beanz updated this revision to Diff 365324.
beanz added a comment.
Updating documentation to be more clear about the behavior.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D107095/new/
https://reviews.llvm.org/D107095
Files:
clang/docs/LanguageExtensions.rst
clang/include/clang/Basic/DiagnosticGroups.td
clang/include/clang/Basic/DiagnosticLexKinds.td
clang/include/clang/Basic/IdentifierTable.h
clang/include/clang/Lex/Preprocessor.h
clang/lib/Lex/Pragma.cpp
clang/lib/Lex/Preprocessor.cpp
clang/test/Lexer/Inputs/unsafe-macro-2.h
clang/test/Lexer/Inputs/unsafe-macro.h
clang/test/Lexer/unsafe-macro.c
Index: clang/test/Lexer/unsafe-macro.c
===================================================================
--- /dev/null
+++ clang/test/Lexer/unsafe-macro.c
@@ -0,0 +1,7 @@
+// RUN: %clang_cc1 -Wpedantic-macros %s -fsyntax-only -verify
+#include "Inputs/unsafe-macro.h"
+#include "Inputs/unsafe-macro-2.h"
+
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#if UNSAFE_MACRO
+#endif
Index: clang/test/Lexer/Inputs/unsafe-macro.h
===================================================================
--- /dev/null
+++ clang/test/Lexer/Inputs/unsafe-macro.h
@@ -0,0 +1,27 @@
+// expected-error@+1{{expected (}}
+#pragma clang header_unsafe
+
+// expected-error@+1{{expected identifier}}
+#pragma clang header_unsafe(4
+
+// expected-error@+1{{no macro named foo}}
+#pragma clang header_unsafe(foo)
+
+
+#define UNSAFE_MACRO 1
+// expected-note@+8{{macro marked header_unsafe here}}
+// expected-note@+7{{macro marked header_unsafe here}}
+// expected-note@+6{{macro marked header_unsafe here}}
+// expected-note@+5{{macro marked header_unsafe here}}
+// expected-note@+4{{macro marked header_unsafe here}}
+// expected-note@+3{{macro marked header_unsafe here}}
+// expected-note@+2{{macro marked header_unsafe here}}
+// expected-note@+1{{macro marked header_unsafe here}}
+#pragma clang header_unsafe(UNSAFE_MACRO, "Don't use this!")
+
+#define UNSAFE_MACRO_2 2
+// expected-note@+1{{macro marked header_unsafe here}}
+#pragma clang header_unsafe(UNSAFE_MACRO_2)
+
+// expected-error@+1{{expected )}}
+#pragma clang deprecated(UNSAFE_MACRO
Index: clang/test/Lexer/Inputs/unsafe-macro-2.h
===================================================================
--- /dev/null
+++ clang/test/Lexer/Inputs/unsafe-macro-2.h
@@ -0,0 +1,70 @@
+// expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#if UNSAFE_MACRO
+#endif
+
+// expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#if defined(UNSAFE_MACRO)
+#endif
+
+// expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#ifdef UNSAFE_MACRO
+#endif
+
+// expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#ifndef UNSAFE_MACRO
+#endif
+
+// expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+const int x = UNSAFE_MACRO;
+
+// expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe for use in headers}}
+const int y = UNSAFE_MACRO_2;
+
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe for use in headers}}
+#undef UNSAFE_MACRO_2
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe for use in headers}}
+#define UNSAFE_MACRO_2 2
+
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO_2' has been marked as unsafe for use in headers}}
+const int z = UNSAFE_MACRO_2;
+
+
+// Test that we diagnose on #elif.
+#if 0
+#elif UNSAFE_MACRO
+// expected-warning@-1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#endif
+
+
+// Test that we diagnose on #elifdef.
+#ifdef baz
+#elifdef UNSAFE_MACRO
+// expected-warning@-1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#endif
+
+// Test that we diagnose on #elifndef.
+#ifdef baz
+#elifndef UNSAFE_MACRO
+#endif
+// expected-warning@-2{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+
+// FIXME: These cases are currently not handled because clang doesn't expand
+// conditions on skipped #elif* blocks. See the FIXME notes in
+// Preprocessor::SkipExcludedConditionalBlock.
+
+#define frobble
+
+#ifdef frobble
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#elifndef UNSAFE_MACRO
+#endif
+
+#ifdef frobble
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#elifdef UNSAFE_MACRO
+#endif
+
+#if 1
+// not-expected-warning@+1{{macro 'UNSAFE_MACRO' has been marked as unsafe for use in headers: Don't use this!}}
+#elif UNSAFE_MACRO
+#endif
Index: clang/lib/Lex/Preprocessor.cpp
===================================================================
--- clang/lib/Lex/Preprocessor.cpp
+++ clang/lib/Lex/Preprocessor.cpp
@@ -1413,16 +1413,25 @@
return true;
}
-void Preprocessor::emitMacroExpansionWarnings(const Token &Identifier) {
- if (Identifier.getIdentifierInfo()->isDeprecatedMacro()) {
- auto DepMsg = getMacroDeprecationMsg(Identifier.getIdentifierInfo());
- if (!DepMsg)
- Diag(Identifier, diag::warn_pragma_deprecated_macro_use)
- << Identifier.getIdentifierInfo() << 0;
- else
- Diag(Identifier, diag::warn_pragma_deprecated_macro_use)
- << Identifier.getIdentifierInfo() << 1 << *DepMsg;
- }
+void Preprocessor::emitMacroDeprecationWarning(const Token &Identifier) {
+ auto DepMsg = getMacroDeprecationMsg(Identifier.getIdentifierInfo());
+ if (!DepMsg)
+ Diag(Identifier, diag::warn_pragma_deprecated_macro_use)
+ << Identifier.getIdentifierInfo() << 0;
+ else
+ Diag(Identifier, diag::warn_pragma_deprecated_macro_use)
+ << Identifier.getIdentifierInfo() << 1 << *DepMsg;
+}
+
+void Preprocessor::emitMacroUnsafeHeaderWarning(const Token &Identifier) {
+ auto DepMsg = getHeaderUnsafeMsg(Identifier.getIdentifierInfo());
+ if (DepMsg.first.empty())
+ Diag(Identifier, diag::warn_pragma_header_unsafe_macro_use)
+ << Identifier.getIdentifierInfo() << 0;
+ else
+ Diag(Identifier, diag::warn_pragma_header_unsafe_macro_use)
+ << Identifier.getIdentifierInfo() << 1 << DepMsg.first;
+ Diag(DepMsg.second, diag::note_pp_macro_annotation) << 1;
}
ModuleLoader::~ModuleLoader() = default;
Index: clang/lib/Lex/Pragma.cpp
===================================================================
--- clang/lib/Lex/Pragma.cpp
+++ clang/lib/Lex/Pragma.cpp
@@ -1911,6 +1911,45 @@
}
};
+/// This handles parsing pragmas that take a macro name and optional message
+static IdentifierInfo *HandleMacroAnnotationPragma(Preprocessor &PP, Token &Tok,
+ const char *Pragma,
+ std::string &MessageString) {
+ std::string Macro;
+
+ PP.Lex(Tok);
+ if (Tok.isNot(tok::l_paren)) {
+ PP.Diag(Tok, diag::err_expected) << "(";
+ return nullptr;
+ }
+
+ PP.LexUnexpandedToken(Tok);
+ if (!Tok.is(tok::identifier)) {
+ PP.Diag(Tok, diag::err_expected) << tok::identifier;
+ return nullptr;
+ }
+ IdentifierInfo *II = Tok.getIdentifierInfo();
+
+ if (!II->hasMacroDefinition()) {
+ PP.Diag(Tok, diag::err_pp_visibility_non_macro) << II->getName();
+ return nullptr;
+ }
+
+ PP.Lex(Tok);
+ if (Tok.is(tok::comma)) {
+ PP.Lex(Tok);
+ if (!PP.FinishLexStringLiteral(Tok, MessageString, Pragma,
+ /*AllowMacroExpansion=*/true))
+ return nullptr;
+ }
+
+ if (Tok.isNot(tok::r_paren)) {
+ PP.Diag(Tok, diag::err_expected) << ")";
+ return nullptr;
+ }
+ return II;
+}
+
/// "\#pragma clang deprecated(...)"
///
/// The syntax is
@@ -1922,43 +1961,35 @@
void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
Token &Tok) override {
- std::string Macro, MessageString;
-
- PP.Lex(Tok);
- if (Tok.isNot(tok::l_paren)) {
- PP.Diag(Tok, diag::err_expected) << "(";
- return;
- }
+ std::string MessageString;
- PP.LexUnexpandedToken(Tok);
- if (!Tok.is(tok::identifier)) {
- PP.Diag(Tok, diag::err_expected) << tok::identifier;
- return;
+ if (IdentifierInfo *II = HandleMacroAnnotationPragma(
+ PP, Tok, "#pragma clang deprecated", MessageString)) {
+ II->setIsDeprecatedMacro(true);
+ if (!MessageString.empty())
+ PP.addMacroDeprecationMsg(II, std::move(MessageString));
}
- IdentifierInfo *II = Tok.getIdentifierInfo();
+ }
+};
- if (!II->hasMacroDefinition()) {
- PP.Diag(Tok, diag::err_pp_visibility_non_macro) << II->getName();
- return;
- }
+/// "\#pragma clang header_unsafe(...)"
+///
+/// The syntax is
+/// \code
+/// #pragma clang header_unsafe(MACRO_NAME [, Message])
+/// \endcode
+struct PragmaHeaderUnsafeHandler : public PragmaHandler {
+ PragmaHeaderUnsafeHandler() : PragmaHandler("header_unsafe") {}
- PP.Lex(Tok);
- if (Tok.is(tok::comma)) {
- PP.Lex(Tok);
- if (!PP.FinishLexStringLiteral(Tok, MessageString,
- "#pragma clang deprecated",
- /*AllowMacroExpansion=*/true))
- return;
- }
+ void HandlePragma(Preprocessor &PP, PragmaIntroducer Introducer,
+ Token &Tok) override {
+ std::string MessageString;
- if (Tok.isNot(tok::r_paren)) {
- PP.Diag(Tok, diag::err_expected) << ")";
- return;
+ if (IdentifierInfo *II = HandleMacroAnnotationPragma(
+ PP, Tok, "#pragma clang header_unsafe", MessageString)) {
+ II->setIsHeaderUnsafe(true);
+ PP.addHeaderUnsafeMsg(II, std::move(MessageString), Tok.getLocation());
}
-
- II->setIsDeprecatedMacro(true);
- if (!MessageString.empty())
- PP.addMacroDeprecationMsg(II, std::move(MessageString));
}
};
@@ -1991,6 +2022,7 @@
AddPragmaHandler("clang", new PragmaARCCFCodeAuditedHandler());
AddPragmaHandler("clang", new PragmaAssumeNonNullHandler());
AddPragmaHandler("clang", new PragmaDeprecatedHandler());
+ AddPragmaHandler("clang", new PragmaHeaderUnsafeHandler());
// #pragma clang module ...
auto *ModuleHandler = new PragmaNamespace("module");
Index: clang/include/clang/Lex/Preprocessor.h
===================================================================
--- clang/include/clang/Lex/Preprocessor.h
+++ clang/include/clang/Lex/Preprocessor.h
@@ -15,6 +15,7 @@
#define LLVM_CLANG_LEX_PREPROCESSOR_H
#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticIDs.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/LangOptions.h"
@@ -791,9 +792,18 @@
using WarnUnusedMacroLocsTy = llvm::SmallDenseSet<SourceLocation, 32>;
WarnUnusedMacroLocsTy WarnUnusedMacroLocs;
- /// Deprecation messages for macros provided in #pragma clang deprecated
+ /// This is a pair of an optional message and source location used for pragmas
+ /// that annotate macros like pragma clang header_unsafe and pragma clang
+ /// deprecated. This pair stores the optional message and the location of the
+ /// annotation pragma for use producing diagnostics and notes.
+ using MsgLocationPair = std::pair<std::string, SourceLocation>;
+
+ /// Deprecation messages for macros provided in #pragma clang deprecated.
llvm::DenseMap<const IdentifierInfo *, std::string> MacroDeprecationMsgs;
+ /// Usage warning for macros marked by #pragma clang header_unsafe.
+ llvm::DenseMap<const IdentifierInfo *, MsgLocationPair> HeaderUnsafeMacroMsgs;
+
/// A "freelist" of MacroArg objects that can be
/// reused for quick allocation.
MacroArgs *MacroArgCache = nullptr;
@@ -2406,9 +2416,29 @@
return MsgEntry->second;
}
- void emitMacroExpansionWarnings(const Token &Identifier);
+ void addHeaderUnsafeMsg(const IdentifierInfo *II, std::string Msg,
+ SourceLocation AnnotationLoc) {
+ HeaderUnsafeMacroMsgs.insert(
+ std::make_pair(II, std::make_pair(std::move(Msg), AnnotationLoc)));
+ }
+
+ MsgLocationPair getHeaderUnsafeMsg(const IdentifierInfo *II) {
+ return HeaderUnsafeMacroMsgs.find(II)->second;
+ }
+
+ void emitMacroExpansionWarnings(const Token &Identifier) {
+ if (Identifier.getIdentifierInfo()->isDeprecatedMacro())
+ emitMacroDeprecationWarning(Identifier);
+
+ if (Identifier.getIdentifierInfo()->isHeaderUnsafe() &&
+ !SourceMgr.isInMainFile(Identifier.getLocation()))
+ emitMacroUnsafeHeaderWarning(Identifier);
+ }
private:
+ void emitMacroDeprecationWarning(const Token &Identifier);
+ void emitMacroUnsafeHeaderWarning(const Token &Identifier);
+
Optional<unsigned>
getSkippedRangeForExcludedConditionalBlock(SourceLocation HashLoc);
Index: clang/include/clang/Basic/IdentifierTable.h
===================================================================
--- clang/include/clang/Basic/IdentifierTable.h
+++ clang/include/clang/Basic/IdentifierTable.h
@@ -121,10 +121,13 @@
// True if this is a mangled OpenMP variant name.
unsigned IsMangledOpenMPVariantName : 1;
- // True if this is a deprecated macro
+ // True if this is a deprecated macro.
unsigned IsDeprecatedMacro : 1;
- // 24 bits left in a 64-bit word.
+ // True if this macro is unsafe in headers.
+ unsigned IsHeaderUnsafe : 1;
+
+ // 23 bits left in a 64-bit word.
// Managed by the language front-end.
void *FETokenInfo = nullptr;
@@ -138,7 +141,7 @@
NeedsHandleIdentifier(false), IsFromAST(false), ChangedAfterLoad(false),
FEChangedAfterLoad(false), RevertedTokenID(false), OutOfDate(false),
IsModulesImport(false), IsMangledOpenMPVariantName(false),
- IsDeprecatedMacro(false) {}
+ IsDeprecatedMacro(false), IsHeaderUnsafe(false) {}
public:
IdentifierInfo(const IdentifierInfo &) = delete;
@@ -186,8 +189,11 @@
NeedsHandleIdentifier = true;
HadMacro = true;
} else {
+ // Because calling the setters of these calls recomputes, just set them
+ // manually to avoid recomputing a bunch of times.
+ IsDeprecatedMacro = false;
+ IsHeaderUnsafe = false;
RecomputeNeedsHandleIdentifier();
- setIsDeprecatedMacro(false);
}
}
/// Returns true if this identifier was \#defined to some value at any
@@ -209,6 +215,18 @@
RecomputeNeedsHandleIdentifier();
}
+ bool isHeaderUnsafe() const { return IsHeaderUnsafe; }
+
+ void setIsHeaderUnsafe(bool Val) {
+ if (IsHeaderUnsafe == Val)
+ return;
+ IsHeaderUnsafe = Val;
+ if (Val)
+ NeedsHandleIdentifier = true;
+ else
+ RecomputeNeedsHandleIdentifier();
+ }
+
/// If this is a source-language token (e.g. 'for'), this API
/// can be used to cause the lexer to map identifiers to source-language
/// tokens.
Index: clang/include/clang/Basic/DiagnosticLexKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticLexKinds.td
+++ clang/include/clang/Basic/DiagnosticLexKinds.td
@@ -524,6 +524,16 @@
ExtWarn<"macro %0 has been marked as deprecated%select{|: %2}1">,
InGroup<DeprecatedPragma>;
+// - #pragma clang header_unsafe(...)
+def warn_pragma_header_unsafe_macro_use :
+ ExtWarn<"macro %0 has been marked as unsafe for use in headers"
+ "%select{|: %2}1">,
+ InGroup<PedanticMacros>;
+
+// - Note for macro annotations.
+def note_pp_macro_annotation :
+ Note<"macro marked %select{deprecated|header_unsafe}0 here">;
+
// - #pragma execution_character_set(...)
def warn_pragma_exec_charset_expected :
ExtWarn<"#pragma execution_character_set expected '%0'">,
Index: clang/include/clang/Basic/DiagnosticGroups.td
===================================================================
--- clang/include/clang/Basic/DiagnosticGroups.td
+++ clang/include/clang/Basic/DiagnosticGroups.td
@@ -1305,3 +1305,7 @@
def RTTI : DiagGroup<"rtti">;
def OpenCLCoreFeaturesDiagGroup : DiagGroup<"pedantic-core-features">;
+
+// Warnings and extensions to make preprocessor macro usage pedantic.
+def PedanticMacros : DiagGroup<"pedantic-macros",
+ [DeprecatedPragma, MacroRedefined, BuiltinMacroRedefined]>;
Index: clang/docs/LanguageExtensions.rst
===================================================================
--- clang/docs/LanguageExtensions.rst
+++ clang/docs/LanguageExtensions.rst
@@ -3906,6 +3906,31 @@
``#pragma GCC warning`` because the warning can be controlled with
``-Wdeprecated``.
+Header Unsafe Macros
+====================
+
+Clang supports the pragma ``#pragma clang header_unsafe``, which can be used to
+mark macros as unsafe to use in headers. This can be valuable when providing
+headers with ABI stability requirements. Any expansion of the annotated macro
+processed by the preprocessor after the ``#pragma`` annotation will log a
+a warning. For example:
+
+.. code-block:: c
+
+ #define TARGET_ARM 1
+ #pragma clang header_unsafe(TARGET_ARM, "<reason>")
+
+ /// Foo.h
+ struct Foo {
+ #if TARGET_ARM // warning: TARGET_ARM is marked unsafe in headers: <reason>
+ uint32_t X;
+ #else
+ uint64_t X;
+ #endif
+ };
+
+This warning is controlled by ``-Wpedantic-macros``.
+
Extended Integer Types
======================
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