Commit Graph

730 Commits

Author SHA1 Message Date
Leonard Chan 8f7caae00a [Fixed Point Arithmetic] Fixed Point and Integer Conversions
This patch includes the necessary code for converting between a fixed point type and integer.
This also includes constant expression evaluation for conversions with these types.

Differential Revision: https://reviews.llvm.org/D56900

llvm-svn: 355462
2019-03-06 00:28:43 +00:00
Erik Pilkington 53e43f4d9e [CodeGen] Fix some broken IR generated by -fsanitize=unsigned-integer-overflow
I think the author of the function assumed that `GetInsertBlock()`
wouldn't change from where `atomicPHI` was created, but this isn't
true when `-fsanitize=unsigned-integer-overflow` is enabled (we
generate an overflow/continuation label). Fix by keeping track of the
block we want to return to to complete the cmpxchg loop.

rdar://48406558

Differential revision: https://reviews.llvm.org/D58744

llvm-svn: 355054
2019-02-28 00:47:55 +00:00
Leonard Chan ce1d4f1bec [Fixed Point Arithmetic] Fixed Point Comparisons
This patch implements fixed point comparisons with other fixed point types and
integers. This also provides constant expression evaluation for them.

Differential Revision: https://reviews.llvm.org/D57219

llvm-svn: 354621
2019-02-21 20:50:09 +00:00
James Y Knight 9871db064d [opaque pointer types] Pass function types for runtime function calls.
Emit{Nounwind,}RuntimeCall{,OrInvoke} have been modified to take a
FunctionCallee as an argument, and CreateRuntimeFunction has been
modified to return a FunctionCallee. All callers have been updated.

Additionally, CreateBuiltinFunction is removed, as it was redundant
with CreateRuntimeFunction after some previous changes.

Differential Revision: https://reviews.llvm.org/D57668

llvm-svn: 353184
2019-02-05 16:42:33 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Leonard Chan 837da5d3ec [Fixed Point Arithmetic] Fixed Point Subtraction
This patch covers subtraction between fixed point types and other fixed point
types or integers, using the conversion rules described in 4.1.4 of N1169.

Differential Revision: https://reviews.llvm.org/D55844

llvm-svn: 351371
2019-01-16 19:53:50 +00:00
Leonard Chan 2044ac89aa [Fixed Point Arithmetic] Fixed Point Addition
This patch covers addition between fixed point types and other fixed point
types or integers, using the conversion rules described in 4.1.4 of N1169.

Usual arithmetic rules do not apply to binary operations when one of the
operands is a fixed point type, and the result of the operation must be
calculated with the full precision of the operands, so we should not perform
any casting to a common type.

This patch does not include constant expression evaluation for addition of
fixed point types. That will be addressed in another patch since I think this
one is already big enough.

Differential Revision: https://reviews.llvm.org/D53738

llvm-svn: 351364
2019-01-16 18:13:59 +00:00
Roman Lebedev bd1c087019 [clang][UBSan] Sanitization for alignment assumptions.
Summary:
UB isn't nice. It's cool and powerful, but not nice.
Having a way to detect it is nice though.
[[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says:
```
We propose to add this functionality via a library function instead of a core language attribute.
...
If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour.
```

This differential teaches clang to sanitize all the various variants of this assume-aligned attribute.

Requires D54588 for LLVM IRBuilder changes.
The compiler-rt part is D54590.

This is a second commit, the original one was r351105,
which was mass-reverted in r351159 because 2 compiler-rt tests were failing.

Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall

Reviewed By: rjmccall

Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54589

llvm-svn: 351177
2019-01-15 09:44:25 +00:00
Vlad Tsyrklevich 86e68fda3b Revert alignment assumptions changes
Revert r351104-6, r351109, r351110, r351119, r351134, and r351153. These
changes fail on the sanitizer bots.

llvm-svn: 351159
2019-01-15 03:38:02 +00:00
Roman Lebedev 7892c37455 [clang][UBSan] Sanitization for alignment assumptions.
Summary:
UB isn't nice. It's cool and powerful, but not nice.
Having a way to detect it is nice though.
[[ https://wg21.link/p1007r3 | P1007R3: std::assume_aligned ]] / http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1007r2.pdf says:
```
We propose to add this functionality via a library function instead of a core language attribute.
...
If the pointer passed in is not aligned to at least N bytes, calling assume_aligned results in undefined behaviour.
```

This differential teaches clang to sanitize all the various variants of this assume-aligned attribute.

Requires D54588 for LLVM IRBuilder changes.
The compiler-rt part is D54590.

Reviewers: ABataev, craig.topper, vsk, rsmith, rnk, #sanitizers, erichkeane, filcab, rjmccall

Reviewed By: rjmccall

Subscribers: chandlerc, ldionne, EricWF, mclow.lists, cfe-commits, bkramer

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54589

llvm-svn: 351105
2019-01-14 19:09:27 +00:00
Richard Trieu 6368818fd5 Move CodeGenOptions from Frontend to Basic
Basic uses CodeGenOptions and should not depend on Frontend.

llvm-svn: 348827
2018-12-11 03:18:39 +00:00
Fangrui Song 407659ab0a Revert "Revert r347417 "Re-Reinstate 347294 with a fix for the failures.""
It seems the two failing tests can be simply fixed after r348037

Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now

llvm-svn: 348053
2018-11-30 23:41:18 +00:00
Fangrui Song f5d3335d75 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:

  extern char extern_var;
  struct { int a; } a = {__builtin_constant_p(extern_var)};

llvm-svn: 348039
2018-11-30 21:26:09 +00:00
Hans Wennborg 48ee4ad325 Re-commit r347417 "Re-Reinstate 347294 with a fix for the failures."
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.

llvm-svn: 347756
2018-11-28 14:04:12 +00:00
Hans Wennborg 8c79706e89 Revert r347417 "Re-Reinstate 347294 with a fix for the failures."
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:

  static bool f(int *a, int *b) {
    return !__builtin_constant_p(b - a) || (!(b - a));
  }

  int arr[] = {1,2,3};

  bool g() {
    return f(arr, arr + 3);
  }

  $ clang -O2 -S -emit-llvm a.cc -o -

g() should return true, but after r347417 it became false for some reason.

This also reverts the follow-up commits.

r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!

r347446:
> The result of is.constant() is unsigned.

r347480:
> A __builtin_constant_p() returns 0 with a function type.

r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.

r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.

llvm-svn: 347656
2018-11-27 14:01:40 +00:00
Bill Wendling 6ff1751f7d Re-Reinstate 347294 with a fix for the failures.
Don't try to emit a scalar expression for a non-scalar argument to
__builtin_constant_p().

Third time's a charm!

llvm-svn: 347417
2018-11-21 20:44:18 +00:00
Nico Weber 9f0246d473 Revert r347364 again, the fix was incomplete.
llvm-svn: 347389
2018-11-21 12:47:43 +00:00
Bill Wendling 91549ed15f Reinstate 347294 with a fix for the failures.
EvaluateAsInt() is sometimes called in a constant context. When that's the
case, we need to specify it as so.

llvm-svn: 347364
2018-11-20 23:24:16 +00:00
Roman Lebedev d677c3fc61 [clang][CodeGen] Implicit Conversion Sanitizer: discover the world of CompoundAssign operators
Summary:
As reported by @regehr (thanks!) on twitter (https://twitter.com/johnregehr/status/1057681496255815686),
we (me) has completely forgot about the binary assignment operator.
In AST, it isn't represented as separate `ImplicitCastExpr`'s,
but as a single `CompoundAssignOperator`, that does all the casts internally.
Which means, out of these two, only the first one is diagnosed:
```
auto foo() {
    unsigned char c = 255;
    c = c + 1;
    return c;
}
auto bar() {
    unsigned char c = 255;
    c += 1;
    return c;
}
```
https://godbolt.org/z/JNyVc4

This patch does handle the `CompoundAssignOperator`:
```
int main() {
  unsigned char c = 255;
  c += 1;
  return c;
}
```
```
$ ./bin/clang -g -fsanitize=integer /tmp/test.c && ./a.out
/tmp/test.c:3:5: runtime error: implicit conversion from type 'int' of value 256 (32-bit, signed) to type 'unsigned char' changed the value to 0 (8-bit, unsigned)
    #0 0x2392b8 in main /tmp/test.c:3:5
    #1 0x7fec4a612b16 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x22b16)
    #2 0x214029 in _start (/build/llvm-build-GCC-release/a.out+0x214029)
```

However, the pre/post increment/decrement is still not handled.

Reviewers: rsmith, regehr, vsk, rjmccall, #sanitizers

Reviewed By: rjmccall

Subscribers: mclow.lists, cfe-commits, regehr

Tags: #clang, #sanitizers

Differential Revision: https://reviews.llvm.org/D53949

llvm-svn: 347258
2018-11-19 19:56:43 +00:00
Bill Wendling 8003edc9aa Compound literals, enums, et al require const expr
Summary:
Compound literals,  enums, file-scoped arrays, etc. require their
initializers and size specifiers to be constant. Wrap the initializer
expressions in a ConstantExpr so that we can easily check for this later
on.

Reviewers: rsmith, shafik

Reviewed By: rsmith

Subscribers: cfe-commits, jyknight, nickdesaulniers

Differential Revision: https://reviews.llvm.org/D53921

llvm-svn: 346455
2018-11-09 00:41:36 +00:00
Andrew Savonichev 3fee351867 [OpenCL] Add support of cl_intel_device_side_avc_motion_estimation extension
Summary:
Documentation can be found at https://www.khronos.org/registry/OpenCL/extensions/intel/cl_intel_device_side_avc_motion_estimation.txt

Patch by Kristina Bessonova


Reviewers: Anastasia, yaxunl, shafik

Reviewed By: Anastasia

Subscribers: arphaman, sidorovd, AlexeySotkin, krisb, bader, asavonic, cfe-commits

Differential Revision: https://reviews.llvm.org/D51484

llvm-svn: 346392
2018-11-08 11:25:41 +00:00
Andrew Savonichev 3b12b7e702 Revert r346326 [OpenCL] Add support of cl_intel_device_side_avc_motion_estimation
This patch breaks Index/opencl-types.cl LIT test:

Script:
--
: 'RUN: at line 1';   stage1/bin/c-index-test -test-print-type llvm/tools/clang/test/Index/opencl-types.cl -cl-std=CL2.0 | stage1/bin/FileCheck llvm/tools/clang/test/Index/opencl-types.cl
--
Command Output (stderr):
--
llvm/tools/clang/test/Index/opencl-types.cl:3:26: warning: unsupported OpenCL extension 'cl_khr_fp16' - ignoring [-Wignored-pragmas]
llvm/tools/clang/test/Index/opencl-types.cl:4:26: warning: unsupported OpenCL extension 'cl_khr_fp64' - ignoring [-Wignored-pragmas]
llvm/tools/clang/test/Index/opencl-types.cl:8:9: error: use of type 'double' requires cl_khr_fp64 extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:11:8: error: declaring variable of type 'half' is not allowed
llvm/tools/clang/test/Index/opencl-types.cl:15:3: error: use of type 'double' requires cl_khr_fp64 extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:16:3: error: use of type 'double4' (vector of 4 'double' values) requires cl_khr_fp64 extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:26:26: warning: unsupported OpenCL extension 'cl_khr_gl_msaa_sharing' - ignoring [-Wignored-pragmas]
llvm/tools/clang/test/Index/opencl-types.cl:35:44: error: use of type '__read_only image2d_msaa_t' requires cl_khr_gl_msaa_sharing extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:36:49: error: use of type '__read_only image2d_array_msaa_t' requires cl_khr_gl_msaa_sharing extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:37:49: error: use of type '__read_only image2d_msaa_depth_t' requires cl_khr_gl_msaa_sharing extension to be enabled
llvm/tools/clang/test/Index/opencl-types.cl:38:54: error: use of type '__read_only image2d_array_msaa_depth_t' requires cl_khr_gl_msaa_sharing extension to be enabled

llvm-svn: 346338
2018-11-07 18:34:19 +00:00
Andrew Savonichev 35dfce723c [OpenCL] Add support of cl_intel_device_side_avc_motion_estimation extension
Summary:
Documentation can be found at https://www.khronos.org/registry/OpenCL/extensions/intel/cl_intel_device_side_avc_motion_estimation.txt

Patch by Kristina Bessonova


Reviewers: Anastasia, yaxunl, shafik

Reviewed By: Anastasia

Subscribers: arphaman, sidorovd, AlexeySotkin, krisb, bader, asavonic, cfe-commits

Differential Revision: https://reviews.llvm.org/D51484

llvm-svn: 346326
2018-11-07 15:44:01 +00:00
Richard Smith 3501895863 Revert r345562: "PR23833, DR2140: an lvalue-to-rvalue conversion on a glvalue of type"
This exposes a (known) CodeGen bug: it can't cope with emitting lvalue
expressions that denote non-odr-used but usable-in-constant-expression
variables. See PR39528 for a testcase.

Reverted for now until that issue can be fixed.

llvm-svn: 346065
2018-11-03 02:23:33 +00:00
Volodymyr Sapsai ef1899b01d [CodeGen] Move `emitConstant` from ScalarExprEmitter to CodeGenFunction. NFC.
The goal is to use `emitConstant` in more places. Didn't move
`ComplexExprEmitter::emitConstant` because it returns a different type.

Reviewers: rjmccall, ahatanak

Reviewed By: rjmccall

Subscribers: dexonsmith, erik.pilkington, cfe-commits

Differential Revision: https://reviews.llvm.org/D53725

llvm-svn: 345897
2018-11-01 21:57:05 +00:00
Reid Kleckner 4dc0b1ac60 Fix clang -Wimplicit-fallthrough warnings across llvm, NFC
This patch should not introduce any behavior changes. It consists of
mostly one of two changes:
1. Replacing fall through comments with the LLVM_FALLTHROUGH macro
2. Inserting 'break' before falling through into a case block consisting
   of only 'break'.

We were already using this warning with GCC, but its warning behaves
slightly differently. In this patch, the following differences are
relevant:
1. GCC recognizes comments that say "fall through" as annotations, clang
   doesn't
2. GCC doesn't warn on "case N: foo(); default: break;", clang does
3. GCC doesn't warn when the case contains a switch, but falls through
   the outer case.

I will enable the warning separately in a follow-up patch so that it can
be cleanly reverted if necessary.

Reviewers: alexfh, rsmith, lattner, rtrieu, EricWF, bollu

Differential Revision: https://reviews.llvm.org/D53950

llvm-svn: 345882
2018-11-01 19:54:45 +00:00
Roman Lebedev 1bb9aea56b [clang][CodeGen] ImplicitIntegerSignChangeSanitizer: actually ignore NOP casts.
I fully expected for that to be handled by the canonical type check,
but it clearly wasn't. Sadly, somehow it hide until now.

Reported by Eli Friedman.

llvm-svn: 345816
2018-11-01 08:56:51 +00:00
Richard Trieu 161121fc9d Silence unused variable warnings. NFC
llvm-svn: 345669
2018-10-30 23:01:15 +00:00
Roman Lebedev 62debd8055 [clang][ubsan] Implicit Conversion Sanitizer - integer sign change - clang part
This is the second half of Implicit Integer Conversion Sanitizer.
It completes the first half, and finally makes the sanitizer
fully functional! Only the bitfield handling is missing.

Summary:
C and C++ are interesting languages. They are statically typed, but weakly.
The implicit conversions are allowed. This is nice, allows to write code
while balancing between getting drowned in everything being convertible,
and nothing being convertible. As usual, this comes with a price:

```
void consume(unsigned int val);

void test(int val) {
  consume(val);
  // The 'val' is `signed int`, but `consume()` takes `unsigned int`.
  // If val is negative, then consume() will be operating on a large
  // unsigned value, and you may or may not have a bug.

  // But yes, sometimes this is intentional.
  // Making the conversion explicit silences the sanitizer.
  consume((unsigned int)val);
}
```

Yes, there is a `-Wsign-conversion`` diagnostic group, but first, it is kinda
noisy, since it warns on everything (unlike sanitizers, warning on an
actual issues), and second, likely there are cases where it does **not** warn.

The actual detection is pretty easy. We just need to check each of the values
whether it is negative, and equality-compare the results of those comparisons.
The unsigned value is obviously non-negative. Zero is non-negative too.
https://godbolt.org/g/w93oj2

We do not have to emit the check *always*, there are obvious situations
where we can avoid emitting it, since it would **always** get optimized-out.
But i do think the tautological IR (`icmp ult %x, 0`, which is always false)
should be emitted, and the middle-end should cleanup it.

This sanitizer is in the `-fsanitize=implicit-conversion` group,
and is a logical continuation of D48958 `-fsanitize=implicit-integer-truncation`.
As for the ordering, i'we opted to emit the check **after**
`-fsanitize=implicit-integer-truncation`. At least on these simple 16 test cases,
this results in 1 of the 12 emitted checks being optimized away,
as compared to 0 checks being optimized away if the order is reversed.

This is a clang part.
The compiler-rt part is D50251.

Finishes fixing [[ https://bugs.llvm.org/show_bug.cgi?id=21530 | PR21530 ]], [[ https://bugs.llvm.org/show_bug.cgi?id=37552 | PR37552 ]], [[ https://bugs.llvm.org/show_bug.cgi?id=35409 | PR35409 ]].
Finishes partially fixing [[ https://bugs.llvm.org/show_bug.cgi?id=9821 | PR9821 ]].
Finishes fixing https://github.com/google/sanitizers/issues/940.

Only the bitfield handling is missing.

Reviewers: vsk, rsmith, rjmccall, #sanitizers, erichkeane

Reviewed By: rsmith

Subscribers: chandlerc, filcab, cfe-commits, regehr

Tags: #sanitizers, #clang

Differential Revision: https://reviews.llvm.org/D50250

llvm-svn: 345660
2018-10-30 21:58:56 +00:00
Richard Smith d2e69dfddb PR23833, DR2140: an lvalue-to-rvalue conversion on a glvalue of type
nullptr_t does not access memory.

We now reuse CK_NullToPointer to represent a conversion from a glvalue
of type nullptr_t to a prvalue of nullptr_t where necessary.

llvm-svn: 345562
2018-10-30 02:02:49 +00:00
Bjorn Pettersson b25340236c [Fixed Point Arithmetic] Refactor fixed point casts
Summary:
- Added names for some emitted values (such as "tobool" for
  the result of a cast to boolean).
- Replaced explicit IRBuilder request for doing sext/zext/trunc
  by using CreateIntCast instead.
- Simplify code for emitting satuation into one if-statement
  for clamping to max, and one if-statement for clamping to min.

Reviewers: leonardchan, ebevhan

Reviewed By: leonardchan

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D53707

llvm-svn: 345398
2018-10-26 16:12:12 +00:00
Leonard Chan b4ba467da8 [Fixed Point Arithmetic] Fixed Point to Boolean Cast
This patch is a part of https://reviews.llvm.org/D48456 in an attempt to split
the casting logic up into smaller patches. This contains the code for casting
from fixed point types to boolean types.

Differential Revision: https://reviews.llvm.org/D53308

llvm-svn: 345063
2018-10-23 17:55:35 +00:00
Andrew Savonichev b555b76ed3 [OpenCL][NFC] Unify ZeroToOCL* cast types
Reviewers: Anastasia, yaxunl

Reviewed By: Anastasia

Subscribers: asavonic, cfe-commits

Differential Revision: https://reviews.llvm.org/D52654

llvm-svn: 345038
2018-10-23 15:19:20 +00:00
Leonard Chan 99bda375a1 [Fixed Point Arithmetic] FixedPointCast
This patch is a part of https://reviews.llvm.org/D48456 in an attempt to
split them up. This contains the code for casting between fixed point types
and other fixed point types.

The method for converting between fixed point types is based off the convert()
method in APFixedPoint.

Differential Revision: https://reviews.llvm.org/D50616

llvm-svn: 344530
2018-10-15 16:07:02 +00:00
Roman Lebedev dd403575a2 [clang][ubsan] Split Implicit Integer Truncation Sanitizer into unsigned and signed checks
Summary:
As per IRC disscussion, it seems we really want to have more fine-grained `-fsanitize=implicit-integer-truncation`:
* A check when both of the types are unsigned.
* Another check for the other cases (either one of the types is signed, or both of the types is signed).

This is clang part.
Compiler-rt part is D50902.

Reviewers: rsmith, vsk, Sanitizers

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D50901

llvm-svn: 344230
2018-10-11 09:09:50 +00:00
Stephen Kelly f2ceec4811 Port getLocStart -> getBeginLoc
Reviewers: teemperor!

Subscribers: jholewinski, whisperity, jfb, cfe-commits

Differential Revision: https://reviews.llvm.org/D50350

llvm-svn: 339385
2018-08-09 21:08:08 +00:00
Fangrui Song 6907ce2f8f Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h}

llvm-svn: 338291
2018-07-30 19:24:48 +00:00
Roman Lebedev b69ba22773 [clang][ubsan] Implicit Conversion Sanitizer - integer truncation - clang part
Summary:
C and C++ are interesting languages. They are statically typed, but weakly.
The implicit conversions are allowed. This is nice, allows to write code
while balancing between getting drowned in everything being convertible,
and nothing being convertible. As usual, this comes with a price:

```
unsigned char store = 0;

bool consume(unsigned int val);

void test(unsigned long val) {
  if (consume(val)) {
    // the 'val' is `unsigned long`, but `consume()` takes `unsigned int`.
    // If their bit widths are different on this platform, the implicit
    // truncation happens. And if that `unsigned long` had a value bigger
    // than UINT_MAX, then you may or may not have a bug.

    // Similarly, integer addition happens on `int`s, so `store` will
    // be promoted to an `int`, the sum calculated (0+768=768),
    // and the result demoted to `unsigned char`, and stored to `store`.
    // In this case, the `store` will still be 0. Again, not always intended.
    store = store + 768; // before addition, 'store' was promoted to int.
  }

  // But yes, sometimes this is intentional.
  // You can either make the conversion explicit
  (void)consume((unsigned int)val);
  // or mask the value so no bits will be *implicitly* lost.
  (void)consume((~((unsigned int)0)) & val);
}
```

Yes, there is a `-Wconversion`` diagnostic group, but first, it is kinda
noisy, since it warns on everything (unlike sanitizers, warning on an
actual issues), and second, there are cases where it does **not** warn.
So a Sanitizer is needed. I don't have any motivational numbers, but i know
i had this kind of problem 10-20 times, and it was never easy to track down.

The logic to detect whether an truncation has happened is pretty simple
if you think about it - https://godbolt.org/g/NEzXbb - basically, just
extend (using the new, not original!, signedness) the 'truncated' value
back to it's original width, and equality-compare it with the original value.

The most non-trivial thing here is the logic to detect whether this
`ImplicitCastExpr` AST node is **actually** an implicit conversion, //or//
part of an explicit cast. Because the explicit casts are modeled as an outer
`ExplicitCastExpr` with some `ImplicitCastExpr`'s as **direct** children.
https://godbolt.org/g/eE1GkJ

Nowadays, we can just use the new `part_of_explicit_cast` flag, which is set
on all the implicitly-added `ImplicitCastExpr`'s of an `ExplicitCastExpr`.
So if that flag is **not** set, then it is an actual implicit conversion.

As you may have noted, this isn't just named `-fsanitize=implicit-integer-truncation`.
There are potentially some more implicit conversions to be warned about.
Namely, implicit conversions that result in sign change; implicit conversion
between different floating point types, or between fp and an integer,
when again, that conversion is lossy.

One thing i know isn't handled is bitfields.

This is a clang part.
The compiler-rt part is D48959.

Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=21530 | PR21530 ]], [[ https://bugs.llvm.org/show_bug.cgi?id=37552 | PR37552 ]], [[ https://bugs.llvm.org/show_bug.cgi?id=35409 | PR35409 ]].
Partially fixes [[ https://bugs.llvm.org/show_bug.cgi?id=9821 | PR9821 ]].
Fixes https://github.com/google/sanitizers/issues/940. (other than sign-changing implicit conversions)

Reviewers: rjmccall, rsmith, samsonov, pcc, vsk, eugenis, efriedma, kcc, erichkeane

Reviewed By: rsmith, vsk, erichkeane

Subscribers: erichkeane, klimek, #sanitizers, aaron.ballman, RKSimon, dtzWill, filcab, danielaustin, ygribov, dvyukov, milianw, mclow.lists, cfe-commits, regehr

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D48958

llvm-svn: 338288
2018-07-30 18:58:30 +00:00
Piotr Padlewski 0705829e40 [CodeGenCXX] Emit strip.invariant.group with -fstrict-vtable-pointers
Summary:
Emmiting new intrinsic that strips invariant.groups to make
devirtulization sound, as described in RFC: Devirtualization v2.

Reviewers: rjmccall, rsmith, amharc, kuhar

Subscribers: llvm-commits, cfe-commits

Differential Revision: https://reviews.llvm.org/D47299

Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 336137
2018-07-02 19:21:36 +00:00
Anastasis Grammenos dfe8fe503c [DebugInfo] Inline for without DebugLocation
Summary:
This test is a strip down version of a function inside the
amalgamated sqlite source. When converted to IR clang produces
a phi instruction without debug location.

This patch fixes the above issue.

Differential Revision: https://reviews.llvm.org/D47720

llvm-svn: 335255
2018-06-21 16:53:48 +00:00
Leonard Chan db01c3adc6 [Fixed Point Arithmetic] Fixed Point Precision Bits and Fixed Point Literals
This diff includes the logic for setting the precision bits for each primary fixed point type in the target info and logic for initializing a fixed point literal.

Fixed point literals are declared using the suffixes

```
hr: short _Fract
uhr: unsigned short _Fract
r: _Fract
ur: unsigned _Fract
lr: long _Fract
ulr: unsigned long _Fract
hk: short _Accum
uhk: unsigned short _Accum
k: _Accum
uk: unsigned _Accum
```
Errors are also thrown for illegal literal values

```
unsigned short _Accum u_short_accum = 256.0uhk;   // expected-error{{the integral part of this literal is too large for this unsigned _Accum type}}
```

Differential Revision: https://reviews.llvm.org/D46915

llvm-svn: 335148
2018-06-20 17:19:40 +00:00
Adrian Prantl 9fc8faf9e6 Remove \brief commands from doxygen comments.
This is similar to the LLVM change https://reviews.llvm.org/D46290.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46320

llvm-svn: 331834
2018-05-09 01:00:01 +00:00
Malcolm Parsons fab3680990 Clean carriage returns from lib/ and include/. NFC.
Summary:
Clean carriage returns from lib/ and include/. NFC.
(I have to make this change locally in order for `git diff` to show sane output after I edit a file, so I might as well ask for it to be committed. I don't have commit privs myself.)
(Without this patch, `git rebase`ing any change involving SemaDeclCXX.cpp is a real nightmare. :( So while I have no right to ask for this to be committed, geez would it make my workflow easier if it were.)

Here's the command I used to reformat things. (Requires bash and OSX/FreeBSD sed.)

    git grep -l $'\r' lib include | xargs sed -i -e $'s/\r//'
    find lib include -name '*-e' -delete

Reviewers: malcolm.parsons

Reviewed By: malcolm.parsons

Subscribers: emaste, krytarowski, cfe-commits

Differential Revision: https://reviews.llvm.org/D45591

Patch by Arthur O'Dwyer.

llvm-svn: 330112
2018-04-16 08:31:08 +00:00
Akira Hatanaka 797afe3a4e [CodeGen] Ignore OpaqueValueExprs that are unique references to their
source expressions when iterating over a PseudoObjectExpr's semantic
subexpression list.

Previously the loop in emitPseudoObjectExpr would emit the IR for each
OpaqueValueExpr that was in a PseudoObjectExpr's semantic-form
expression list and use the result when the OpaqueValueExpr later
appeared in other expressions. This caused an assertion failure when
AggExprEmitter tried to copy the result of an OpaqueValueExpr and the
copied type didn't have trivial copy/move constructors or assignment
operators.

This patch adds flag IsUnique to OpaqueValueExpr which indicates it is a
unique reference to its source expression (it is not used in multiple
places). The loop in emitPseudoObjectExpr ignores OpaqueValueExprs that
are unique and CodeGen visitors simply traverse the source expressions
of such OpaqueValueExprs.

rdar://problem/34363596

Differential Revision: https://reviews.llvm.org/D39562

llvm-svn: 327939
2018-03-20 01:47:58 +00:00
Sander de Smalen 891af03a55 Recommit rL323952: [DebugInfo] Enable debug information for C99 VLA types.
Fixed build issue when building with g++-4.8 (specialization after instantiation).

llvm-svn: 324173
2018-02-03 13:55:59 +00:00
Sander de Smalen 4e9a1264dd Reverting patch rL323952 due to build errors that I
haven't encountered in local builds.

llvm-svn: 323956
2018-02-01 12:27:13 +00:00
Sander de Smalen 17c4633e7f [DebugInfo] Enable debug information for C99 VLA types
Summary:
This patch enables debugging of C99 VLA types by generating more precise
LLVM Debug metadata, using the extended DISubrange 'count' field that
takes a DIVariable.
    
This should implement:
  Bug 30553: Debug info generated for arrays is not what GDB expects (not as good as GCC's)
https://bugs.llvm.org/show_bug.cgi?id=30553

Reviewers: echristo, aprantl, dexonsmith, clayborg, pcc, kristof.beyls, dblaikie

Reviewed By: aprantl

Subscribers: jholewinski, schweitz, davide, fhahn, JDevlieghere, cfe-commits

Differential Revision: https://reviews.llvm.org/D41698

llvm-svn: 323952
2018-02-01 11:25:10 +00:00
Aaron Ballman a503855906 Track in the AST whether the operand to a UnaryOperator can overflow and then use that logic when evaluating constant expressions and emitting codegen.
llvm-svn: 322074
2018-01-09 13:07:03 +00:00
Richard Smith c70f1d63f8 [c++20] P0515R3: Parsing support and basic AST construction for operator <=>.
Adding the new enumerator forced a bunch more changes into this patch than I
would have liked. The -Wtautological-compare warning was extended to properly
check the new comparison operator, clang-format needed updating because it uses
precedence levels as weights for determining where to break lines (and several
operators increased their precedence levels with this change), thread-safety
analysis needed changes to build its own IL properly for the new operator.

All "real" semantic checking for this operator has been deferred to a future
patch. For now, we use the relational comparison rules and arbitrarily give
the builtin form of the operator a return type of 'void'.

llvm-svn: 320707
2017-12-14 15:16:18 +00:00
Akira Hatanaka 502775a2ee [CodeGen][X86] Fix handling of __fp16 vectors.
This commit fixes a bug in IRGen where it generates completely broken
code for __fp16 vectors on X86. For example when the following code is
compiled:

half4 hv0, hv1, hv2; // these are vectors of __fp16.

void foo221() {
  hv0 = hv1 + hv2;
}

clang generates the following IR, in which two i16 vectors are added:

@hv1 = common global <4 x i16> zeroinitializer, align 8
@hv2 = common global <4 x i16> zeroinitializer, align 8
@hv0 = common global <4 x i16> zeroinitializer, align 8

define void @foo221() {
  %0 = load <4 x i16>, <4 x i16>* @hv1, align 8
  %1 = load <4 x i16>, <4 x i16>* @hv2, align 8
  %add = add <4 x i16> %0, %1
  store <4 x i16> %add, <4 x i16>* @hv0, align 8
  ret void
}

To fix the bug, this commit uses the code committed in r314056, which
modified clang to promote and truncate __fp16 vectors to and from float
vectors in the AST. It also fixes another IRGen bug where a short value
is assigned to an __fp16 variable without any integer-to-floating-point
conversion, as shown in the following example:

__fp16 a;
short b;

void foo1() {
  a = b;
}

@b = common global i16 0, align 2
@a = common global i16 0, align 2

define void @foo1() #0 {
  %0 = load i16, i16* @b, align 2
  store i16 %0, i16* @a, align 2
  ret void
}

rdar://problem/20625184

Differential Revision: https://reviews.llvm.org/D40112

llvm-svn: 320215
2017-12-09 00:02:37 +00:00