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C++/C#: Fix bad overlap sanity failures

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`Instruction.getDefinitionOverlap()` depends on `SSAConstruction::getMemoryOperandDefinition()`, which in turn depends on `SSAConstruction::hasMemoryOperandDefinition()`. When the definition in question came from a `Chi` instruction, `hasMemoryOperandDefinition()` incorrectly bound `overlap` to the overlap relationship between the original (non-`Chi`) instruction and the use. The fix is to make use of the `actualDefLocation` parameter to `getDefinitionOrChiInstruction()`, which specifies the location for the result of the `Chi` in that case.
This commit is contained in:
Dave Bartolomeo
2020-03-23 14:57:41 -04:00
parent a2741da8e2
commit c5ac357bfc
12 changed files with 20 additions and 685 deletions
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7
csharp/ql/src/semmle/code/csharp/ir/implementation/unaliased_ssa/internal/SSAConstruction.qll
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@@ -84,14 +84,15 @@ private module Cached {
oldOperand instanceof OldIR::NonPhiMemoryOperand and
exists(
OldBlock useBlock, int useRank, Alias::MemoryLocation useLocation,
Alias::MemoryLocation defLocation, OldBlock defBlock, int defRank, int defOffset
Alias::MemoryLocation defLocation, OldBlock defBlock, int defRank, int defOffset,
Alias::MemoryLocation actualDefLocation
|
useLocation = Alias::getOperandMemoryLocation(oldOperand) and
hasUseAtRank(useLocation, useBlock, useRank, oldInstruction) and
definitionReachesUse(useLocation, defBlock, defRank, useBlock, useRank) and
hasDefinitionAtRank(useLocation, defLocation, defBlock, defRank, defOffset) and
instr = getDefinitionOrChiInstruction(defBlock, defOffset, defLocation, _) and
overlap = Alias::getOverlap(defLocation, useLocation)
instr = getDefinitionOrChiInstruction(defBlock, defOffset, defLocation, actualDefLocation) and
overlap = Alias::getOverlap(actualDefLocation, useLocation)
)
}