[clang] [clang] [Static analyzer]: add initial support for builtin overflow (PR #102602)

[Donát Nagy via cfe-commits]

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@@ -21,16 +21,67 @@
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerHelpers.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicExtent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
 
 using namespace clang;
 using namespace ento;
 
 namespace {
 
+QualType getOverflowBuiltinResultType(const CallEvent &Call) {
+  assert(Call.getNumArgs() == 3);
+
+  return Call.getArgExpr(2)->getType()->getPointeeType();
+}
+
+QualType getOverflowBuiltinResultType(const CallEvent &Call, CheckerContext &C,
+                                      unsigned BI) {
+  assert(Call.getNumArgs() == 3);
+
+  ASTContext &Ast = C.getASTContext();
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NagyDonat wrote:

`<bikeshedding>`
Checker code usually uses the name `ACtx` for 'the' `ASTContext` object, so consider using that here. However, `Ast` is also a completely correct name, so if you prefer it, feel free to keep it.
`</bikeshedding>`

https://github.com/llvm/llvm-project/pull/102602