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| author | Fangrui Song <maskray@google.com> | 2020-01-13 10:34:10 -0800 |
|---|---|---|
| committer | Fangrui Song <maskray@google.com> | 2020-01-13 10:42:21 -0800 |
| commit | 64a93afc3c630c39e5c583e4f67aef5821d635b6 (patch) | |
| tree | c5a68796c0cabeea934fddd88306e4c9d19a8234 /llvm/unittests/MC/Disassembler.cpp | |
| parent | 484a7472f1aa6906f2b66dc33bcf69cc8d5b9f29 (diff) | |
| download | bcm5719-llvm-64a93afc3c630c39e5c583e4f67aef5821d635b6.tar.gz bcm5719-llvm-64a93afc3c630c39e5c583e4f67aef5821d635b6.zip | |
[X86][Disassembler] Fix a bug when disassembling an empty string
readPrefixes() assumes insn->bytes is non-empty. The code path is not
exercised in llvm-mc because llvm-mc does not feed empty input to
MCDisassembler::getInstruction().
This bug is uncovered by a5994c789a2982a770254ae1607b5b4cb641f73c.
An empty string did not crash before because the deleted regionReader()
allowed UINT64_C(-1) as insn->readerCursor.
Bytes.size() <= Address -> R->Base
0 <= UINT64_C(-1) - UINT32_C(-1)
Diffstat (limited to 'llvm/unittests/MC/Disassembler.cpp')
| -rw-r--r-- | llvm/unittests/MC/Disassembler.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/unittests/MC/Disassembler.cpp b/llvm/unittests/MC/Disassembler.cpp index cdb344474ca..3f9e6e5501e 100644 --- a/llvm/unittests/MC/Disassembler.cpp +++ b/llvm/unittests/MC/Disassembler.cpp @@ -38,6 +38,10 @@ TEST(Disassembler, X86Test) { unsigned NumBytes = sizeof(Bytes); unsigned PC = 0; + InstSize = + LLVMDisasmInstruction(DCR, BytesP, 0, PC, OutString, OutStringSize); + EXPECT_EQ(InstSize, 0U); + InstSize = LLVMDisasmInstruction(DCR, BytesP, NumBytes, PC, OutString, OutStringSize); EXPECT_EQ(InstSize, 1U); |
