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Fix bungled parse recovery in K&R function declarations 

void knrNoSemi(i) int i { }

Adherents of The C Programming Language unfortunate enough to miss a semicolon
as above would be met with a cascade of errors spanning the remainder of the
TU.

This patch introduces a beautiful parse error recovery, complete with helpful
FixIt to restore sanity.

Before (output redacted for brevity):

  error: 'error' diagnostics seen but not expected:
    File declarators.c Line 119: declaration does not declare a parameter
    File declarators.c Line 123: declaration does not declare a parameter
    File declarators.c Line 127: parameter named 'func_E12' is missing
    File declarators.c Line 127: expected ';' at end of declaration
    File declarators.c Line 133: parameter named 'func_E13' is missing
    File declarators.c Line 133: expected ';' at end of declaration
    File declarators.c Line 139: parameter named 'func_E14' is missing
    File declarators.c Line 139: expected ';' at end of declaration
    File declarators.c Line 145: parameter named 'func_E15' is missing
    File declarators.c Line 145: expected ';' at end of declaration
    File declarators.c Line 150: expected function body after function declarator
    File declarators.c Line 119: declaration of 'enum E11' will not be visible outside of this function
    File declarators.c Line 123: declaration of 'enum E12' will not be visible outside of this function
    File declarators.c Line 133: ISO C forbids forward references to 'enum' types
    File declarators.c Line 133: declaration of 'enum E13' will not be visible outside of this function
    File declarators.c Line 139: ISO C forbids forward references to 'enum' types
    File declarators.c Line 139: declaration of 'enum E14' will not be visible outside of this function
    File declarators.c Line 145: ISO C forbids forward references to 'enum' types
    File declarators.c Line 145: declaration of 'enum E15' will not be visible outside of this function
    ...

After:

  declarators.c:103:24: error: expected ';' at end of declaration
  void knrNoSemi(i) int i { }
                         ^
                         ;

Patch found in a sealed envelope dated 1978 with the message "Do not open until
January 2014"

llvm-svn: 198540
This commit is contained in:
Alp Toker 2014-01-05 03:27:57 +00:00
parent 094e521e3f
commit eec8101b9b
2 changed files with 4 additions and 6 deletions
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9
clang/lib/Parse/Parser.cpp
View File

@ -1285,12 +1285,9 @@ void Parser::ParseKNRParamDeclarations(Declarator &D) {
ParseDeclarator(ParmDeclarator);
}
if (ExpectAndConsumeSemi(diag::err_expected_semi_declaration)) {
// Skip to end of block or statement
SkipUntil(tok::semi);
if (Tok.is(tok::semi))
ConsumeToken();
}
// Consume ';' or recover by skipping to the mandatory function body.
if (ExpectAndConsumeSemi(diag::err_expected_semi_declaration))
SkipUntil(tok::l_brace, StopBeforeMatch);
}
// The actions module must verify that all arguments were declared.

1
clang/test/Parser/declarators.c
View File

@ -100,6 +100,7 @@ long struct X { int x; } test15(); // expected-error {{'long struct' is invalid}
void test16(i) int i j; { } // expected-error {{expected ';' at end of declaration}}
void test17(i, j) int i, j k; { } // expected-error {{expected ';' at end of declaration}}
void knrNoSemi(i) int i { } // expected-error {{expected ';' at end of declaration}}
// PR12595