Parse error when propagating constant float point fields loaded from class files

Issue #224 resolved
Olivier Hamel created an issue

(Sequel to issue #223.)

Issue: Exactly what the title says.


float f = Double.NEGATIVE_INFINITY;

Const-expr-ness will propagate from Double.NEGATIVE_INFINITY, which will lead to an attempt to parse "Infinity". This constant occurs b/c Double was loaded from a class file; the literal's token was synthesised from the bytecode by toStringing the F64 value.

Same suggested fix as #223. The expanded domain of <F32/F64>.constant() shouldn't be externally visible, so long as the lexer/parser rejects 'Infinity' as a float literal.

PS: Suggested fix doesn't handle various flavours of NaN.

PPS: Might be worth checking out if Java's toString of floating-point types is guaranteed to round-trip through parseFloat/Double for finite values. Disappointingly, this doesn't tend to be true for most formatters...

Comments (5)

  1. Jesper Öqvist

    Can you provide a minimal example that produces the parse error? The demonstrator you gave does not cause a parse error when inserted as a local variable.

  2. Olivier Hamel reporter

    This is effectively resolved by the fix for #223, which avoids the round-trip-through-string dance.

    Ignoring the minor typo in the sample (float instead of double), I'm uncertain as to why the demonstrator did not provoke the issue for you. It does in our build, but we're running a slightly modified version of extendj with a few quick hacky hot-fixes that's spliced onto the front of Soot. It could be our jimple backend that's causing the issue to manifest, pardon...

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