1415 Commits

Author SHA1 Message Date
David Bolvansky
aaea76ba02 [Diagnostics] Emit better -Wbool-operation's warning message if we known that the result is always true
llvm-svn: 373973
2019-10-07 21:57:03 +00:00
Simon Pilgrim
dc4d908d6e Sema - silence static analyzer getAs<> null dereference warnings. NFCI.
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<> directly and if not assert will fire for us.

llvm-svn: 373911
2019-10-07 14:25:46 +00:00
Yuanfang Chen
442ddffe13 [clang] fix a typo from r372531
Reviewers: xbolva00

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D68482

llvm-svn: 373792
2019-10-04 21:37:20 +00:00
Erik Pilkington
f7766b1ed4 [Sema] Split out -Wformat-type-confusion from -Wformat-pedantic
The warnings now in -Wformat-type-confusion don't align with how we interpret
'pedantic' in clang, and don't belong in -pedantic.

Differential revision: https://reviews.llvm.org/D67775

llvm-svn: 373774
2019-10-04 19:20:27 +00:00
Simon Pilgrim
1cd399c915 Silence static analyzer getAs<RecordType> null dereference warnings. NFCI.
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<RecordType> directly and if not assert will fire for us.

llvm-svn: 373584
2019-10-03 11:22:48 +00:00
Simon Pilgrim
e0712019f2 Silence static analyzer getAs<VectorType> null dereference warnings. NFCI.
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<VectorType> directly and if not assert will fire for us.

llvm-svn: 373478
2019-10-02 15:31:25 +00:00
David Bolvansky
471910d754 [Diagnostics] Warn if enumeration type mismatch in conditional expression
Summary:
- Useful warning
- GCC compatibility (GCC warns in C++ mode)

Reviewers: rsmith, aaron.ballman

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67919

llvm-svn: 373252
2019-09-30 19:55:50 +00:00
David Bolvansky
e52ed1e80c [NFC] Strenghten preconditions for warning
llvm-svn: 372775
2019-09-24 20:10:57 +00:00
David Bolvansky
275e4df115 [Diagnostics] Handle tautological left shifts in boolean context
llvm-svn: 372749
2019-09-24 13:14:18 +00:00
David Bolvansky
849fd28cf0 [Diagnostics] Do not diagnose unsigned shifts in boolean context (-Wint-in-bool-context)
I was looking at old GCC's patch. Current "trunk" version avoids warning for unsigned case, GCC warns only for signed shifts.

llvm-svn: 372708
2019-09-24 09:14:33 +00:00
Michael Liao
566b3164c5 [Sema] Fix the atomic expr rebuilding order.
Summary:
- Rearrange the atomic expr order to the API order when rebuilding
  atomic expr during template instantiation.

Reviewers: erichkeane

Subscribers: jfb, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67924

llvm-svn: 372640
2019-09-23 18:48:06 +00:00
David Bolvansky
84ea41fd17 [Diagnostics] Warn if '<<' in bool context with -Wint-in-bool-context (GCC compatibility)
Extracted from D63082, addressed review comments related to a warning message.

llvm-svn: 372612
2019-09-23 14:21:08 +00:00
David Bolvansky
fb218170b4 [Diagnostics] Warn if ?: with integer constants always evaluates to true
Extracted from D63082. GCC has this warning under -Wint-in-bool-context, but as noted in the D63082's review, we should put it under TautologicalConstantCompare.

llvm-svn: 372531
2019-09-22 22:00:48 +00:00
Yonghong Song
91d5c2a035 [CLANG][BPF] permit any argument type for __builtin_preserve_access_index()
Commit c15aa241f821 ("[CLANG][BPF] change __builtin_preserve_access_index()
signature") changed the builtin function signature to
  PointerT __builtin_preserve_access_index(PointerT ptr)
with a pointer type as the argument/return type, where argument and
return types must be the same.

There is really no reason for this constraint. The builtin just
presented a code region so that IR builtins
  __builtin_{array, struct, union}_preserve_access_index
can be applied.

This patch removed the pointer type restriction to permit any
argument type as long as it is permitted by the compiler.

Differential Revision: https://reviews.llvm.org/D67883

llvm-svn: 372516
2019-09-22 17:33:48 +00:00
Erich Keane
830909b97a Ensure AtomicExpr goes through SEMA checking after TreeTransform
RebuildAtomicExpr was skipping doing semantic analysis which broke in
the cases where the expressions were not dependent. This resulted in the
ImplicitCastExpr from an array to a pointer being lost, causing a crash
in IR CodeGen.

Differential Revision: https://reviews.llvm.org/D67854

llvm-svn: 372422
2019-09-20 19:17:31 +00:00
Yonghong Song
c15aa241f8 [CLANG][BPF] change __builtin_preserve_access_index() signature
The clang intrinsic __builtin_preserve_access_index() currently
has signature:
  const void * __builtin_preserve_access_index(const void * ptr)

This may cause compiler warning when:
  - parameter type is "volatile void *" or "const volatile void *", or
  - the assign-to type of the intrinsic does not have "const" qualifier.
Further, this signature does not allow dereference of the
builtin result pointer as it is a "const void *" type, which
adds extra step for the user to do type casting.

Let us change the signature to:
  PointerT __builtin_preserve_access_index(PointerT ptr)
such that the result and argument types are the same.
With this, directly dereferencing the builtin return value
becomes possible.

Differential Revision: https://reviews.llvm.org/D67734

llvm-svn: 372294
2019-09-19 02:59:43 +00:00
Erik Pilkington
5741d19f04 [Sema] Suppress -Wformat diagnostics for bool types when printed using %hhd
Also, add a diagnostic under -Wformat for printing a boolean value as a
character.

rdar://54579473

Differential revision: https://reviews.llvm.org/D66856

llvm-svn: 372247
2019-09-18 19:05:14 +00:00
Erik Pilkington
5c62152275 [Sema] Split of versions of -Wimplicit-{float,int}-conversion for Objective-C BOOL
Also, add a diagnostic group, -Wobjc-signed-char-bool, to control all these
related diagnostics.

rdar://51954400

Differential revision: https://reviews.llvm.org/D67559

llvm-svn: 372183
2019-09-17 21:11:51 +00:00
Craig Topper
ce2cb0f09e [X86] Allow _MM_FROUND_CUR_DIRECTION and _MM_FROUND_NO_EXC to be used together on instructions that only support SAE and not embedded rounding.
Current for SAE instructions we only allow _MM_FROUND_CUR_DIRECTION(bit 2) or _MM_FROUND_NO_EXC(bit 3) to be used as the immediate passed to the inrinsics. But these instructions don't perform rounding so _MM_FROUND_CUR_DIRECTION is just sort of a default placeholder when you don't want to suppress exceptions. Using _MM_FROUND_NO_EXC by itself is really bit equivalent to (_MM_FROUND_NO_EXC | _MM_FROUND_TO_NEAREST_INT) since _MM_FROUND_TO_NEAREST_INT is 0. Since we aren't rounding on these instructions we should also accept (_MM_FROUND_CUR_DIRECTION | _MM_FROUND_NO_EXC) as equivalent to (_MM_FROUND_NO_EXC). icc allows this, but gcc does not.

Differential Revision: https://reviews.llvm.org/D67289

llvm-svn: 371430
2019-09-09 17:48:05 +00:00
David Bolvansky
fd07568074 [Diagnostics] Refactor code for -Wsizeof-pointer-div, catch more cases; also add -Wsizeof-array-div
Previously, -Wsizeof-pointer-div failed to catch:
const int *r;
sizeof(r) / sizeof(int);

Now fixed.
Also introduced -Wsizeof-array-div which catches bugs like:
sizeof(r) / sizeof(short);

(Array element type does not match type of sizeof operand).

llvm-svn: 371222
2019-09-06 16:12:48 +00:00
Jinsong Ji
a71c199f82 [PowerPC][Altivec][Clang] Check compile-time constant for vec_dst*
Summary:
This is follow up of https://reviews.llvm.org/D66699.
We might get ISEL ICE if we call vec_dss with non const 3rd arg.

```
Cannot select: intrinsic %llvm.ppc.altivec.dst
```

We should check the constraints in clang and generate better error
messages.

Reviewers: nemanjai, hfinkel, echristo, #powerpc, wuzish

Reviewed By: #powerpc, wuzish

Subscribers: wuzish, kbarton, MaskRay, shchenz, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66748

llvm-svn: 370912
2019-09-04 15:22:26 +00:00
Jinsong Ji
5309189d9b [PowerPC][Altivec] Fix constant argument for vec_dss
Summary:
This is similar to vec_ct* in https://reviews.llvm.org/rL304205.

The argument must be a constant, otherwise instruction selection
will fail. always_inline is not enough for isel to always fold
everything away at -O0.

The fix is to turn the function into macros in altivec.h.

Fixes https://bugs.llvm.org/show_bug.cgi?id=43072

Reviewers: nemanjai, hfinkel, #powerpc, wuzish

Reviewed By: #powerpc, wuzish

Subscribers: wuzish, kbarton, MaskRay, shchenz, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66699

llvm-svn: 370902
2019-09-04 14:01:47 +00:00
Sven van Haastregt
a280b63ead [OpenCL] Fix diagnosing enqueue_kernel call with too few args
The err_typecheck_call_too_few_args diagnostic takes arguments, but
none were provided causing clang to crash when attempting to diagnose
an enqueue_kernel call with too few arguments.

Fixes llvm.org/PR42045

Differential Revision: https://reviews.llvm.org/D66883

llvm-svn: 370322
2019-08-29 10:21:06 +00:00
Nathan Huckleberry
cc01d6421f [Sema] Don't warn on printf('%hd', [char]) (PR41467)
Summary: Link: https://bugs.llvm.org/show_bug.cgi?id=41467

Reviewers: rsmith, nickdesaulniers, aaron.ballman, lebedev.ri

Reviewed By: nickdesaulniers, aaron.ballman, lebedev.ri

Subscribers: lebedev.ri, nickdesaulniers, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D66186

llvm-svn: 369791
2019-08-23 18:01:57 +00:00
Erik Pilkington
aa3855694f [Sema][ObjC] Fix a -Wformat false positive with localizedStringForKey
Only honour format_arg attributes on -[NSBundle localizedStringForKey] when its
argument has a format specifier in it, otherwise its likely to just be a key to
fetch localized strings.

Fixes rdar://23622446

Differential revision: https://reviews.llvm.org/D27165

llvm-svn: 368878
2019-08-14 16:57:11 +00:00
Dmitri Gribenko
a5ef73cb4b Revert "Fix crash on switch conditions of non-integer types in templates"
This reverts commit r368706. It broke ClangTidy tests.

llvm-svn: 368738
2019-08-13 19:07:28 +00:00
Elizabeth Andrews
76945821b9 Fix crash on switch conditions of non-integer types in templates
Clang currently crashes for switch statements inside a template when
the condition is a non-integer field. The crash is due to incorrect
type-dependency of field. Type-dependency of member expressions is
currently set based on the containing class. This patch changes this for
'members of the current instantiation' to set the type dependency based
on the member's type instead.

A few lit tests started to fail once I applied this patch because errors
are now diagnosed earlier (does not wait till instantiation). I've modified
these tests in this patch as well.

Patch fixes PR#40982

Differential Revision: https://reviews.llvm.org/D61027

llvm-svn: 368706
2019-08-13 15:53:19 +00:00
Ziang Wan
87b668befe [Sema] Enable -Wimplicit-float-conversion for integral to floating point precision loss
Issue an warning when the code tries to do an implicit int -> float
conversion, where the float type ha a narrower significant than the
float type.

The new warning is controlled by flag -Wimplicit-int-float-conversion,
under -Wimplicit-float-conversion and -Wconversion. It is also silenced
when c++11 narrowing warning is issued.

Differential Revision: https://reviews.llvm.org/D64666

llvm-svn: 367497
2019-08-01 00:16:43 +00:00
Momchil Velikov
a36d31478c [AArch64] Add support for Transactional Memory Extension (TME)
Re-commit r366322 after some fixes

TME is a future architecture technology, documented in

  https://developer.arm.com/architectures/cpu-architecture/a-profile/exploration-tools
  https://developer.arm.com/docs/ddi0601/a

More about the future architectures:

  https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/new-technologies-for-the-arm-a-profile-architecture

This patch adds support for the TME instructions TSTART, TTEST, TCOMMIT, and
TCANCEL and the target feature/arch extension "tme".

It also implements TME builtin functions, defined in ACLE Q2 2019
(https://developer.arm.com/docs/101028/latest)

Differential Revision: https://reviews.llvm.org/D64416

Patch by Javed Absar and Momchil Velikov

llvm-svn: 367428
2019-07-31 12:52:17 +00:00
George Burgess IV
9d045a5c1e [Sema] add -Walloca to flag uses of alloca
This CL adds an optional warning to diagnose uses of the
`__builtin_alloca` family of functions. The use of these functions is
discouraged by many, so it seems like a good idea to allow clang to warn
about it.

Patch by Elaina Guan!

Differential Revision: https://reviews.llvm.org/D64883

llvm-svn: 367067
2019-07-25 22:23:40 +00:00
Petr Hosek
f55f51b7be Revert "[Sema] Enable -Wimplicit-float-conversion for integral to floating point precision loss"
This reverts commit r366972 which broke the following tests:

  Clang :: CXX/dcl.decl/dcl.init/dcl.init.list/p7-0x.cpp
  Clang :: CXX/dcl.decl/dcl.init/dcl.init.list/p7-cxx11-nowarn.cpp

llvm-svn: 366979
2019-07-25 03:11:49 +00:00
Ziang Wan
2028d97d09 [Sema] Enable -Wimplicit-float-conversion for integral to floating point precision loss
Issue an warning when the code tries to do an implicit int -> float
conversion, where the float type ha a narrower significant than the
float type.

The new warning is controlled by flag -Wimplicit-int-float-conversion,
under -Wimplicit-float-conversion and -Wconversion.

Differential Revision: https://reviews.llvm.org/D64666

llvm-svn: 366972
2019-07-25 00:32:50 +00:00
Momchil Velikov
0e2b74a2b0 Revert [AArch64] Add support for Transactional Memory Extension (TME)
This reverts r366322 (git commit 4b8da3a503e434ddbc08ecf66582475765f449bc)

llvm-svn: 366355
2019-07-17 17:43:32 +00:00
Momchil Velikov
4b8da3a503 [AArch64] Add support for Transactional Memory Extension (TME)
TME is a future architecture technology, documented in

https://developer.arm.com/architectures/cpu-architecture/a-profile/exploration-tools
https://developer.arm.com/docs/ddi0601/a

More about the future architectures:

https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/new-technologies-for-the-arm-a-profile-architecture

This patch adds support for the TME instructions TSTART, TTEST, TCOMMIT, and
TCANCEL and the target feature/arch extension "tme".

It also implements TME builtin functions, defined in ACLE Q2 2019
(https://developer.arm.com/docs/101028/latest)

Patch by Javed Absar and Momchil Velikov

Differential Revision: https://reviews.llvm.org/D64416

llvm-svn: 366322
2019-07-17 13:23:27 +00:00
Rui Ueyama
49a3ad21d6 Fix parameter name comments using clang-tidy. NFC.
This patch applies clang-tidy's bugprone-argument-comment tool
to LLVM, clang and lld source trees. Here is how I created this
patch:

$ git clone https://github.com/llvm/llvm-project.git
$ cd llvm-project
$ mkdir build
$ cd build
$ cmake -GNinja -DCMAKE_BUILD_TYPE=Debug \
    -DLLVM_ENABLE_PROJECTS='clang;lld;clang-tools-extra' \
    -DCMAKE_EXPORT_COMPILE_COMMANDS=On -DLLVM_ENABLE_LLD=On \
    -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ../llvm
$ ninja
$ parallel clang-tidy -checks='-*,bugprone-argument-comment' \
    -config='{CheckOptions: [{key: StrictMode, value: 1}]}' -fix \
    ::: ../llvm/lib/**/*.{cpp,h} ../clang/lib/**/*.{cpp,h} ../lld/**/*.{cpp,h}

llvm-svn: 366177
2019-07-16 04:46:31 +00:00
Ulrich Weigand
b98bf60ef7 [SystemZ] Add support for new cpu architecture - arch13
This patch series adds support for the next-generation arch13
CPU architecture to the SystemZ backend.

This includes:
- Basic support for the new processor and its features.
- Support for low-level builtins mapped to new LLVM intrinsics.
- New high-level intrinsics in vecintrin.h.
- Indicate support by defining  __VEC__ == 10303.

Note: No currently available Z system supports the arch13
architecture.  Once new systems become available, the
official system name will be added as supported -march name.

llvm-svn: 365933
2019-07-12 18:14:51 +00:00
Erik Pilkington
abffae3a56 [ObjC] Add a warning for implicit conversions of a constant non-boolean value to BOOL
rdar://51954400

Differential revision: https://reviews.llvm.org/D63912

llvm-svn: 365518
2019-07-09 17:29:40 +00:00
Yonghong Song
048493f882 [BPF] Preserve debuginfo array/union/struct type/access index
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

If using these intrinsics blindly, i.e., transforming all GEPs
to these intrinsics and later on reducing them to GEPs, we have
seen up to 7% more instructions generated. To avoid such an overhead,
a clang builtin is proposed:
  base = __builtin_preserve_access_index(base)
such that user wraps to-be-relocated GEPs in this builtin
and preserve_*_access_index intrinsics only apply to
those GEPs. Such a buyin will prevent performance degradation
if people do not use CO-RE, even for programs which use
bpf_probe_read().

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:
  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61809

llvm-svn: 365438
2019-07-09 04:21:50 +00:00
Yonghong Song
e085b40e9c Revert "[BPF] Preserve debuginfo array/union/struct type/access index"
This reverts commit r365435.

Forgot adding the Differential Revision link. Will add to the
commit message and resubmit.

llvm-svn: 365436
2019-07-09 04:15:12 +00:00
Yonghong Song
f21eeafcd9 [BPF] Preserve debuginfo array/union/struct type/access index
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

If using these intrinsics blindly, i.e., transforming all GEPs
to these intrinsics and later on reducing them to GEPs, we have
seen up to 7% more instructions generated. To avoid such an overhead,
a clang builtin is proposed:
  base = __builtin_preserve_access_index(base)
such that user wraps to-be-relocated GEPs in this builtin
and preserve_*_access_index intrinsics only apply to
those GEPs. Such a buyin will prevent performance degradation
if people do not use CO-RE, even for programs which use
bpf_probe_read().

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:
  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

Signed-off-by: Yonghong Song <yhs@fb.com>
llvm-svn: 365435
2019-07-09 04:04:21 +00:00
Erik Pilkington
fa591c370d [ObjC] Add a -Wtautological-compare warning for BOOL
On macOS, BOOL is a typedef for signed char, but it should never hold a value
that isn't 1 or 0. Any code that expects a different value in their BOOL should
be fixed.

rdar://51954400

Differential revision: https://reviews.llvm.org/D63856

llvm-svn: 365408
2019-07-08 23:42:52 +00:00
Fangrui Song
7264a474b7 Change std::{lower,upper}_bound to llvm::{lower,upper}_bound or llvm::partition_point. NFC
llvm-svn: 365006
2019-07-03 08:13:17 +00:00
Gauthier Harnisch
0bb4d46b2b [clang] perform semantic checking in constant context
Summary:
Since the addition of __builtin_is_constant_evaluated the result of an expression can change based on whether it is evaluated in constant context. a lot of semantic checking performs evaluations with out specifying context. which can lead to wrong diagnostics.
for example:
```
constexpr int i0 = (long long)__builtin_is_constant_evaluated() * (1ll << 33); //#1
constexpr int i1 = (long long)!__builtin_is_constant_evaluated() * (1ll << 33); //#2
```
before the patch, #2 was diagnosed incorrectly and #1 wasn't diagnosed.
after the patch #1 is diagnosed as it should and #2 isn't.

Changes:
 - add a flag to Sema to passe in constant context mode.
 - in SemaChecking.cpp calls to Expr::Evaluate* are now done in constant context when they should.
 - in SemaChecking.cpp diagnostics for UB are not checked for in constant context because an error will be emitted by the constant evaluator.
 - in SemaChecking.cpp diagnostics for construct that cannot appear in constant context are not checked for in constant context.
 - in SemaChecking.cpp diagnostics on constant expression are always emitted because constant expression are always evaluated.
 - semantic checking for initialization of constexpr variables is now done in constant context.
 - adapt test that were depending on warning changes.
 - add test.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62009

llvm-svn: 363488
2019-06-15 08:32:56 +00:00
Craig Topper
9967a6c60a [X86] Add checks that immediate for reducesd/ss fits in 8-bits.
llvm-svn: 363472
2019-06-14 23:23:19 +00:00
Richard Smith
715f7a1bd0 For DR712: store on a DeclRefExpr whether it constitutes an odr-use.
Begin restructuring to support the forms of non-odr-use reference
permitted by DR712.

llvm-svn: 363086
2019-06-11 17:50:32 +00:00
Simon Atanasyan
c7f0b33fa5 [mips] Check argument for __builtin_msa_ctcmsa / __builtin_msa_cfcmsa
The `__builtin_msa_ctcmsa` and `__builtin_msa_cfcmsa` builtins are mapped
to the `ctcmsa` and `cfcmsa` instructions respectively. While MSA
control registers have indexes in 0..7 range, the instructions accept
register index in 0..31 range [1].

[1] MIPS Architecture for Programmers Volume IV-j:
    The MIPS64 SIMD Architecture Module
https://www.mips.com/?do-download=the-mips64-simd-architecture-module

llvm-svn: 361967
2019-05-29 14:59:32 +00:00
Craig Topper
902f649217 [X86] Fix the Sema checks for getmant builtins to only allow 4 and 8 for rounding immediates.
These don't support embedded rounding so we shouldn't be setting HasRC. That way we only
allow current direction and suppress all exceptions.

llvm-svn: 361897
2019-05-28 23:26:22 +00:00
Richard Smith
255b85f03c Split ActOnCallExpr into an ActOnCallExpr to be called by the parser,
and a BuildCallExpr to be called internally within Sema to build /
rebuild calls.

llvm-svn: 360217
2019-05-08 01:36:36 +00:00
Richard Smith
7d02ca4878 Use DiagRuntimeBehavior for -Wunsequenced to weed out false positives
where either the modification or the other access is unreachable.

This reverts r359984 (which reverted r359962). The bug in clang-tidy's
test suite exposed by the original commit was fixed in r360009.

llvm-svn: 360010
2019-05-06 04:14:01 +00:00
Simon Pilgrim
4c3fbbf635 Revert rL359962 : Use DiagRuntimeBehavior for -Wunsequenced to weed out false positives
where either the modification or the other access is unreachable.
........
Try to fix buildbots

llvm-svn: 359984
2019-05-05 17:10:05 +00:00