[clang] [clang][analyzer] Add missing stream related functions to StdLibraryFunctionsChecker. (PR #76979)

[Balázs Kéri via cfe-commits]

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@@ -2201,6 +2214,56 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
                   ErrnoNEZeroIrrelevant, GenericFailureMsg)
             .ArgConstraint(NotNull(ArgNo(0))));
 
+    // int fgetc(FILE *stream);
+    // 'getc' is the same as 'fgetc' but may be a macro
+    addToFunctionSummaryMap(
+        {"getc", "fgetc"}, Signature(ArgTypes{FilePtrTy}, RetType{IntTy}),
+        Summary(NoEvalCall)
+            .Case({ReturnValueCondition(WithinRange, {{0, UCharRangeMax}})},
+                  ErrnoMustNotBeChecked, GenericSuccessMsg)
+            .Case({ReturnValueCondition(WithinRange, SingleValue(EOFv))},
+                  ErrnoNEZeroIrrelevant, GenericFailureMsg)
+            .ArgConstraint(NotNull(ArgNo(0))));
+
+    // int fputc(int c, FILE *stream);
+    // 'putc' is the same as 'fputc' but may be a macro
+    addToFunctionSummaryMap(
+        {"putc", "fputc"},
+        Signature(ArgTypes{IntTy, FilePtrTy}, RetType{IntTy}),
+        Summary(NoEvalCall)
+            .Case({ReturnValueCondition(BO_EQ, ArgNo(0))},
+                  ErrnoMustNotBeChecked, GenericSuccessMsg)
+            .Case({ReturnValueCondition(WithinRange, SingleValue(EOFv))},
+                  ErrnoNEZeroIrrelevant, GenericFailureMsg)
+            .ArgConstraint(NotNull(ArgNo(1)))
+            .ArgConstraint(
+                ArgumentCondition(0, WithinRange, {{0, UCharRangeMax}})));
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balazske wrote:

Is it better to allow the range of any integer, and restrict only the return value to unsigned char range? (According to documentation the value is converted to `unsigned char` before write.)

https://github.com/llvm/llvm-project/pull/76979