Commit 2e90d3af authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r292949: 

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r292949 | rnk | 2017-01-24 08:57:55 -0800 (Tue, 24 Jan 2017) | 6 lines

[CodeView] Fix off-by-one error in def range gap emission

Also fixes a much worse bug where we emitted the wrong gap size for the
def range uncovered by the test for this issue.

Fixes PR31726.
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llvm-svn: 294479
parent 914f2d0d

llvm/lib/MC/MCCodeView.cpp

+6 −6
Original line number Diff line number Diff line
@@ -509,17 +509,17 @@ void CodeViewContext::encodeDefRange(MCAsmLayout &Layout, 
      // are artificially constructing.

      size_t RecordSize = FixedSizePortion.size() +

                          sizeof(LocalVariableAddrRange) + 4 * NumGaps;

      // Write out the recrod size.

      support::endian::Writer<support::little>(OS).write<uint16_t>(RecordSize);

      // Write out the record size.

      LEWriter.write<uint16_t>(RecordSize);

      // Write out the fixed size prefix.

      OS << FixedSizePortion;

      // Make space for a fixup that will eventually have a section relative

      // relocation pointing at the offset where the variable becomes live.

      Fixups.push_back(MCFixup::create(Contents.size(), BE, FK_SecRel_4));

      Contents.resize(Contents.size() + 4); // Fixup for code start.

      LEWriter.write<uint32_t>(0); // Fixup for code start.

      // Make space for a fixup that will record the section index for the code.

      Fixups.push_back(MCFixup::create(Contents.size(), BE, FK_SecRel_2));

      Contents.resize(Contents.size() + 2); // Fixup for section index.

      LEWriter.write<uint16_t>(0); // Fixup for section index.

      // Write down the range's extent.

      LEWriter.write<uint16_t>(Chunk);
@@ -529,7 +529,7 @@ void CodeViewContext::encodeDefRange(MCAsmLayout &Layout, 
    } while (RangeSize > 0);



    // Emit the gaps afterwards.

    assert((NumGaps == 0 || Bias < MaxDefRange) &&

    assert((NumGaps == 0 || Bias <= MaxDefRange) &&

           "large ranges should not have gaps");

    unsigned GapStartOffset = GapAndRangeSizes[I].second;

    for (++I; I != J; ++I) {
@@ -537,7 +537,7 @@ void CodeViewContext::encodeDefRange(MCAsmLayout &Layout, 
      assert(I < GapAndRangeSizes.size());

      std::tie(GapSize, RangeSize) = GapAndRangeSizes[I];

      LEWriter.write<uint16_t>(GapStartOffset);

      LEWriter.write<uint16_t>(RangeSize);

      LEWriter.write<uint16_t>(GapSize);

      GapStartOffset += GapSize + RangeSize;

    }

  }

llvm/test/MC/COFF/cv-def-range-gap.s

+24 −0
Original line number Diff line number Diff line
@@ -37,6 +37,19 @@ 
# CHECK-NEXT:        ISectStart: 0x0

# CHECK-NEXT:        Range: 0x1

# CHECK-NEXT:      }

# CHECK-NEXT:    }

# CHECK-NEXT:    DefRangeRegister {

# CHECK-NEXT:      Register: 23

# CHECK-NEXT:      MayHaveNoName: 0

# CHECK-NEXT:      LocalVariableAddrRange {

# CHECK-NEXT:        OffsetStart: .text+0x2001C

# CHECK-NEXT:        ISectStart: 0x0

# CHECK-NEXT:        Range: 0xF000

# CHECK-NEXT:      }

# CHECK-NEXT:      LocalVariableAddrGap [

# CHECK-NEXT:        GapStartOffset: 0x1

# CHECK-NEXT:        Range: 0xEFFE

# CHECK-NEXT:      ]

# CHECK-NEXT:    }



	.text
@@ -62,6 +75,16 @@ f: # @f 
.Lbegin3:

	nop

.Lend3:



	# Create a range that is exactly 0xF000 bytes long with a gap in the

	# middle.

.Lbegin4:

	nop

.Lend4:

	.fill 0xeffe, 1, 0x90

.Lbegin5:

	nop

.Lend5:

	ret

.Lfunc_end0:
@@ -94,6 +117,7 @@ f: # @f 
	.asciz	"p"

.Ltmp19:

	.cv_def_range	 .Lbegin0 .Lend0 .Lbegin1 .Lend1 .Lbegin2 .Lend2 .Lbegin3 .Lend3, "A\021\027\000\000\000"

	.cv_def_range	 .Lbegin4 .Lend4 .Lbegin5 .Lend5, "A\021\027\000\000\000"

	.short	2                       # Record length

	.short	4431                    # Record kind: S_PROC_ID_END

.Ltmp15: