[clang] df1f4e0 - Revert "[analyzer] Ignore IncompleteArrayTypes in getStaticSize() for FAMs"

[Balazs Benics via cfe-commits]

Author: Balazs Benics
Date: 2021-08-25T16:43:25+02:00
New Revision: df1f4e0cc6ec9a734aae41ffd48ee8b2007fcabb

URL: https://github.com/llvm/llvm-project/commit/df1f4e0cc6ec9a734aae41ffd48ee8b2007fcabb
DIFF: https://github.com/llvm/llvm-project/commit/df1f4e0cc6ec9a734aae41ffd48ee8b2007fcabb.diff

LOG: Revert "[analyzer] Ignore IncompleteArrayTypes in getStaticSize() for FAMs"

This reverts commit 360ced3b8fd2cfb9f2a26deb739e6c381e98b9a5.

Added: 
    

Modified: 
    clang/lib/StaticAnalyzer/Core/MemRegion.cpp

Removed: 
    clang/test/Analysis/flexible-array-members.c


################################################################################
diff  --git a/clang/lib/StaticAnalyzer/Core/MemRegion.cpp b/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
index 1a614d4d2bcd..bd725ee9eaa3 100644
--- a/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ b/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -768,27 +768,14 @@ DefinedOrUnknownSVal MemRegionManager::getStaticSize(const MemRegion *MR,
       return UnknownVal();
 
     QualType Ty = cast<TypedValueRegion>(SR)->getDesugaredValueType(Ctx);
-    const DefinedOrUnknownSVal Size = getElementExtent(Ty, SVB);
+    DefinedOrUnknownSVal Size = getElementExtent(Ty, SVB);
 
     // A zero-length array at the end of a struct often stands for dynamically
     // allocated extra memory.
-    const auto isFlexibleArrayMemberCandidate = [this](QualType Ty) -> bool {
-      const ArrayType *AT = Ctx.getAsArrayType(Ty);
-      if (!AT)
-        return false;
-      if (isa<IncompleteArrayType>(AT))
-        return true;
-
-      if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
-        const llvm::APInt &Size = CAT->getSize();
-        if (Size.isNullValue())
-          return true;
-      }
-      return false;
-    };
-
-    if (isFlexibleArrayMemberCandidate(Ty))
-      return UnknownVal();
+    if (Size.isZeroConstant()) {
+      if (isa<ConstantArrayType>(Ty))
+        return UnknownVal();
+    }
 
     return Size;
   }

diff  --git a/clang/test/Analysis/flexible-array-members.c b/clang/test/Analysis/flexible-array-members.c
deleted file mode 100644
index 23a8d1fde0d9..000000000000
--- a/clang/test/Analysis/flexible-array-members.c
+++ /dev/null
@@ -1,96 +0,0 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c90
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c99
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c11
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c17
-
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++98 -x c++
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++03 -x c++
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++11 -x c++
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++14 -x c++
-// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix,debug.ExprInspection %s -verify -std=c++17 -x c++
-
-typedef __typeof(sizeof(int)) size_t;
-size_t clang_analyzer_getExtent(void *);
-void clang_analyzer_dump(size_t);
-
-void *alloca(size_t size);
-void *malloc(size_t size);
-void free(void *ptr);
-
-void test_incomplete_array_fam() {
-  typedef struct FAM {
-    char c;
-    int data[];
-  } FAM;
-
-  FAM fam;
-  clang_analyzer_dump(clang_analyzer_getExtent(&fam));
-  clang_analyzer_dump(clang_analyzer_getExtent(fam.data));
-  // expected-warning at -2 {{4 S64b}}
-  // expected-warning at -2 {{Unknown}}
-
-  FAM *p = (FAM *)alloca(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(p));
-  clang_analyzer_dump(clang_analyzer_getExtent(p->data));
-  // expected-warning at -2 {{4 U64b}}
-  // expected-warning at -2 {{Unknown}}
-
-  FAM *q = (FAM *)malloc(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(q));
-  clang_analyzer_dump(clang_analyzer_getExtent(q->data));
-  // expected-warning at -2 {{4 U64b}}
-  // expected-warning at -2 {{Unknown}}
-  free(q);
-}
-
-void test_zero_length_array_fam() {
-  typedef struct FAM {
-    char c;
-    int data[0];
-  } FAM;
-
-  FAM fam;
-  clang_analyzer_dump(clang_analyzer_getExtent(&fam));
-  clang_analyzer_dump(clang_analyzer_getExtent(fam.data));
-  // expected-warning at -2 {{4 S64b}}
-  // expected-warning at -2 {{Unknown}}
-
-  FAM *p = (FAM *)alloca(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(p));
-  clang_analyzer_dump(clang_analyzer_getExtent(p->data));
-  // expected-warning at -2 {{4 U64b}}
-  // expected-warning at -2 {{Unknown}}
-
-  FAM *q = (FAM *)malloc(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(q));
-  clang_analyzer_dump(clang_analyzer_getExtent(q->data));
-  // expected-warning at -2 {{4 U64b}}
-  // expected-warning at -2 {{Unknown}}
-  free(q);
-}
-
-void test_single_element_array_possible_fam() {
-  typedef struct FAM {
-    char c;
-    int data[1];
-  } FAM;
-
-  FAM likely_fam;
-  clang_analyzer_dump(clang_analyzer_getExtent(&likely_fam));
-  clang_analyzer_dump(clang_analyzer_getExtent(likely_fam.data));
-  // expected-warning at -2 {{8 S64b}}
-  // expected-warning at -2 {{4 S64b}}
-
-  FAM *p = (FAM *)alloca(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(p));
-  clang_analyzer_dump(clang_analyzer_getExtent(p->data));
-  // expected-warning at -2 {{8 U64b}}
-  // expected-warning at -2 {{4 S64b}}
-
-  FAM *q = (FAM *)malloc(sizeof(FAM));
-  clang_analyzer_dump(clang_analyzer_getExtent(q));
-  clang_analyzer_dump(clang_analyzer_getExtent(q->data));
-  // expected-warning at -2 {{8 U64b}}
-  // expected-warning at -2 {{4 S64b}}
-  free(q);
-}