Strengthen -Wint-conversion to default to an error

Clang has traditionally allowed C programs to implicitly convert
integers to pointers and pointers to integers, despite it not being
valid to do so

Strengthen -Wint-conversion to default to an error

Clang has traditionally allowed C programs to implicitly convert
integers to pointers and pointers to integers, despite it not being
valid to do so except under special circumstances (like converting the
integer 0, which is the null pointer constant, to a pointer). In C89,
this would result in undefined behavior per 3.3.4, and in C99 this rule
was strengthened to be a constraint violation instead. Constraint
violations are most often handled as an error.

This patch changes the warning to default to an error in all C modes
(it is already an error in C++). This gives us better security posture
by calling out potential programmer mistakes in code but still allows
users who need this behavior to use -Wno-error=int-conversion to retain
the warning behavior, or -Wno-int-conversion to silence the diagnostic
entirely.

Differential Revision: https://reviews.llvm.org/D129881

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Use functions with prototypes when appropriate; NFC

A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a protot

Use functions with prototypes when appropriate; NFC

A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,

void func();

becomes

void func(void);

This is the fourth batch of tests being updated (there are a significant
number of other tests left to be updated).

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Improve diagnostics when we fail to convert from a source type to a
destination type for initialization, assignment, parameter-passing,
etc. The main issue fixed here is that we used rather confusing

Improve diagnostics when we fail to convert from a source type to a
destination type for initialization, assignment, parameter-passing,
etc. The main issue fixed here is that we used rather confusing
wording for diagnostics such as

t.c:2:9: warning: initializing 'char const [2]' discards qualifiers,
expected 'char *' [-pedantic]
char *name = __func__;
^ ~~~~~~~~

We're not initializing a 'char const [2]', we're initializing a 'char
*' with an expression of type 'char const [2]'. Similar problems
existed for other diagnostics in this area, so I've normalized them all
with more precise descriptive text to say what we're
initializing/converting/assigning/etc. from and to. The warning for
the code above is now:

t.c:2:9: warning: initializing 'char *' from an expression of type
'char const [2]' discards qualifiers [-pedantic]
char *name = __func__;
^ ~~~~~~~~

Fixes <rdar://problem/7447179>.

llvm-svn: 100832

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Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead o

Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).

llvm-svn: 91446

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Prep for new warning.

llvm-svn: 76709

Rename clang to clang-cc.

Tests and drivers updated, still need to shuffle dirs.

llvm-svn: 67602

Fix PR2042. One remaining issue: we don't currently diagnose

int foobar(int);
int foobar() {}

which requires ifdef'ing out a testcase in predefined-function.c.

llvm-svn: 47236

add comments for the various AssignConvertType's, and split int->pointer from pointer->int.

llvm-svn: 45591

Merge all the 'assignment' diagnostic code into one routine, decloning
it from several places. This merges the diagnostics, making them more
uniform and fewer in number. This also simplifies and cl

Merge all the 'assignment' diagnostic code into one routine, decloning
it from several places. This merges the diagnostics, making them more
uniform and fewer in number. This also simplifies and cleans up the code.

Some highlights:
1. This removes a bunch of very-similar diagnostics.
2. This renames AssignmentCheckResult -> AssignConvertType
3. This merges PointerFromInt + IntFromPointer which were always treated the same.
4. This updates a bunch of test cases that have minor changes to the produced diagnostics.

llvm-svn: 45589

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rename -parse-ast-print to -ast-print
rename -parse-ast-dump to -ast-dump
remove -parse-ast, which is redundant with -fsyntax-only

llvm-svn: 42852

Removed option "-parse-ast-check" from clang driver. This is now implemented
using "-parse-ast -verify".

Updated all test cases (using a sed script) that invoked -parse-ast-check to
now use -parse-

Removed option "-parse-ast-check" from clang driver. This is now implemented
using "-parse-ast -verify".

Updated all test cases (using a sed script) that invoked -parse-ast-check to
now use -parse-ast -verify.

Fixed a bug where using "-verify" instead of "-parse-ast-check" would not
correctly create the DiagClient needed to accumulate diagnostics.

llvm-svn: 42365

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Change Expr::isLvalue() to properly deal with ImplicitCastExpr's.

This fixes the following bug...

t.c:1:31: error: expression is not assignable
short x; void foo(char c) { x += c; }

This case, amo

Change Expr::isLvalue() to properly deal with ImplicitCastExpr's.

This fixes the following bug...

t.c:1:31: error: expression is not assignable
short x; void foo(char c) { x += c; }

This case, among others are now captured in implicit-casts.c.

llvm-svn: 41402

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