[PATCH] D76504: [clang] Fix crash during template sema checking

[Guillaume Chatelet via Phabricator via cfe-commits]

gchatelet updated this revision to Diff 251780.
gchatelet added a comment.

Address comments


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D76504/new/

https://reviews.llvm.org/D76504

Files:
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/builtins-memcpy-inline.c
  clang/test/Sema/builtins-memcpy-inline.cpp


Index: clang/test/Sema/builtins-memcpy-inline.cpp
===================================================================
--- clang/test/Sema/builtins-memcpy-inline.cpp
+++ clang/test/Sema/builtins-memcpy-inline.cpp
@@ -30,3 +30,9 @@
 void test_memcpy_inline_non_constant_size(void *dst, const void *src, unsigned size) {
   __builtin_memcpy_inline(dst, src, size); // expected-error {{argument to '__builtin_memcpy_inline' must be a constant integer}}
 }
+
+template <unsigned size>
+void test_memcpy_inline_template(void *dst, const void *src) {
+  // we do not try to evaluate size in non intantiated templates.
+  __builtin_memcpy_inline(dst, src, size);
+}
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -1649,11 +1649,16 @@
   case Builtin::BI__builtin_nontemporal_store:
     return SemaBuiltinNontemporalOverloaded(TheCallResult);
   case Builtin::BI__builtin_memcpy_inline: {
-    // __builtin_memcpy_inline size argument is a constant by definition.
-    if (TheCall->getArg(2)->EvaluateKnownConstInt(Context).isNullValue())
+    clang::Expr *SizeOp = TheCall->getArg(2);
+    // We warn about copying to or from `nullptr` pointers when `size` is
+    // greater than 0. When `size` is value dependent we cannot evaluate its
+    // value so we bail<< out.
+    if (SizeOp->isValueDependent())
       break;
-    CheckNonNullArgument(*this, TheCall->getArg(0), TheCall->getExprLoc());
-    CheckNonNullArgument(*this, TheCall->getArg(1), TheCall->getExprLoc());
+    if (!SizeOp->EvaluateKnownConstInt(Context).isNullValue()) {
+      CheckNonNullArgument(*this, TheCall->getArg(0), TheCall->getExprLoc());
+      CheckNonNullArgument(*this, TheCall->getArg(1), TheCall->getExprLoc());
+    }
     break;
   }
 #define BUILTIN(ID, TYPE, ATTRS)


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D76504.251780.patch
Type: text/x-patch
Size: 1885 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20200320/e8ba4c22/attachment.bin>