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Differential D5029

[Support] fix the ULEB128 decoding bug.
ClosedPublic

Authored by arphaman on Aug 22 2014, 9:30 AM.

Details

Reviewers
bob.wilson
bogner
dexonsmith
Commits
rG5117674f55a7: [Support] Fix the overflow bug in ULEB128 decoding.
rL216268: [Support] Fix the overflow bug in ULEB128 decoding.
Summary

This patch fixes the ULEB128 decoding which currently overflows when evaluating (*p & 0x7f) << Shift were *p = 0x10 and Shift is 28.

Diff Detail

Event Timeline

arphaman updated this revision to Diff 12845.Aug 22 2014, 9:30 AM
arphaman retitled this revision from to [Support] fix the ULEB128 decoding bug..
arphaman updated this object.
arphaman edited the test plan for this revision. (Show Details)
arphaman added reviewers: bob.wilson, bogner, dexonsmith.
arphaman set the repository for this revision to rL LLVM.
arphaman added a subscriber: Unknown Object (MLST).
dexonsmith edited edge metadata.Aug 22 2014, 9:33 AM

Ouch. LGTM!

arphaman closed this revision.Aug 22 2014, 9:39 AM
arphaman updated this revision to Diff 12846.

Closed by commit rL216268 (authored by @arphaman).

Revision Contents

PathSize
include/
llvm/
Support/
2 lines
unittests/
Support/
1 line

Diff 12845

include/llvm/Support/LEB128.h

Context not available.
uint64_t Value = 0; uint64_t Value = 0;
unsigned Shift = 0; unsigned Shift = 0;
do { do {
Value += (*p & 0x7f) << Shift; Value += uint64_t(*p & 0x7f) << Shift;
Shift += 7; Shift += 7;
} while (*p++ >= 128); } while (*p++ >= 128);
if (n) if (n)
Context not available.

unittests/Support/LEB128Test.cpp

Context not available.
EXPECT_DECODE_ULEB128_EQ(0xffu, "\xff\x01"); EXPECT_DECODE_ULEB128_EQ(0xffu, "\xff\x01");
EXPECT_DECODE_ULEB128_EQ(0x100u, "\x80\x02"); EXPECT_DECODE_ULEB128_EQ(0x100u, "\x80\x02");
EXPECT_DECODE_ULEB128_EQ(0x101u, "\x81\x02"); EXPECT_DECODE_ULEB128_EQ(0x101u, "\x81\x02");
EXPECT_DECODE_ULEB128_EQ(4294975616ULL, "\x80\xc1\x80\x80\x10");
// Decode ULEB128 with extra padding bytes // Decode ULEB128 with extra padding bytes
EXPECT_DECODE_ULEB128_EQ(0u, "\x80\x00"); EXPECT_DECODE_ULEB128_EQ(0u, "\x80\x00");
Context not available.