From 92bd8c70a6837b647a6c55964f8d0a50bf561dbc Mon Sep 17 00:00:00 2001
From: John Thompson <John.Thompson.JTSoftware@gmail.com>
Date: Mon, 2 Nov 2009 22:28:12 +0000
Subject: [PATCH] Added __has_include and __has_include_next.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@85834 91177308-0d34-0410-b5e6-96231b3b80d8
---
docs/LanguageExtensions.html | 64 +++++++++++
include/clang/Basic/DiagnosticLexKinds.td | 1 +
include/clang/Lex/Preprocessor.h | 2 +
lib/Headers/stdint.h | 3 +-
lib/Lex/PPMacroExpansion.cpp | 131 +++++++++++++++++++++-
test/Preprocessor/has_include.c | 83 ++++++++++++++
6 files changed, 281 insertions(+), 3 deletions(-)
create mode 100644 test/Preprocessor/has_include.c
diff --git a/docs/LanguageExtensions.html b/docs/LanguageExtensions.html
index 9ac35e1dc2d..1c892fd23a5 100644
--- a/docs/LanguageExtensions.html
+++ b/docs/LanguageExtensions.html
@@ -20,6 +20,7 @@ td {
<ul>
<li><a href="#intro">Introduction</a></li>
<li><a href="#feature_check">Feature Checking Macros</a></li>
+<li><a href="#has_include">Include File Checking Macros</a></li>
<li><a href="#builtinmacros">Builtin Macros</a></li>
<li><a href="#vectors">Vectors and Extended Vectors</a></li>
<li><a href="#blocks">Blocks</a></li>
@@ -112,6 +113,69 @@ can be used like this:</p>
<p>The feature tag is described along with the language feature below.</p>
+<!-- ======================================================================= -->
+<h2 id="has_include">Include File Checking Macros</h2>
+<!-- ======================================================================= -->
+
+<p>Not all developments systems have the same include files.
+The <a href="#__has_include">__has_include</a> and
+<a href="#__has_include_next">__has_include_next</a> macros allow you to
+check for the existence of an include file before doing
+a possibly failing #include directive.</p>
+
+<!-- ======================================================================= -->
+<h3 id="__has_include">__has_include</h3>
+<!-- ======================================================================= -->
+
+<p>This function-like macro takes a single file name string argument that
+is the name of an include file. It evaluates to 1 if the file can
+be found using the include paths, or 0 otherwise:</p>
+
+<blockquote>
+<pre>
+// Note the two possible file name string formats.
+#if __has_include("myinclude.h") && __has_include(<stdint.h>)
+# include "myinclude.h"
+#endif
+
+// To avoid problem with non-clang compilers not having this macro.
+#if defined(__has_include) && __has_include("myinclude.h")
+# include "myinclude.h"
+#endif
+</pre>
+</blockquote>
+
+<p>To test for this feature, use #if defined(__has_include).</p>
+
+<!-- ======================================================================= -->
+<h3 id="__has_include_next">__has_include_next</h3>
+<!-- ======================================================================= -->
+
+<p>This function-like macro takes a single file name string argument that
+is the name of an include file. It is like __has_include except that it
+looks for the second instance of the given file found in the include
+paths. It evaluates to 1 if the second instance of the file can
+be found using the include paths, or 0 otherwise:</p>
+
+<blockquote>
+<pre>
+// Note the two possible file name string formats.
+#if __has_include_next("myinclude.h") && __has_include_next(<stdint.h>)
+# include_next "myinclude.h"
+#endif
+
+// To avoid problem with non-clang compilers not having this macro.
+#if defined(__has_include_next) && __has_include_next("myinclude.h")
+# include_next "myinclude.h"
+#endif
+</pre>
+</blockquote>
+
+<p>Note that __has_include_next, like the GNU extension
+#include_next directive, is intended for use in headers only,
+and will issue a warning if used in the top-level compilation
+file. A warning will also be issued if an absolute path
+is used in the file argument.</p>
<!-- ======================================================================= -->
<h2 id="builtinmacros">Builtin Macros</h2>
diff --git a/include/clang/Basic/DiagnosticLexKinds.td b/include/clang/Basic/DiagnosticLexKinds.td
index f8c013427ca..bbc551373d9 100644
--- a/include/clang/Basic/DiagnosticLexKinds.td
+++ b/include/clang/Basic/DiagnosticLexKinds.td
@@ -194,6 +194,7 @@ def err_pp_expected_eol : Error<
"expected end of line in preprocessor expression">;
def err_pp_defined_requires_identifier : Error<
"operator 'defined' requires an identifier">;
+def err_pp_missing_lparen : Error<"missing '(' after '%0'">;
def err_pp_missing_rparen : Error<"missing ')' after '%0'">;
def err_pp_colon_without_question : Error<"':' without preceding '?'">;
def err_pp_division_by_zero : Error<
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index d721278cbe7..35960ff328a 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -75,6 +75,8 @@ class Preprocessor {
IdentifierInfo *Ident_Pragma, *Ident__VA_ARGS__; // _Pragma, __VA_ARGS__
IdentifierInfo *Ident__has_feature; // __has_feature
IdentifierInfo *Ident__has_builtin; // __has_builtin
+ IdentifierInfo *Ident__has_include; // __has_include
+ IdentifierInfo *Ident__has_include_next; // __has_include_next
SourceLocation DATELoc, TIMELoc;
unsigned CounterValue; // Next __COUNTER__ value.
diff --git a/lib/Headers/stdint.h b/lib/Headers/stdint.h
index a7020d838ec..f79a0f4af55 100644
--- a/lib/Headers/stdint.h
+++ b/lib/Headers/stdint.h
@@ -28,7 +28,8 @@
/* If we're hosted, fall back to the system's stdint.h, which might have
* additional definitions.
*/
-#if __STDC_HOSTED__
+#if __STDC_HOSTED__ && \
+ defined(__has_include_next) && __has_include_next(<stdint.h>)
# include_next <stdint.h>
#else
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 7ddf215020d..699b701ea87 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -64,8 +64,10 @@ void Preprocessor::RegisterBuiltinMacros() {
Ident__TIMESTAMP__ = RegisterBuiltinMacro(*this, "__TIMESTAMP__");
// Clang Extensions.
- Ident__has_feature = RegisterBuiltinMacro(*this, "__has_feature");
- Ident__has_builtin = RegisterBuiltinMacro(*this, "__has_builtin");
+ Ident__has_feature = RegisterBuiltinMacro(*this, "__has_feature");
+ Ident__has_builtin = RegisterBuiltinMacro(*this, "__has_builtin");
+ Ident__has_include = RegisterBuiltinMacro(*this, "__has_include");
+ Ident__has_include_next = RegisterBuiltinMacro(*this, "__has_include_next");
}
/// isTrivialSingleTokenExpansion - Return true if MI, which has a single token
@@ -503,6 +505,117 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
}
}
+/// EvaluateHasIncludeCommon - Process a '__has_include("path")'
+/// or '__has_include_next("path")' expression.
+/// Returns true if successful.
+static bool EvaluateHasIncludeCommon(bool &Result, Token &Tok,
+ IdentifierInfo *II, Preprocessor &PP,
+ const DirectoryLookup *LookupFrom) {
+ SourceLocation LParenLoc;
+
+ // Get '('.
+ PP.LexNonComment(Tok);
+
+ // Ensure we have a '('.
+ if (Tok.isNot(tok::l_paren)) {
+ PP.Diag(Tok.getLocation(), diag::err_pp_missing_lparen) << II->getName();
+ return false;
+ }
+
+ // Save '(' location for possible missing ')' message.
+ LParenLoc = Tok.getLocation();
+
+ // Get the file name.
+ PP.getCurrentLexer()->LexIncludeFilename(Tok);
+
+ // Reserve a buffer to get the spelling.
+ llvm::SmallVector<char, 128> FilenameBuffer;
+ const char *FilenameStart, *FilenameEnd;
+
+ switch (Tok.getKind()) {
+ case tok::eom:
+ // If the token kind is EOM, the error has already been diagnosed.
+ return false;
+
+ case tok::angle_string_literal:
+ case tok::string_literal: {
+ FilenameBuffer.resize(Tok.getLength());
+ FilenameStart = &FilenameBuffer[0];
+ unsigned Len = PP.getSpelling(Tok, FilenameStart);
+ FilenameEnd = FilenameStart+Len;
+ break;
+ }
+
+ case tok::less:
+ // This could be a <foo/bar.h> file coming from a macro expansion. In this
+ // case, glue the tokens together into FilenameBuffer and interpret those.
+ FilenameBuffer.push_back('<');
+ if (PP.ConcatenateIncludeName(FilenameBuffer))
+ return false; // Found <eom> but no ">"? Diagnostic already emitted.
+ FilenameStart = FilenameBuffer.data();
+ FilenameEnd = FilenameStart + FilenameBuffer.size();
+ break;
+ default:
+ PP.Diag(Tok.getLocation(), diag::err_pp_expects_filename);
+ return false;
+ }
+
+ bool isAngled = PP.GetIncludeFilenameSpelling(Tok.getLocation(),
+ FilenameStart, FilenameEnd);
+ // If GetIncludeFilenameSpelling set the start ptr to null, there was an
+ // error.
+ if (FilenameStart == 0) {
+ return false;
+ }
+
+ // Search include directories.
+ const DirectoryLookup *CurDir;
+ const FileEntry *File = PP.LookupFile(FilenameStart, FilenameEnd,
+ isAngled, LookupFrom, CurDir);
+
+ // Get the result value. Result = true means the file exists.
+ Result = File != 0;
+
+ // Get ')'.
+ PP.LexNonComment(Tok);
+
+ // Ensure we have a trailing ).
+ if (Tok.isNot(tok::r_paren)) {
+ PP.Diag(Tok.getLocation(), diag::err_pp_missing_rparen) << II->getName();
+ PP.Diag(LParenLoc, diag::note_matching) << "(";
+ return false;
+ }
+
+ return true;
+}
+
+/// EvaluateHasInclude - Process a '__has_include("path")' expression.
+/// Returns true if successful.
+static bool EvaluateHasInclude(bool &Result, Token &Tok, IdentifierInfo *II,
+ Preprocessor &PP) {
+ return(EvaluateHasIncludeCommon(Result, Tok, II, PP, NULL));
+}
+
+/// EvaluateHasIncludeNext - Process '__has_include_next("path")' expression.
+/// Returns true if successful.
+static bool EvaluateHasIncludeNext(bool &Result, Token &Tok,
+ IdentifierInfo *II, Preprocessor &PP) {
+ // __has_include_next is like __has_include, except that we start
+ // searching after the current found directory. If we can't do this,
+ // issue a diagnostic.
+ const DirectoryLookup *Lookup = PP.GetCurDirLookup();
+ if (PP.isInPrimaryFile()) {
+ Lookup = 0;
+ PP.Diag(Tok, diag::pp_include_next_in_primary);
+ } else if (Lookup == 0) {
+ PP.Diag(Tok, diag::pp_include_next_absolute_path);
+ } else {
+ // Start looking up in the next directory.
+ ++Lookup;
+ }
+
+ return(EvaluateHasIncludeCommon(Result, Tok, II, PP, Lookup));
+}
/// ExpandBuiltinMacro - If an identifier token is read that is to be expanded
/// as a builtin macro, handle it and return the next token as 'Tok'.
@@ -671,6 +784,20 @@ void Preprocessor::ExpandBuiltinMacro(Token &Tok) {
sprintf(TmpBuffer, "%d", (int)Value);
Tok.setKind(tok::numeric_constant);
CreateString(TmpBuffer, strlen(TmpBuffer), Tok, Tok.getLocation());
+ } else if (II == Ident__has_include ||
+ II == Ident__has_include_next) {
+ // The argument to these two builtins should be a parenthesized
+ // file name string literal using angle brackets (<>) or
+ // double-quotes ("").
+ bool Value = false;
+ bool IsValid;
+ if (II == Ident__has_include)
+ IsValid = EvaluateHasInclude(Value, Tok, II, *this);
+ else
+ IsValid = EvaluateHasIncludeNext(Value, Tok, II, *this);
+ sprintf(TmpBuffer, "%d", (int)Value);
+ Tok.setKind(tok::numeric_constant);
+ CreateString(TmpBuffer, strlen(TmpBuffer), Tok, Tok.getLocation());
} else {
assert(0 && "Unknown identifier!");
}
diff --git a/test/Preprocessor/has_include.c b/test/Preprocessor/has_include.c
new file mode 100644
index 00000000000..40697c099f4
--- /dev/null
+++ b/test/Preprocessor/has_include.c
@@ -0,0 +1,83 @@
+// RUN: clang-cc -Eonly -verify %s
+
+// Try different path permutations of __has_include with existing file.
+#if __has_include("stdio.h")
+#else
+ #error "__has_include failed (1)."
+#endif
+
+#if __has_include(<stdio.h>)
+#else
+ #error "__has_include failed (2)."
+#endif
+
+// Try unary expression.
+#if !__has_include("stdio.h")
+ #error "__has_include failed (5)."
+#endif
+
+// Try binary expression.
+#if __has_include("stdio.h") && __has_include("stddef.h")
+#else
+ #error "__has_include failed (6)."
+#endif
+
+// Try non-existing file.
+#if __has_include("blahblah.h")
+ #error "__has_include failed (7)."
+#endif
+
+// Try defined.
+#if !defined(__has_include)
+ #error "defined(__has_include) failed (8)."
+#endif
+
+// Try different path permutations of __has_include_next with existing file.
+#if __has_include_next("stddef.h") // expected-warning {{#include_next in primary source file}}
+#else
+ #error "__has_include failed (1)."
+#endif
+
+#if __has_include_next(<stddef.h>) // expected-warning {{#include_next in primary source file}}
+#else
+ #error "__has_include failed (2)."
+#endif
+
+// Try unary expression.
+#if !__has_include_next("stdio.h") // expected-warning {{#include_next in primary source file}}
+ #error "__has_include_next failed (5)."
+#endif
+
+// Try binary expression.
+#if __has_include_next("stdio.h") && __has_include("stddef.h") // expected-warning {{#include_next in primary source file}}
+#else
+ #error "__has_include_next failed (6)."
+#endif
+
+// Try non-existing file.
+#if __has_include_next("blahblah.h") // expected-warning {{#include_next in primary source file}}
+ #error "__has_include_next failed (7)."
+#endif
+
+// Try defined.
+#if !defined(__has_include_next)
+ #error "defined(__has_include_next) failed (8)."
+#endif
+
+// Try badly formed expressions.
+// FIXME: I don't quite know how to avoid preprocessor side effects.
+// Use FileCheck?
+// It also assert due to unterminated #if's.
+//#if __has_include("stdio.h"
+//#if __has_include "stdio.h")
+//#if __has_include(stdio.h)
+//#if __has_include()
+//#if __has_include(
+//#if __has_include)
+//#if __has_include
+//#if __has_include(<stdio.h>
+//#if __has_include<stdio.h>)
+//#if __has_include("stdio.h)
+//#if __has_include(stdio.h")
+//#if __has_include(<stdio.h)
+//#if __has_include(stdio.h>)
--
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