https://github.com/temyurchenko updated
https://github.com/llvm/llvm-project/pull/93131
>From a8f15038fa0fbe3ba55d136eb459f511d73b0b34 Mon Sep 17 00:00:00 2001
From: Artem Yurchenko <artemyurche...@zoho.com>
Date: Wed, 22 May 2024 23:41:35 -0400
Subject: [PATCH] [clang][AST] fix ast-print of `extern <lang>` with >=2
declarators
Problem: the printer used to ignore all but the first declarator for
unbraced language linkage declarators. Furthemore, that one would
be printed without the final semicolon.
Solution: for unbraced case we traverse all declarators via
`VisitDeclContext`. Furthermore, in appropriate visitors we query
for whether they are a part of the unbraced extern language linkage
spec, and if so, print appropriately.
---
clang/lib/AST/DeclPrinter.cpp | 49 ++++++++++++++-----
clang/test/AST/ast-print-language-linkage.cpp | 31 ++++++++++++
2 files changed, 69 insertions(+), 11 deletions(-)
create mode 100644 clang/test/AST/ast-print-language-linkage.cpp
diff --git a/clang/lib/AST/DeclPrinter.cpp b/clang/lib/AST/DeclPrinter.cpp
index 0cf4e64f83b8d..9e7ce96d1b41e 100644
--- a/clang/lib/AST/DeclPrinter.cpp
+++ b/clang/lib/AST/DeclPrinter.cpp
@@ -633,7 +633,7 @@ static void printExplicitSpecifier(ExplicitSpecifier ES,
llvm::raw_ostream &Out,
Out << Proto;
}
-static void MaybePrintTagKeywordIfSupressingScopes(PrintingPolicy &Policy,
+static void maybePrintTagKeywordIfSupressingScopes(PrintingPolicy &Policy,
QualType T,
llvm::raw_ostream &Out) {
StringRef prefix = T->isClassType() ? "class "
@@ -643,6 +643,22 @@ static void
MaybePrintTagKeywordIfSupressingScopes(PrintingPolicy &Policy,
Out << prefix;
}
+/// Return the language of the linkage spec of `D`, if applicable.
+///
+/// \Return - "C" if `D` has been declared with unbraced `extern "C"`
+/// - "C++" if `D` has been declared with unbraced `extern "C++"`
+/// - nullptr in any other case
+static const char *tryGetUnbracedLinkageLanguage(const Decl *D) {
+ const auto *SD = dyn_cast<LinkageSpecDecl>(D->getDeclContext());
+ if (!SD || SD->hasBraces())
+ return nullptr;
+ if (SD->getLanguage() == LinkageSpecLanguageIDs::C)
+ return "C";
+ assert(SD->getLanguage() == LinkageSpecLanguageIDs::CXX &&
+ "unknown language in linkage specification");
+ return "C++";
+}
+
void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
if (!D->getDescribedFunctionTemplate() &&
!D->isFunctionTemplateSpecialization()) {
@@ -662,6 +678,11 @@ void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
CXXConversionDecl *ConversionDecl = dyn_cast<CXXConversionDecl>(D);
CXXDeductionGuideDecl *GuideDecl = dyn_cast<CXXDeductionGuideDecl>(D);
if (!Policy.SuppressSpecifiers) {
+ if (const char *lang = tryGetUnbracedLinkageLanguage(D)) {
+ // the "extern" specifier is implicit
+ assert(D->getStorageClass() == SC_None);
+ Out << "extern \"" << lang << "\" ";
+ }
switch (D->getStorageClass()) {
case SC_None: break;
case SC_Extern: Out << "extern "; break;
@@ -807,7 +828,7 @@ void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
}
if (!Policy.SuppressTagKeyword && Policy.SuppressScope &&
!Policy.SuppressUnwrittenScope)
- MaybePrintTagKeywordIfSupressingScopes(Policy, AFT->getReturnType(),
+ maybePrintTagKeywordIfSupressingScopes(Policy, AFT->getReturnType(),
Out);
AFT->getReturnType().print(Out, Policy, Proto);
Proto.clear();
@@ -932,6 +953,11 @@ void DeclPrinter::VisitVarDecl(VarDecl *D) {
: D->getASTContext().getUnqualifiedObjCPointerType(D->getType());
if (!Policy.SuppressSpecifiers) {
+ if (const char *lang = tryGetUnbracedLinkageLanguage(D)) {
+ // the "extern" specifier is implicit
+ assert(D->getStorageClass() == SC_None);
+ Out << "extern \"" << lang << "\" ";
+ }
StorageClass SC = D->getStorageClass();
if (SC != SC_None)
Out << VarDecl::getStorageClassSpecifierString(SC) << " ";
@@ -961,7 +987,7 @@ void DeclPrinter::VisitVarDecl(VarDecl *D) {
if (!Policy.SuppressTagKeyword && Policy.SuppressScope &&
!Policy.SuppressUnwrittenScope)
- MaybePrintTagKeywordIfSupressingScopes(Policy, T, Out);
+ maybePrintTagKeywordIfSupressingScopes(Policy, T, Out);
printDeclType(T, (isa<ParmVarDecl>(D) && Policy.CleanUglifiedParameters &&
D->getIdentifier())
@@ -1064,6 +1090,8 @@ void
DeclPrinter::VisitNamespaceAliasDecl(NamespaceAliasDecl *D) {
void DeclPrinter::VisitEmptyDecl(EmptyDecl *D) {
prettyPrintAttributes(D);
+ if (const char *lang = tryGetUnbracedLinkageLanguage(D))
+ Out << "extern \"" << lang << "\";";
}
void DeclPrinter::VisitCXXRecordDecl(CXXRecordDecl *D) {
@@ -1136,6 +1164,10 @@ void DeclPrinter::VisitCXXRecordDecl(CXXRecordDecl *D) {
}
void DeclPrinter::VisitLinkageSpecDecl(LinkageSpecDecl *D) {
+ if (!D->hasBraces()) {
+ VisitDeclContext(D);
+ return;
+ }
const char *l;
if (D->getLanguage() == LinkageSpecLanguageIDs::C)
l = "C";
@@ -1144,14 +1176,9 @@ void DeclPrinter::VisitLinkageSpecDecl(LinkageSpecDecl
*D) {
"unknown language in linkage specification");
l = "C++";
}
-
- Out << "extern \"" << l << "\" ";
- if (D->hasBraces()) {
- Out << "{\n";
- VisitDeclContext(D);
- Indent() << "}";
- } else
- Visit(*D->decls_begin());
+ Out << "extern \"" << l << "\" {\n";
+ VisitDeclContext(D);
+ Indent() << "}";
}
void DeclPrinter::printTemplateParameters(const TemplateParameterList *Params,
diff --git a/clang/test/AST/ast-print-language-linkage.cpp
b/clang/test/AST/ast-print-language-linkage.cpp
new file mode 100644
index 0000000000000..7e4dc3f25f062
--- /dev/null
+++ b/clang/test/AST/ast-print-language-linkage.cpp
@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -ast-print %s -o - | FileCheck %s
+
+// CHECK: extern "C" int printf(const char *, ...);
+extern "C" int printf(const char *...);
+
+// CHECK: extern "C++" int f(int);
+// CHECK-NEXT: extern "C++" int g(int);
+extern "C++" int f(int), g(int);
+
+// CHECK: extern "C" char a;
+// CHECK-NEXT: extern "C" char b;
+extern "C" char a, b;
+
+// CHECK: extern "C" {
+// CHECK-NEXT: void foo();
+// CHECK-NEXT: int x;
+// CHECK-NEXT: int y;
+// CHECK-NEXT: extern short z;
+// CHECK-NEXT: }
+extern "C" {
+ void foo(void);
+ int x, y;
+ extern short z;
+}
+
+// CHECK: extern "C" {
+// CHECK-NEXT: }
+extern "C" {}
+
+// CHECK: extern "C++";
+extern "C++";
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