + MCBoundaryAlignFragment &BF) { + // The MCBoundaryAlignFragment that doesn't emit NOP should not be relaxed. + if (!BF.canEmitNops()) + return false; + + uint64_t AlignedOffset = Layout.getFragmentOffset(BF.getNextNode()); + uint64_t AlignedSize = 0; + const MCFragment *F = BF.getNextNode(); + // If the branch is unfused, it is emitted into one fragment, otherwise it is + // emitted into two fragments at most, the next MCBoundaryAlignFragment(if + // exists) also marks the end of the branch. + for (auto i = 0, N = BF.isFused() ? 2 : 1; + i != N && !isa<MCBoundaryAlignFragment>(F); ++i, F = F->getNextNode()) { + AlignedSize += computeFragmentSize(Layout, *F); + } + uint64_t OldSize = BF.getSize(); + AlignedOffset -= OldSize; + Align BoundaryAlignment = BF.getAlignment(); + uint64_t NewSize = needPadding(AlignedOffset, AlignedSize, BoundaryAlignment) + ? offsetToAlignment(AlignedOffset, BoundaryAlignment) + : 0U; + if (NewSize == OldSize) + return false; + BF.setSize(NewSize); + Layout.invalidateFragmentsFrom(&BF); + return true; +} + bool MCAssembler::relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF) { MCContext &Context = Layout.getAssembler().getContext(); @@ -1057,6 +1133,10 @@ case MCFragment::FT_LEB: RelaxedFrag = relaxLEB(Layout, *cast<MCLEBFragment>(I)); break; + case MCFragment::FT_BoundaryAlign: + RelaxedFrag = + relaxBoundaryAlign(Layout, *cast<MCBoundaryAlignFragment>(I)); + break; case MCFragment::FT_CVInlineLines: RelaxedFrag = relaxCVInlineLineTable(Layout, *cast<MCCVInlineLineTableFragment>(I)); Index: llvm/include/llvm/MC/MCObjectStreamer.h =================================================================== --- llvm/include/llvm/MC/MCObjectStreamer.h +++ llvm/include/llvm/MC/MCObjectStreamer.h @@ -53,6 +53,7 @@ void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) override; void EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) override; MCSymbol *EmitCFILabel() override; + void EmitInstructionImpl(const MCInst &Inst, const MCSubtargetInfo &STI); void resolvePendingFixups(); protected: Index: llvm/include/llvm/MC/MCFragment.h =================================================================== --- llvm/include/llvm/MC/MCFragment.h +++ llvm/include/llvm/MC/MCFragment.h @@ -16,6 +16,7 @@ #include "llvm/ADT/ilist_node.h" #include "llvm/MC/MCFixup.h" #include "llvm/MC/MCInst.h" +#include "llvm/Support/Alignment.h" #include "llvm/Support/Casting.h" #include "llvm/Support/SMLoc.h" #include <cstdint> @@ -41,6 +42,7 @@ FT_Dwarf, FT_DwarfFrame, FT_LEB, + FT_BoundaryAlign, FT_SymbolId, FT_CVInlineLines, FT_CVDefRange, @@ -563,6 +565,49 @@ } }; +class MCBoundaryAlignFragment : public MCFragment { +private: + /// The size of the MCBoundaryAlignFragment. + /// Note: The size is lazily set during relaxation, and is not meaningful + /// before that. + uint64_t Size = 0; + /// The alignment requirement of the branch to be aligned. + Align AlignBoundary; + /// Flag to indicate whether the branch is fused. + bool Fused : 1; + /// Flag to indicate whether NOPs should be emitted. + bool EmitNops : 1; + +public: + MCBoundaryAlignFragment(Align AlignBoundary, bool Fused = false, + bool EmitNops = false, MCSection *Sec = nullptr) + : MCFragment(FT_BoundaryAlign, false, Sec), AlignBoundary(AlignBoundary), + Fused(Fused), EmitNops(EmitNops) {} + + /// \name Accessors + /// @{ + + Align getAlignment() const { return AlignBoundary; } + + uint64_t getSize() const { return Size; } + + bool canEmitNops() const { return EmitNops; } + + bool isFused() const { return Fused; } + + void setFused(bool Value) { Fused = Value; } + + void setEmitNops(bool Value) { EmitNops = Value; } + + void setSize(uint64_t Value) { Size = Value; } + + /// @} + // + + static bool classof(const MCFragment *F) { + return F->getKind() == MCFragment::FT_BoundaryAlign; + } +}; } // end namespace llvm #endif // LLVM_MC_MCFRAGMENT_H Index: llvm/include/llvm/MC/MCAssembler.h =================================================================== --- llvm/include/llvm/MC/MCAssembler.h +++ llvm/include/llvm/MC/MCAssembler.h @@ -191,9 +191,8 @@ bool layoutSectionOnce(MCAsmLayout &Layout, MCSection &Sec); bool relaxInstruction(MCAsmLayout &Layout, MCRelaxableFragment &IF); - bool relaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF); - + bool relaxBoundaryAlign(MCAsmLayout &Layout, MCBoundaryAlignFragment &BF); bool relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF); bool relaxDwarfCallFrameFragment(MCAsmLayout &Layout, MCDwarfCallFrameFragment &DF); Index: llvm/include/llvm/MC/MCAsmBackend.h =================================================================== --- llvm/include/llvm/MC/MCAsmBackend.h +++ llvm/include/llvm/MC/MCAsmBackend.h @@ -46,6 +46,9 @@ const support::endianness Endian; + virtual void alignBranchesBegin(MCObjectStreamer &OS, const MCInst &Inst) {} + virtual void alignBranchesEnd(MCObjectStreamer &OS, const MCInst &Inst) {} + /// lifetime management virtual void reset() {}
_______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits