[clang] 1029747 - [Sema] Fix null pointer dereference handleAlwaysInlineAttr.

[Craig Topper via cfe-commits]

Author: Craig Topper
Date: 2023-03-16T17:49:34-07:00
New Revision: 10297470e953f4f3968c54c851c8af82b07af00b

URL: https://github.com/llvm/llvm-project/commit/10297470e953f4f3968c54c851c8af82b07af00b
DIFF: https://github.com/llvm/llvm-project/commit/10297470e953f4f3968c54c851c8af82b07af00b.diff

LOG: [Sema] Fix null pointer dereference handleAlwaysInlineAttr.

It's possible for `getCalleeDecl()` to return a null pointer.

This was encountered by a user of our downstream compiler.

The case involved a DependentScopeDeclRefExpr.

Since this seems to only be for a warning diagnostic, I skipped
the diagnostic check if it returned null. But mabye there's a
different way to fix this.

Reviewed By: erichkeane

Differential Revision: https://reviews.llvm.org/D146089

Added: 
    

Modified: 
    clang/lib/Sema/SemaStmtAttr.cpp
    clang/test/Sema/attr-alwaysinline.cpp
    clang/test/Sema/attr-noinline.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 6d443837a4c5..eeef85373ccb 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -233,7 +233,8 @@ static Attr *handleNoInlineAttr(Sema &S, Stmt *St, const ParsedAttr &A,
 
   for (const auto *CallExpr : CEF.getCallExprs()) {
     const Decl *Decl = CallExpr->getCalleeDecl();
-    if (Decl->hasAttr<AlwaysInlineAttr>() || Decl->hasAttr<FlattenAttr>())
+    if (Decl &&
+        (Decl->hasAttr<AlwaysInlineAttr>() || Decl->hasAttr<FlattenAttr>()))
       S.Diag(St->getBeginLoc(), diag::warn_function_stmt_attribute_precedence)
           << A << (Decl->hasAttr<AlwaysInlineAttr>() ? 0 : 1);
   }
@@ -259,7 +260,7 @@ static Attr *handleAlwaysInlineAttr(Sema &S, Stmt *St, const ParsedAttr &A,
 
   for (const auto *CallExpr : CEF.getCallExprs()) {
     const Decl *Decl = CallExpr->getCalleeDecl();
-    if (Decl->hasAttr<NoInlineAttr>() || Decl->hasAttr<FlattenAttr>())
+    if (Decl && (Decl->hasAttr<NoInlineAttr>() || Decl->hasAttr<FlattenAttr>()))
       S.Diag(St->getBeginLoc(), diag::warn_function_stmt_attribute_precedence)
           << A << (Decl->hasAttr<NoInlineAttr>() ? 2 : 1);
   }

diff  --git a/clang/test/Sema/attr-alwaysinline.cpp b/clang/test/Sema/attr-alwaysinline.cpp
index 6b8e8f215a4b..213d70407f48 100644
--- a/clang/test/Sema/attr-alwaysinline.cpp
+++ b/clang/test/Sema/attr-alwaysinline.cpp
@@ -25,3 +25,22 @@ void foo() {
 }
 
 [[clang::always_inline]] static int i = bar(); // expected-warning {{'always_inline' attribute only applies to functions and statements}}
+
+// This used to crash the compiler.
+template<int D>
+int foo(int x) {
+    if constexpr (D > 1)
+        [[clang::always_inline]] return foo<D-1>(x + 1);
+    else
+        return x;
+}
+
+// FIXME: This should warn that always_inline statement attribute has higher
+// precedence than the noinline function attribute.
+template<int D> [[gnu::noinline]]
+int bar(int x) {
+    if constexpr (D > 1)
+        [[clang::always_inline]] return bar<D-1>(x + 1);
+    else
+        return x;
+}

diff  --git a/clang/test/Sema/attr-noinline.cpp b/clang/test/Sema/attr-noinline.cpp
index d35782f11adb..a62ca1debcc5 100644
--- a/clang/test/Sema/attr-noinline.cpp
+++ b/clang/test/Sema/attr-noinline.cpp
@@ -25,3 +25,22 @@ void foo() {
 }
 
 [[clang::noinline]] static int i = bar(); // expected-warning {{'noinline' attribute only applies to functions and statements}}
+
+// This used to crash the compiler.
+template<int D>
+int foo(int x) {
+    if constexpr (D > 1)
+        [[clang::noinline]] return foo<D-1>(x + 1);
+    else
+        return x;
+}
+
+// FIXME: This should warn that noinline statement attribute has higher
+// precedence than the always_inline function attribute.
+template<int D> [[clang::always_inline]]
+int bar(int x) {
+    if constexpr (D > 1)
+        [[clang::noinline]] return bar<D-1>(x + 1);
+    else
+        return x;
+}