[clang] b7f986d - [clang][analyzer] Improve modeling of 'execv' and 'execvp' in StdLibraryFunctionsChecker (#78930)

[via cfe-commits]

Author: Ben Shi
Date: 2024-01-25T09:23:40+08:00
New Revision: b7f986d987edd50f8b16ae90d38358b01f0272ac

URL: https://github.com/llvm/llvm-project/commit/b7f986d987edd50f8b16ae90d38358b01f0272ac
DIFF: https://github.com/llvm/llvm-project/commit/b7f986d987edd50f8b16ae90d38358b01f0272ac.diff

LOG: [clang][analyzer] Improve modeling of 'execv' and 'execvp' in StdLibraryFunctionsChecker (#78930)

These functions always return -1 and set 'errno'.

Added: 
    

Modified: 
    clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
    clang/test/Analysis/errno-stdlibraryfunctions.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
index fcd907a9bb0da0..61bf3c8528be2b 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StdLibraryFunctionsChecker.cpp
@@ -3002,7 +3002,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
         "execv",
         Signature(ArgTypes{ConstCharPtrTy, CharPtrConstPtr}, RetType{IntTy}),
         Summary(NoEvalCall)
-            .Case(ReturnsMinusOne, ErrnoIrrelevant)
+            .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant)
             .ArgConstraint(NotNull(ArgNo(0))));
 
     // int execvp(const char *file, char *const argv[]);
@@ -3010,7 +3010,7 @@ void StdLibraryFunctionsChecker::initFunctionSummaries(
         "execvp",
         Signature(ArgTypes{ConstCharPtrTy, CharPtrConstPtr}, RetType{IntTy}),
         Summary(NoEvalCall)
-            .Case(ReturnsMinusOne, ErrnoIrrelevant)
+            .Case(ReturnsMinusOne, ErrnoNEZeroIrrelevant)
             .ArgConstraint(NotNull(ArgNo(0))));
 
     // int getopt(int argc, char * const argv[], const char *optstring);

diff  --git a/clang/test/Analysis/errno-stdlibraryfunctions.c b/clang/test/Analysis/errno-stdlibraryfunctions.c
index 9e3d07e7aa88a0..7876bafc2eb210 100644
--- a/clang/test/Analysis/errno-stdlibraryfunctions.c
+++ b/clang/test/Analysis/errno-stdlibraryfunctions.c
@@ -89,3 +89,17 @@ void errno_getcwd(char *Buf, size_t Sz) {
     if (errno) {}                      // expected-warning{{An undefined value may be read from 'errno'}}
   }
 }
+
+void errno_execv(char *Path, char * Argv[]) {
+  int Ret = execv(Path, Argv);
+  clang_analyzer_eval(Ret == -1);  // expected-warning{{TRUE}}
+  clang_analyzer_eval(errno != 0); // expected-warning{{TRUE}}
+  if (errno) {}                    // no warning
+}
+
+void errno_execvp(char *File, char * Argv[]) {
+  int Ret = execvp(File, Argv);
+  clang_analyzer_eval(Ret == -1);  // expected-warning{{TRUE}}
+  clang_analyzer_eval(errno != 0); // expected-warning{{TRUE}}
+  if (errno) {}                    // no warning
+}