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160798ab9b
Make the SimpleSValBuilder to be able to look up and use a constraint for an operand of a SymbolCast, when the operand is constrained to a const value. This part of the SValBuilder is responsible for constant folding. We need this constant folding, so the engine can work with less symbols, this way it can be more efficient. Whenever a symbol is constrained with a constant then we substitute the symbol with the corresponding integer. If a symbol is constrained with a range, then the symbol is kept and we fall-back to use the range based constraint manager, which is not that efficient. This patch is the natural extension of the existing constant folding machinery with the support of SymbolCast symbols. Differential Revision: https://reviews.llvm.org/D126481
59 lines
2.3 KiB
C++
59 lines
2.3 KiB
C++
// RUN: %clang_analyze_cc1 %s \
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// RUN: -analyzer-checker=core \
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// RUN: -analyzer-checker=debug.ExprInspection \
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// RUN: -analyzer-config support-symbolic-integer-casts=true \
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// RUN: -analyzer-config eagerly-assume=false \
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// RUN: -triple x86_64-unknown-linux-gnu \
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// RUN: -verify
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// Test that the SValBuilder is able to look up and use a constraint for an
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// operand of a SymbolCast, when the operand is constrained to a const value.
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void clang_analyzer_eval(bool);
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extern void abort() __attribute__((__noreturn__));
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#define assert(expr) ((expr) ? (void)(0) : abort())
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void test(int x) {
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// Constrain a SymSymExpr to a constant value.
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assert(x * x == 1);
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// It is expected to be able to get the constraint for the operand of the
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// cast.
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clang_analyzer_eval((char)(x * x) == 1); // expected-warning{{TRUE}}
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clang_analyzer_eval((long)(x * x) == 1); // expected-warning{{TRUE}}
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}
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void test1(int x, int y) {
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// Even if two lower bytes of `x` equal to zero, it doesn't mean that
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// the entire `x` is zero. We are not able to know the exact value of x.
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// It can be one of 65536 possible values like
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// [0, 65536, -65536, 131072, -131072, ...]. To avoid huge range sets we
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// still assume `x` in the range [INT_MIN, INT_MAX].
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assert((short)x == 0); // Lower two bytes are set to 0.
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static_assert((short)65536 == 0, "");
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static_assert((short)-65536 == 0, "");
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static_assert((short)131072 == 0, "");
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static_assert((short)-131072 == 0, "");
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clang_analyzer_eval(x == 0); // expected-warning{{UNKNOWN}}
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// These are not truncated to short as zero.
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static_assert((short)1 != 0, "");
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clang_analyzer_eval(x == 1); // expected-warning{{FALSE}}
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static_assert((short)-1 != 0, "");
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clang_analyzer_eval(x == -1); // expected-warning{{FALSE}}
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static_assert((short)65537 != 0, "");
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clang_analyzer_eval(x == 65537); // expected-warning{{FALSE}}
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static_assert((short)-65537 != 0, "");
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clang_analyzer_eval(x == -65537); // expected-warning{{FALSE}}
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static_assert((short)131073 != 0, "");
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clang_analyzer_eval(x == 131073); // expected-warning{{FALSE}}
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static_assert((short)-131073 != 0, "");
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clang_analyzer_eval(x == -131073); // expected-warning{{FALSE}}
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// Check for implicit cast.
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short s = y;
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assert(s == 0);
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clang_analyzer_eval(y == 0); // expected-warning{{UNKNOWN}}
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}
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