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llvm-project/clang/test/PCH/pr18806.cpp

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Fix PR18806: Canonicalize the replacement type when deserializing a SubstTemplateTypeParmType What's going on in the test case (without the patch applied) is this: When the header is parsed, decltype(B()) is canonicalized to decltype(Y()), because that was the first parsed equivalent decltype expression. Hence, the TemplateSpecializationType for Id<decltype(B())> ends up with SubstTemplateTypeParmType(T, decltype(Y())) as the AliasedType member. When the PCH file is included and the AST reader reads Id<decltype(B())>, it sees decltype(B()) before decltype(Y()). So, this time decltype(B()) ends up being the canonical type for both decltypes, which leads to an assert violation when the reader calls getSubstTemplateTypeParmType with the non-canonical decltype(Y()) as the replacement type. Reviewers: rsmith Reviewed By: rsmith CC: cfe-commits, aemerson Differential Revision: http://llvm-reviews.chandlerc.com/D3073 llvm-svn: 204005
2014-03-15 18:23:27 +08:00
// RUN: %clang_cc1 -std=c++11 -emit-pch -o %t %s
// RUN: %clang_cc1 -std=c++11 -include-pch %t -verify %s
add option to instantiate templates already in the PCH Add -fpch-instantiate-templates which makes template instantiations be performed already in the PCH instead of it being done in every single file that uses the PCH (but every single file will still do it as well in order to handle its own instantiations). I can see 20-30% build time saved with the few tests I've tried. The change may reorder compiler output and also generated code, but should be generally safe and produce functionally identical code. There are some rare cases that do not compile with it, such as test/PCH/pch-instantiate-templates-forward-decl.cpp. If template instantiation bailed out instead of reporting the error, these instantiations could even be postponed, which would make them work. Enable this by default for clang-cl. MSVC creates PCHs by compiling them using an empty .cpp file, which means templates are instantiated while building the PCH and so the .h needs to be self-contained, making test/PCH/pch-instantiate-templates-forward-decl.cpp to fail with MSVC anyway. So the option being enabled for clang-cl matches this. Differential Revision: https://reviews.llvm.org/D69585
2020-04-19 23:49:47 +08:00
// RUN: %clang_cc1 -std=c++11 -emit-pch -fpch-instantiate-templates -o %t %s
// RUN: %clang_cc1 -std=c++11 -include-pch %t -verify %s
Fix PR18806: Canonicalize the replacement type when deserializing a SubstTemplateTypeParmType What's going on in the test case (without the patch applied) is this: When the header is parsed, decltype(B()) is canonicalized to decltype(Y()), because that was the first parsed equivalent decltype expression. Hence, the TemplateSpecializationType for Id<decltype(B())> ends up with SubstTemplateTypeParmType(T, decltype(Y())) as the AliasedType member. When the PCH file is included and the AST reader reads Id<decltype(B())>, it sees decltype(B()) before decltype(Y()). So, this time decltype(B()) ends up being the canonical type for both decltypes, which leads to an assert violation when the reader calls getSubstTemplateTypeParmType with the non-canonical decltype(Y()) as the replacement type. Reviewers: rsmith Reviewed By: rsmith CC: cfe-commits, aemerson Differential Revision: http://llvm-reviews.chandlerc.com/D3073 llvm-svn: 204005
2014-03-15 18:23:27 +08:00
// expected-no-diagnostics
// Before the patch, this test triggered an assert violation in
// ASTContext::getSubstTemplateTypeParmType.
#ifndef HEADER_INCLUDED
#define HEADER_INCLUDED
template <typename T>
using Id = T;
template <typename X>
struct Class1 {
template <typename Y, typename = decltype(Y())>
struct Nested1;
};
template <typename A>
struct Class2 {
template <typename B, typename = Id<decltype(B())>>
struct Nested2;
};
#else
Class2<char> test;
#endif