forked from OSchip/llvm-project
[BOLT] Tail Duplication: skip unreachable blocks
Summary: TailDuplication::isInCacheLine makes the assumption that the block has a valid layout index, which is not the case for unreachable blocks. Add a check for a valid layout index. (cherry picked from FBD32659755)
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@ -387,6 +387,10 @@ void TailDuplication::runOnFunction(BinaryFunction &Function) {
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if (BB->hasJumpTable())
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continue;
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// Skip not-in-layout, i.e. unreachable, blocks.
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if (BB->getLayoutIndex() >= BlockLayout.size())
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continue;
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// and we are estimating that this sucessor is not already in the same cache
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// line
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BinaryBasicBlock *Succ = BB->getSuccessor();
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@ -0,0 +1,31 @@
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# This reproduces a bug in TailDuplication::isInCacheLine
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# with accessing BlockLayout past bounds (unreachable blocks).
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# REQUIRES: system-linux
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# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
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# RUN: %s -o %t.o
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# RUN: link_fdata %s %t.o %t.fdata
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# RUN: llvm-strip --strip-unneeded %t.o
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# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q -nostdlib
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# RUN: llvm-bolt %t.exe -o %t.out -data %t.fdata -relocs \
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# RUN: -tail-duplication=1 -tail-duplication-aggressive=1
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.globl _start
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_start:
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jmp d
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je _start
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movl %esi, %edi
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d:
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jmpq *JT0(,%rcx,8)
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# FDATA: 1 _start #d# 1 _start #e# 1 3
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f:
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movl 0, %esi
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g:
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movl 0, %esi
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e:
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jmp f
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.rodata
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JT0:
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.quad g
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.quad e
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