https://github.com/ColinKinloch updated https://github.com/llvm/llvm-project/pull/168632
>From 925247bfe6d85fab1cdb7c4f4092fe5f47033776 Mon Sep 17 00:00:00 2001 From: Colin Kinloch <[email protected]> Date: Tue, 18 Nov 2025 23:28:43 +0000 Subject: [PATCH 1/2] [StaticAnalyzer] Fix non decimal macro values in tryExpandAsInteger Values were parsed into an unsigned APInt with just enough of a bit width to hold the number then interpreted as signed values. This resulted in hex, octal and binary literals from being interpreted as negative when the most significant bit is 1. For example the `-0b11` would have a bit width of 2, would be interpreted as -1, then negated to become 1. --- clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp | 14 ++++++++++---- .../Analysis/std-c-library-functions-eof-2-rad.c | 16 ++++++++++++++++ 2 files changed, 26 insertions(+), 4 deletions(-) create mode 100644 clang/test/Analysis/std-c-library-functions-eof-2-rad.c diff --git a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp index 8b404377186e9..9cf31af37f116 100644 --- a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp +++ b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp @@ -142,19 +142,25 @@ std::optional<int> tryExpandAsInteger(StringRef Macro, const Preprocessor &PP) { if (InvalidSpelling) return std::nullopt; - llvm::APInt IntValue; + llvm::APSInt IntValue(0, true); constexpr unsigned AutoSenseRadix = 0; - if (ValueStr.getAsInteger(AutoSenseRadix, IntValue)) + if (ValueStr.getAsInteger(AutoSenseRadix, + static_cast<llvm::APInt &>(IntValue))) return std::nullopt; // Parse an optional minus sign. size_t Size = FilteredTokens.size(); if (Size >= 2) { - if (FilteredTokens[Size - 2].is(tok::minus)) + if (FilteredTokens[Size - 2].is(tok::minus)) { + // Make sure there's space for a sign bit + if (IntValue.isSignBitSet()) + IntValue = IntValue.extend(IntValue.getBitWidth() + 1); + IntValue.setIsUnsigned(false); IntValue = -IntValue; + } } - return IntValue.getSExtValue(); + return IntValue.getExtValue(); } OperatorKind operationKindFromOverloadedOperator(OverloadedOperatorKind OOK, diff --git a/clang/test/Analysis/std-c-library-functions-eof-2-rad.c b/clang/test/Analysis/std-c-library-functions-eof-2-rad.c new file mode 100644 index 0000000000000..6ead28b97fbf7 --- /dev/null +++ b/clang/test/Analysis/std-c-library-functions-eof-2-rad.c @@ -0,0 +1,16 @@ +// RUN: %clang_analyze_cc1 -std=c23 -analyzer-checker=core,unix.StdCLibraryFunctions,debug.ExprInspection -verify -analyzer-config eagerly-assume=false %s + +void clang_analyzer_eval(int); + +typedef struct FILE FILE; +/// Test that the static analyzer doesn't interpret the most significant bit as the sign bit. +// Unorthodox EOF value with a power of 2 radix +#define EOF (-0b11) + +int getc(FILE *); +void test_getc(FILE *fp) { + int y = getc(fp); + if (y < 0) { + clang_analyzer_eval(y == EOF); // expected-warning{{TRUE}} + } +} >From 93f6307abbde106ea4eff217499dc27457ba6254 Mon Sep 17 00:00:00 2001 From: Colin Kinloch <[email protected]> Date: Mon, 24 Nov 2025 18:48:45 +0000 Subject: [PATCH 2/2] Comment arguments for APSInt constructor --- clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp index 9cf31af37f116..29d55ac1cd84b 100644 --- a/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp +++ b/clang/lib/StaticAnalyzer/Core/CheckerHelpers.cpp @@ -142,7 +142,7 @@ std::optional<int> tryExpandAsInteger(StringRef Macro, const Preprocessor &PP) { if (InvalidSpelling) return std::nullopt; - llvm::APSInt IntValue(0, true); + llvm::APSInt IntValue(/*BitWidth=*/0, /*isUnsigned=*/true); constexpr unsigned AutoSenseRadix = 0; if (ValueStr.getAsInteger(AutoSenseRadix, static_cast<llvm::APInt &>(IntValue))) _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
