https://github.com/ziqingluo-90 updated
https://github.com/llvm/llvm-project/pull/109496
>From e7f7f82b25eaae86623ac8f47731892b3b629d7d Mon Sep 17 00:00:00 2001
From: Ziqing Luo <ziqing_...@apple.com>
Date: Fri, 20 Sep 2024 16:27:09 -0700
Subject: [PATCH] [-Wunsafe-buffer-usage] Fix a bug and suppress libc warnings
for C files
- Fix a bug in UnsafeBufferUsage.cpp related to casting to PointerType
- Suppress -Wunsafe-buffer-usage-in-libc-call for C files
(rdar://117182250)
---
clang/lib/Analysis/UnsafeBufferUsage.cpp | 8 +++++---
clang/lib/Sema/AnalysisBasedWarnings.cpp | 4 +++-
.../warn-unsafe-buffer-usage-no-libc-functions-in-c.c | 9 +++++++++
3 files changed, 17 insertions(+), 4 deletions(-)
create mode 100644
clang/test/SemaCXX/warn-unsafe-buffer-usage-no-libc-functions-in-c.c
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp
b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index a16762244b1766..110a121e71a7d2 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -250,7 +250,9 @@ AST_MATCHER_P(Stmt, ignoreUnsafeBufferInContainer,
AST_MATCHER_P(Stmt, ignoreUnsafeLibcCall, const UnsafeBufferUsageHandler *,
Handler) {
- return Handler->ignoreUnsafeBufferInLibcCall(Node.getBeginLoc());
+ if (Finder->getASTContext().getLangOpts().CPlusPlus)
+ return Handler->ignoreUnsafeBufferInLibcCall(Node.getBeginLoc());
+ return true; /* Only warn about libc calls for C++ */
}
AST_MATCHER_P(CastExpr, castSubExpr, internal::Matcher<Expr>, innerMatcher) {
@@ -789,7 +791,7 @@ AST_MATCHER_P(CallExpr, hasUnsafePrintfStringArg,
if (!FristParmTy->isPointerType())
return false; // possibly some user-defined printf function
- QualType FirstPteTy = (cast<PointerType>(FristParmTy))->getPointeeType();
+ QualType FirstPteTy = FristParmTy->getAs<PointerType>()->getPointeeType();
if (!Ctx.getFILEType()
.isNull() && //`FILE *` must be in the context if it is fprintf
@@ -865,7 +867,7 @@ AST_MATCHER(CallExpr, hasUnsafeSnprintfBuffer) {
if (!FirstParmTy->isPointerType())
return false; // Not an snprint
- QualType FirstPteTy = cast<PointerType>(FirstParmTy)->getPointeeType();
+ QualType FirstPteTy = FirstParmTy->getAs<PointerType>()->getPointeeType();
const Expr *Buf = Node.getArg(0), *Size = Node.getArg(1);
if (FirstPteTy.isConstQualified() || !Buf->getType()->isPointerType() ||
diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp
b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 117b2c8bc57935..7e0b929abea683 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -2549,6 +2549,7 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
DiagnosticOptions &DiagOpts = Diags.getDiagnosticOptions();
// UnsafeBufferUsage analysis settings.
+ bool IsCXXLang = S.getLangOpts().CPlusPlus;
bool UnsafeBufferUsageCanEmitSuggestions = S.getLangOpts().CPlusPlus20;
bool UnsafeBufferUsageShouldEmitSuggestions = // Should != Can.
UnsafeBufferUsageCanEmitSuggestions &&
@@ -2581,7 +2582,8 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
!Diags.isIgnored(diag::warn_unsafe_buffer_variable, SourceLocation()) ||
!Diags.isIgnored(diag::warn_unsafe_buffer_usage_in_container,
SourceLocation()) ||
- !Diags.isIgnored(diag::warn_unsafe_buffer_libc_call, SourceLocation())) {
+ (!Diags.isIgnored(diag::warn_unsafe_buffer_libc_call, SourceLocation())
&&
+ IsCXXLang)) {
CallableVisitor(CallAnalyzers).TraverseTranslationUnitDecl(TU);
}
}
diff --git
a/clang/test/SemaCXX/warn-unsafe-buffer-usage-no-libc-functions-in-c.c
b/clang/test/SemaCXX/warn-unsafe-buffer-usage-no-libc-functions-in-c.c
new file mode 100644
index 00000000000000..e305c3e140dff9
--- /dev/null
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-no-libc-functions-in-c.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -Wunsafe-buffer-usage %s -verify %s
+
+void* memcpy(void *dst,const void *src, unsigned long size);
+
+void f(int *p, int *q) {
+
+ memcpy(p, q, 10); // no libc warn in C
+ ++p[5]; // expected-warning{{unsafe buffer access}}
+}
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