r373950 - Fix for expanding __pragmas in macro arguments
Amy Huang via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 7 12:41:53 PDT 2019
Author: akhuang
Date: Mon Oct 7 12:41:53 2019
New Revision: 373950
URL: http://llvm.org/viewvc/llvm-project?rev=373950&view=rev
Log:
Fix for expanding __pragmas in macro arguments
Summary:
Avoid parsing __pragma into an annotation token when macro arguments are pre-expanded.
This is what clang currently does when parsing _Pragmas.
Fixes https://bugs.llvm.org/show_bug.cgi?id=41128, where clang crashed
when trying to get the length of an annotation token.
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68114
Modified:
cfe/trunk/lib/Lex/Pragma.cpp
cfe/trunk/test/Preprocessor/pragma_microsoft.c
Modified: cfe/trunk/lib/Lex/Pragma.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/Pragma.cpp?rev=373950&r1=373949&r2=373950&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/Pragma.cpp (original)
+++ cfe/trunk/lib/Lex/Pragma.cpp Mon Oct 7 12:41:53 2019
@@ -121,6 +121,40 @@ void PragmaNamespace::HandlePragma(Prepr
// Preprocessor Pragma Directive Handling.
//===----------------------------------------------------------------------===//
+namespace {
+// TokenCollector provides the option to collect tokens that were "read"
+// and return them to the stream to be read later.
+// Currently used when reading _Pragma/__pragma directives.
+struct TokenCollector {
+ Preprocessor &Self;
+ bool Collect;
+ SmallVector<Token, 3> Tokens;
+ Token &Tok;
+
+ void lex() {
+ if (Collect)
+ Tokens.push_back(Tok);
+ Self.Lex(Tok);
+ }
+
+ void revert() {
+ assert(Collect && "did not collect tokens");
+ assert(!Tokens.empty() && "collected unexpected number of tokens");
+
+ // Push the ( "string" ) tokens into the token stream.
+ auto Toks = std::make_unique<Token[]>(Tokens.size());
+ std::copy(Tokens.begin() + 1, Tokens.end(), Toks.get());
+ Toks[Tokens.size() - 1] = Tok;
+ Self.EnterTokenStream(std::move(Toks), Tokens.size(),
+ /*DisableMacroExpansion*/ true,
+ /*IsReinject*/ true);
+
+ // ... and return the pragma token unchanged.
+ Tok = *Tokens.begin();
+ }
+};
+} // namespace
+
/// HandlePragmaDirective - The "\#pragma" directive has been parsed. Lex the
/// rest of the pragma, passing it to the registered pragma handlers.
void Preprocessor::HandlePragmaDirective(PragmaIntroducer Introducer) {
@@ -166,35 +200,6 @@ void Preprocessor::Handle_Pragma(Token &
// In Case #2, we check the syntax now, but then put the tokens back into the
// token stream for later consumption.
- struct TokenCollector {
- Preprocessor &Self;
- bool Collect;
- SmallVector<Token, 3> Tokens;
- Token &Tok;
-
- void lex() {
- if (Collect)
- Tokens.push_back(Tok);
- Self.Lex(Tok);
- }
-
- void revert() {
- assert(Collect && "did not collect tokens");
- assert(!Tokens.empty() && "collected unexpected number of tokens");
-
- // Push the ( "string" ) tokens into the token stream.
- auto Toks = std::make_unique<Token[]>(Tokens.size());
- std::copy(Tokens.begin() + 1, Tokens.end(), Toks.get());
- Toks[Tokens.size() - 1] = Tok;
- Self.EnterTokenStream(std::move(Toks), Tokens.size(),
- /*DisableMacroExpansion*/ true,
- /*IsReinject*/ true);
-
- // ... and return the _Pragma token unchanged.
- Tok = *Tokens.begin();
- }
- };
-
TokenCollector Toks = {*this, InMacroArgPreExpansion, {}, Tok};
// Remember the pragma token location.
@@ -328,11 +333,15 @@ void Preprocessor::Handle_Pragma(Token &
/// HandleMicrosoft__pragma - Like Handle_Pragma except the pragma text
/// is not enclosed within a string literal.
void Preprocessor::HandleMicrosoft__pragma(Token &Tok) {
+ // During macro pre-expansion, check the syntax now but put the tokens back
+ // into the token stream for later consumption. Same as Handle_Pragma.
+ TokenCollector Toks = {*this, InMacroArgPreExpansion, {}, Tok};
+
// Remember the pragma token location.
SourceLocation PragmaLoc = Tok.getLocation();
// Read the '('.
- Lex(Tok);
+ Toks.lex();
if (Tok.isNot(tok::l_paren)) {
Diag(PragmaLoc, diag::err__Pragma_malformed);
return;
@@ -341,14 +350,14 @@ void Preprocessor::HandleMicrosoft__prag
// Get the tokens enclosed within the __pragma(), as well as the final ')'.
SmallVector<Token, 32> PragmaToks;
int NumParens = 0;
- Lex(Tok);
+ Toks.lex();
while (Tok.isNot(tok::eof)) {
PragmaToks.push_back(Tok);
if (Tok.is(tok::l_paren))
NumParens++;
else if (Tok.is(tok::r_paren) && NumParens-- == 0)
break;
- Lex(Tok);
+ Toks.lex();
}
if (Tok.is(tok::eof)) {
@@ -356,6 +365,12 @@ void Preprocessor::HandleMicrosoft__prag
return;
}
+ // If we're expanding a macro argument, put the tokens back.
+ if (InMacroArgPreExpansion) {
+ Toks.revert();
+ return;
+ }
+
PragmaToks.front().setFlag(Token::LeadingSpace);
// Replace the ')' with an EOD to mark the end of the pragma.
Modified: cfe/trunk/test/Preprocessor/pragma_microsoft.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Preprocessor/pragma_microsoft.c?rev=373950&r1=373949&r2=373950&view=diff
==============================================================================
--- cfe/trunk/test/Preprocessor/pragma_microsoft.c (original)
+++ cfe/trunk/test/Preprocessor/pragma_microsoft.c Mon Oct 7 12:41:53 2019
@@ -51,6 +51,8 @@ __pragma(comment(linker," bar=" BAR))
__pragma(warning(pop)); \
}
+#define PRAGMA_IN_ARGS(p) p
+
void f()
{
__pragma() // expected-warning{{unknown pragma ignored}}
@@ -64,8 +66,16 @@ void f()
// CHECK: #pragma warning(disable: 10000)
// CHECK: ; 1 + (2 > 3) ? 4 : 5;
// CHECK: #pragma warning(pop)
-}
+ // Check that macro arguments can contain __pragma.
+ PRAGMA_IN_ARGS(MACRO_WITH__PRAGMA) // expected-warning {{lower precedence}} \
+ // expected-note 2 {{place parentheses}} \
+ // expected-warning {{expression result unused}}
+// CHECK: #pragma warning(push)
+// CHECK: #pragma warning(disable: 10000)
+// CHECK: ; 1 + (2 > 3) ? 4 : 5;
+// CHECK: #pragma warning(pop)
+}
// This should include macro_arg_directive even though the include
// is looking for test.h This allows us to assign to "n"
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