e6bf48d110
As of revea222be0d, LLVMs assembler will actually try to honour the "fill value" part of p2align directives. X86 printed these as 0x90, which isn't actually what it wanted: we want multi-byte nops for .text padding. Compiling via a textual assembly file produces single-byte nop padding sinceea222be0dbut the built-in assembler will produce multi-byte nops. This divergent behaviour is undesirable. To fix: don't set the byte padding field for x86, which allows the assembler to pick multi-byte nops. Test that we get the same multi-byte padding when compiled via textual assembly or directly to object file. Added same-align-bytes-with-llasm-llobj.ll to that effect, updated numerous other tests to not contain check-lines for the explicit padding.
137 lines
3.3 KiB
YAML
137 lines
3.3 KiB
YAML
# Check if the alignment directive is put on the correct place when the basic block section option is used.
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# RUN: llc -mtriple x86_64-unknown-linux-gnu -start-after=bbsections-prepare %s -o - | FileCheck %s -check-prefix=CHECK
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# How to generate the input:
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# foo.c
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# int test(int a) {
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# switch (a) {
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# default:
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# return 10;
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# case 1:
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# a += 1;
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# case 2:
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# a *= -1;
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# case 8:
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# break;
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# }
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# return a;
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# }
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#
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# clang -O0 -S -emit-llvm test.c
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# llc < test.ll -stop-after=bbsections-prepare -align-all-nofallthru-blocks=8 -basic-block-sections=all
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--- |
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define i32 @test(i32 noundef %a) {
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entry:
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switch i32 %a, label %return [
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i32 1, label %sw.bb1
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i32 2, label %sw.bb1
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i32 8, label %sw.epilog
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]
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sw.bb1: ; preds = %entry, %entry
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br label %sw.epilog
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sw.epilog: ; preds = %sw.bb1, %entry
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%a.addr.1 = phi i32 [ %a, %entry ], [ -2, %sw.bb1 ]
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br label %return
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return: ; preds = %sw.epilog, %entry
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%retval.0 = phi i32 [ %a.addr.1, %sw.epilog ], [ 10, %entry ]
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ret i32 %retval.0
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}
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...
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---
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name: test
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alignment: 16
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exposesReturnsTwice: false
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legalized: false
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regBankSelected: false
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selected: false
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failedISel: false
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tracksRegLiveness: true
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hasWinCFI: false
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callsEHReturn: false
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callsUnwindInit: false
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hasEHCatchret: false
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hasEHScopes: false
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hasEHFunclets: false
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failsVerification: false
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tracksDebugUserValues: true
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registers: []
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liveins:
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- { reg: '$edi', virtual-reg: '' }
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frameInfo:
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isFrameAddressTaken: false
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isReturnAddressTaken: false
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hasStackMap: false
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hasPatchPoint: false
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stackSize: 0
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offsetAdjustment: 0
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maxAlignment: 1
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adjustsStack: false
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hasCalls: false
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stackProtector: ''
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functionContext: ''
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maxCallFrameSize: 0
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cvBytesOfCalleeSavedRegisters: 0
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hasOpaqueSPAdjustment: false
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hasVAStart: false
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hasMustTailInVarArgFunc: false
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hasTailCall: false
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localFrameSize: 0
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savePoint: ''
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restorePoint: ''
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fixedStack: []
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stack: []
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callSites: []
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debugValueSubstitutions: []
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constants: []
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machineFunctionInfo: {}
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body: |
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bb.0.entry:
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successors: %bb.1(0x40000000), %bb.2(0x40000000)
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liveins: $edi
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renamable $edi = KILL $edi, implicit-def $rdi
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renamable $eax = LEA64_32r renamable $rdi, 1, $noreg, -1, $noreg
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CMP32ri8 killed renamable $eax, 2, implicit-def $eflags
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JCC_1 %bb.2, 3, implicit $eflags
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JMP_1 %bb.1
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bb.1.sw.bb1 (bbsections 1):
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successors: %bb.3(0x80000000)
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renamable $edi = MOV32ri -2, implicit-def $rdi
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JMP_1 %bb.3
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bb.2.entry (align 256, bbsections 2):
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successors: %bb.3(0x40000000), %bb.4(0x40000000)
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liveins: $rdi
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renamable $eax = MOV32ri 10
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CMP32ri8 renamable $edi, 8, implicit-def $eflags
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JCC_1 %bb.4, 5, implicit $eflags
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JMP_1 %bb.3
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bb.3.sw.epilog (bbsections 3):
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successors: %bb.4(0x80000000)
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liveins: $rdi
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$eax = MOV32rr $edi, implicit killed $rdi
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JMP_1 %bb.4
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bb.4.return (bbsections 4):
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liveins: $eax
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RET64 $eax
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...
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# CHECK: .section .text.test,"ax",@progbits,unique,2
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# CHECK-NEXT: .p2align 8
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# CHECK-NEXT: test.__part.2: # %entry
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