C89 had a questionable feature where the compiler would implicitly
declare a function that the user called but was never previously
declared. The resulting function would be globally declared as
extern int func(); -- a function without a prototype which accepts zero
or more arguments.
C99 removed support for this questionable feature due to severe
security concerns. However, there was no deprecation period; C89 had
the feature, C99 didn't. So Clang (and GCC) both supported the
functionality as an extension in C99 and later modes.
C2x no longer supports that function signature as it now requires all
functions to have a prototype, and given the known security issues with
the feature, continuing to support it as an extension is not tenable.
This patch changes the diagnostic behavior for the
-Wimplicit-function-declaration warning group depending on the language
mode in effect. We continue to warn by default in C89 mode (due to the
feature being dangerous to use). However, because this feature will not
be supported in C2x mode, we've diagnosed it as being invalid for so
long, the security concerns with the feature, and the trivial
workaround for users (declare the function), we now default the
extension warning to an error in C99-C17 mode. This still gives users
an easy workaround if they are extensively using the extension in those
modes (they can disable the warning or use -Wno-error to downgrade the
error), but the new diagnostic makes it more clear that this feature is
not supported and should be avoided. In C2x mode, we no longer allow an
implicit function to be defined and treat the situation the same as any
other lookup failure.
Differential Revision: https://reviews.llvm.org/D122983
This adds -no-opaque-pointers to clang tests whose output will
change when opaque pointers are enabled by default. This is
intended to be part of the migration approach described in
https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9.
The patch has been produced by replacing %clang_cc1 with
%clang_cc1 -no-opaque-pointers for tests that fail with opaque
pointers enabled. Worth noting that this doesn't cover all tests,
there's a remaining ~40 tests not using %clang_cc1 that will need
a followup change.
Differential Revision: https://reviews.llvm.org/D123115
compiler is allowed to use optimizations that allow reassociation and
transformations that don’t guaranty accuracy.
For example (x+y)+z is transformed into x+(y+z) . Although
mathematically equivalent, these two expressions may not lead to the
same final result due to errors of summation.
Or x/x is transformed into 1.0 but x could be 0.0, INF or NaN. And so
this transformation also may not lead to the same final result.
Setting the eval method 'ffp-eval-method' or via '#pragma clang fp
eval_method' in this mode, doesn’t have any effect.
This patch adds code to warn the user of this.
Differential Revision: https://reviews.llvm.org/D122155
We have some discission in D99152 and llvm-dev and finially come up with
a solution to add amx specific cast intrinsics. We've support the
intrinsics in llvm IR. This patch is to replace bitcast with amx cast
intrinsics in code emitting in FE.
Differential Revision: https://reviews.llvm.org/D122567
Currently, the regcall calling conversion in Clang doesn't match with
ICC when passing / returning structures. https://godbolt.org/z/axxKMKrW7
This patch tries to fix the problem to match with ICC.
Reviewed By: LuoYuanke
Differential Revision: https://reviews.llvm.org/D122104
Clang is crashing on the following statement
char var[9];
__asm__ ("" : "=r" (var) : "0" (var));
This is similar to existing test: crbug_999160_regtest
The issue happens when EmitAsmStmt is trying to convert input to match
output type length. However, that is not guaranteed to be successful all the
time and if the statement itself is invalid like having an array type in
the example, we should give a regular error message here instead of
using assert().
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D120596
This patch adds -Wno-strict-prototypes to all of the test cases that
use functions without prototypes, but not as the primary concern of the
test. e.g., attributes testing whether they can/cannot be applied to a
function without a prototype, etc.
This is done in preparation for enabling -Wstrict-prototypes by
default.
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 final batch of tests being updated to add prototypes,
hopefully.
MSVC currently doesn't support 80 bits long double. But ICC does support
it on Windows. Besides, there're also some users asked for this feature.
We can find the discussions from stackoverflow, msdn etc.
Given Clang has already support `-mlong-double-80`, extending it to
support for Windows seems worthwhile.
Reviewed By: rnk, erichkeane
Differential Revision: https://reviews.llvm.org/D115441
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 ninth batch of tests being updated (there are a
significant number of other tests left to be updated).
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
The basic idea to this is that a) having a single canonical type makes CSE easier, and b) many of our transforms are inconsistent about which types we end up with based on visit order.
I'm restricting this to constants as for non-constants, we'd have to decide whether the simplicity was worth extra instructions. For constants, there are no extra instructions.
We chose the canonical type as i64 arbitrarily. We might consider changing this to something else in the future if we have cause.
Differential Revision: https://reviews.llvm.org/D115387
D113096 solved the "undefined reference to xxx" issue by adding
constraint *m for the global var. But it has strong side effect due to
the symbol in the assembly being replaced with constraint variable.
This leads to some lowering fails. https://godbolt.org/z/h3nWoerPe
This patch fix the problem by use the constraint *m as place holder
rather than real constraint. It has negligible effect for the existing
code generation.
Reviewed By: skan
Differential Revision: https://reviews.llvm.org/D115225
Operations are emulated by software emulation and “float” instructions.
This patch is allowing the support of _Float16 type without the use of
-max512fp16 flag. The final goal being, perform _Float16 emulation for
all arithmetic expressions.
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
[Clang/Test]: Rename enable_noundef_analysis to disable-noundef-analysis and turn it off by default (2)
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
Resolve lit failures in clang after 8ca4b3e's land
Fix lit test failures in clang-ppc* and clang-x64-windows-msvc
Fix missing failures in clang-ppc64be* and retry fixing clang-x64-windows-msvc
Fix internal_clone(aarch64) inline assembly
Turning on `enable_noundef_analysis` flag allows better codegen by removing freeze instructions.
I modified clang by renaming `enable_noundef_analysis` flag to `disable-noundef-analysis` and turning it off by default.
Test updates are made as a separate patch: D108453
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D105169
Constraint `*m` should be used when the address of a variable is passed
as a value. And the constraint is missing for MS inline assembly when sth
is written to the address of the variable.
The missing would cause FE delete the definition of the static varible,
and then result in "undefined reference to xxx" issue.
Reviewed By: xiangzhangllvm
Differential Revision: https://reviews.llvm.org/D113096
Now that the legacy PM is deprecated for the optimization pipeline, we
can start deleting legacy PM tests.
For tests that test both PMs, merge the RUN lines.
Delete tests specific to the legacy PM.
This patch updates test files after D105169.
Autogenerated test codes are changed by `utils/update_cc_test_checks.py,` and non-autogenerated test codes are changed as follows:
(1) I wrote a python script that (partially) updates the tests using regex: {F18594904} The script is not perfect, but I believe it gives hints about which patterns are updated to have `noundef` attached.
(2) The remaining tests are updated manually.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108453
Aaron Ballman