[clang] [clang] Avoid crash due to unimplemented StructuralValue support in the template differ (PR #93265)
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Thu May 23 20:02:37 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang
Author: Matheus Izvekov (mizvekov)
<details>
<summary>Changes</summary>
This was not implemented in https://github.com/llvm/llvm-project/pull/78041 when StructuralValue TemplateArguments were originally added.
This patch does not implement this functionality, it just falls back to the expression when possible.
Otherwise, such as when dealing with canonical types to begin with, this will just ignore the argument as if it wasn't even there.
Fixes https://github.com/llvm/llvm-project/issues/93068
---
Full diff: https://github.com/llvm/llvm-project/pull/93265.diff
4 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+1)
- (modified) clang/lib/AST/ASTDiagnostic.cpp (+64-42)
- (renamed) clang/test/Misc/diag-template-diffing-cxx11.cpp ()
- (added) clang/test/Misc/diag-template-diffing-cxx26.cpp (+49)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 7bcdee96e213e..6e8687fadc6f7 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -790,6 +790,7 @@ Miscellaneous Clang Crashes Fixed
- Do not attempt to dump the layout of dependent types or invalid declarations
when ``-fdump-record-layouts-complete`` is passed. Fixes #GH83684.
+- Unhandled StructuralValues in the template differ (#GH93068).
OpenACC Specific Changes
------------------------
diff --git a/clang/lib/AST/ASTDiagnostic.cpp b/clang/lib/AST/ASTDiagnostic.cpp
index 91bc1b22acfc7..7e4a5709a44ce 100644
--- a/clang/lib/AST/ASTDiagnostic.cpp
+++ b/clang/lib/AST/ASTDiagnostic.cpp
@@ -1215,46 +1215,19 @@ class TemplateDiff {
bool &NeedAddressOf) {
if (!Iter.isEnd()) {
switch (Iter->getKind()) {
- default:
- llvm_unreachable("unknown ArgumentKind");
- case TemplateArgument::Integral:
- Value = Iter->getAsIntegral();
- HasInt = true;
- IntType = Iter->getIntegralType();
- return;
- case TemplateArgument::Declaration: {
- VD = Iter->getAsDecl();
- QualType ArgType = Iter->getParamTypeForDecl();
- QualType VDType = VD->getType();
- if (ArgType->isPointerType() &&
- Context.hasSameType(ArgType->getPointeeType(), VDType))
- NeedAddressOf = true;
- return;
- }
- case TemplateArgument::NullPtr:
- IsNullPtr = true;
- return;
- case TemplateArgument::Expression:
- E = Iter->getAsExpr();
- }
- } else if (!Default->isParameterPack()) {
- E = Default->getDefaultArgument().getArgument().getAsExpr();
- }
-
- if (!Iter.hasDesugaredTA()) return;
-
- const TemplateArgument& TA = Iter.getDesugaredTA();
- switch (TA.getKind()) {
- default:
- llvm_unreachable("unknown ArgumentKind");
+ case TemplateArgument::StructuralValue:
+ // FIXME: Diffing of structural values is not implemented.
+ // There is no possible fallback in this case, this will show up
+ // as '(no argument)'.
+ return;
case TemplateArgument::Integral:
- Value = TA.getAsIntegral();
+ Value = Iter->getAsIntegral();
HasInt = true;
- IntType = TA.getIntegralType();
+ IntType = Iter->getIntegralType();
return;
case TemplateArgument::Declaration: {
- VD = TA.getAsDecl();
- QualType ArgType = TA.getParamTypeForDecl();
+ VD = Iter->getAsDecl();
+ QualType ArgType = Iter->getParamTypeForDecl();
QualType VDType = VD->getType();
if (ArgType->isPointerType() &&
Context.hasSameType(ArgType->getPointeeType(), VDType))
@@ -1265,13 +1238,62 @@ class TemplateDiff {
IsNullPtr = true;
return;
case TemplateArgument::Expression:
- // TODO: Sometimes, the desugared template argument Expr differs from
- // the sugared template argument Expr. It may be useful in the future
- // but for now, it is just discarded.
- if (!E)
- E = TA.getAsExpr();
- return;
+ E = Iter->getAsExpr();
+ break;
+ case TemplateArgument::Null:
+ case TemplateArgument::Type:
+ case TemplateArgument::Template:
+ case TemplateArgument::TemplateExpansion:
+ llvm_unreachable("TemplateArgument kind is not expected for NTTP");
+ case TemplateArgument::Pack:
+ llvm_unreachable("TemplateArgument kind handled elsewhere");
+ }
+ } else if (!Default->isParameterPack()) {
+ E = Default->getDefaultArgument().getArgument().getAsExpr();
}
+
+ if (!Iter.hasDesugaredTA())
+ return;
+
+ const TemplateArgument &TA = Iter.getDesugaredTA();
+ switch (TA.getKind()) {
+ case TemplateArgument::StructuralValue:
+ // FIXME: Diffing of structural values is not implemented.
+ // Just fall back to the expression.
+ return;
+ case TemplateArgument::Integral:
+ Value = TA.getAsIntegral();
+ HasInt = true;
+ IntType = TA.getIntegralType();
+ return;
+ case TemplateArgument::Declaration: {
+ VD = TA.getAsDecl();
+ QualType ArgType = TA.getParamTypeForDecl();
+ QualType VDType = VD->getType();
+ if (ArgType->isPointerType() &&
+ Context.hasSameType(ArgType->getPointeeType(), VDType))
+ NeedAddressOf = true;
+ return;
+ }
+ case TemplateArgument::NullPtr:
+ IsNullPtr = true;
+ return;
+ case TemplateArgument::Expression:
+ // TODO: Sometimes, the desugared template argument Expr differs from
+ // the sugared template argument Expr. It may be useful in the future
+ // but for now, it is just discarded.
+ if (!E)
+ E = TA.getAsExpr();
+ return;
+ case TemplateArgument::Null:
+ case TemplateArgument::Type:
+ case TemplateArgument::Template:
+ case TemplateArgument::TemplateExpansion:
+ llvm_unreachable("TemplateArgument kind is not expected for NTTP");
+ case TemplateArgument::Pack:
+ llvm_unreachable("TemplateArgument kind handled elsewhere");
+ }
+ llvm_unreachable("Unexpected TemplateArgument kind");
}
/// DiffNonTypes - Handles any template parameters not handled by DiffTypes
diff --git a/clang/test/Misc/diag-template-diffing.cpp b/clang/test/Misc/diag-template-diffing-cxx11.cpp
similarity index 100%
rename from clang/test/Misc/diag-template-diffing.cpp
rename to clang/test/Misc/diag-template-diffing-cxx11.cpp
diff --git a/clang/test/Misc/diag-template-diffing-cxx26.cpp b/clang/test/Misc/diag-template-diffing-cxx26.cpp
new file mode 100644
index 0000000000000..cc174d6c334fb
--- /dev/null
+++ b/clang/test/Misc/diag-template-diffing-cxx26.cpp
@@ -0,0 +1,49 @@
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++26 -verify=expected,notree
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++26 -fno-elide-type -verify=expected,notree
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++26 -fdiagnostics-show-template-tree -verify=expected,tree
+// RUN: %clang_cc1 -fsyntax-only %s -std=c++26 -fno-elide-type -fdiagnostics-show-template-tree -verify=expected,tree
+
+namespace GH93068 {
+ int n[2];
+
+ template <auto> struct A {}; // #A
+
+ namespace t1 {
+ // notree-error@#1 {{no viable conversion from 'A<0>' to 'A<n + 1>'}}
+
+ /* tree-error@#1 {{no viable conversion
+ A<
+ [0 != n + 1]>}}*/
+
+ A<n + 1> v1 = A<0>(); // #1
+ // expected-note@#A {{no known conversion from 'A<0>' to 'const A<&n[1]> &' for 1st argument}}
+ // expected-note@#A {{no known conversion from 'A<0>' to 'A<&n[1]> &&' for 1st argument}}
+
+ // notree-error@#2 {{no viable conversion from 'A<n>' to 'A<(no argument)>'}}
+ /* tree-error@#2 {{no viable conversion
+ A<
+ [n != (no argument)]>}}*/
+
+ A<n + 1> v2 = A<n>(); // #2
+ // expected-note@#A {{no known conversion from 'A<n>' to 'const A<&n[1]> &' for 1st argument}}
+ // expected-note@#A {{no known conversion from 'A<n>' to 'A<&n[1]> &&' for 1st argument}}
+ } // namespace t1
+
+ namespace t2 {
+ A<n> v1;
+ A<n + 1> v2;
+
+ // notree-note@#A {{no known conversion from 'A<n>' to 'const A<(no argument)>' for 1st argument}}
+ // notree-note@#A {{no known conversion from 'A<n>' to 'A<(no argument)>' for 1st argument}}
+
+ /* tree-note@#A {{no known conversion from argument type to parameter type for 1st argument
+ [(no qualifiers) != const] A<
+ [n != (no argument)]>}}*/
+
+ /* tree-note@#A {{no known conversion from argument type to parameter type for 1st argument
+ A<
+ [n != (no argument)]>}}*/
+
+ void f() { v2 = v1; } // expected-error {{no viable overloaded '='}}
+ } // namespace t2
+} // namespace GH93068
``````````
</details>
https://github.com/llvm/llvm-project/pull/93265
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