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[SYCL] Report Compiling error for recursion in SYCL kernel #3390

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Merged
merged 7 commits into from
Apr 8, 2021
Merged

[SYCL] Report Compiling error for recursion in SYCL kernel #3390

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f3e005d
Report Compiling error for recursion in SYCL kernel
jinge90 Mar 22, 2021
4968d31
Merge remote-tracking branch 'origin/sycl' into compiling_error_for_r…
jinge90 Mar 23, 2021
1d53420
Support Recursion in ESIMD kernel
jinge90 Mar 31, 2021
68c5111
clang format
jinge90 Apr 1, 2021
971f2e2
Merge remote-tracking branch 'origin/sycl' into compiling_error_for_r…
jinge90 Apr 1, 2021
9b17f65
Merge remote-tracking branch 'origin/sycl' into compiling_error_for_r…
jinge90 Apr 2, 2021
4a3eb37
revert esimd kernel recursion support
jinge90 Apr 2, 2021
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3 changes: 0 additions & 3 deletions clang/include/clang/Basic/DiagnosticSemaKinds.td
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Original file line number Diff line number Diff line change
Expand Up @@ -11293,9 +11293,6 @@ def warn_sycl_implicit_decl
"declaration for a kernel type name; your program may not "
"be portable">,
InGroup<SyclStrict>, ShowInSystemHeader, DefaultIgnore;
def warn_sycl_restrict_recursion
: Warning<"SYCL kernel cannot call a recursive function">,
InGroup<SyclStrict>, DefaultError;
def err_ivdep_duplicate_arg : Error<
"duplicate argument to 'ivdep'; attribute requires one or both of a safelen "
"and array">;
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3 changes: 2 additions & 1 deletion clang/lib/Sema/SemaSYCL.cpp
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Expand Up @@ -376,7 +376,8 @@ class MarkDeviceFunction : public RecursiveASTVisitor<MarkDeviceFunction> {
// all functions used by kernel have already been parsed and have
// definitions.
if (RecursiveSet.count(Callee) && !ConstexprDepth) {
SemaRef.Diag(e->getExprLoc(), diag::warn_sycl_restrict_recursion);
SemaRef.Diag(e->getExprLoc(), diag::err_sycl_restrict)
<< Sema::KernelCallRecursiveFunction;
SemaRef.Diag(Callee->getSourceRange().getBegin(),
diag::note_sycl_recursive_function_declared_here)
<< Sema::KernelCallRecursiveFunction;
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2 changes: 1 addition & 1 deletion clang/test/SemaSYCL/restrict-recursion3.cpp
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Expand Up @@ -34,7 +34,7 @@ template <typename name, typename Func>
__attribute__((sycl_kernel)) void kernel_single_task2(const Func &kernelFunc) {
// expected-note@+1 {{called by 'kernel_single_task2}}
kernelFunc();
// expected-warning@+1 2{{SYCL kernel cannot call a recursive function}}
// expected-error@+1 2{{SYCL kernel cannot call a recursive function}}
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Why is this diagnostic issued twice?

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I'm still curious about this.

kernel_single_task2<name, Func>(kernelFunc);
}

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4 changes: 2 additions & 2 deletions clang/test/SemaSYCL/restrict-recursion4.cpp
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Expand Up @@ -10,7 +10,7 @@ int fib(int n) {

// expected-note@+1 2{{function implemented using recursion declared here}}
void kernel2(void) {
// expected-warning@+1 {{SYCL kernel cannot call a recursive function}}
// expected-error@+1 {{SYCL kernel cannot call a recursive function}}
kernel2();
}

Expand All @@ -24,7 +24,7 @@ void *operator new(size_t);
void usage2(myFuncDef functionPtr) {
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Could it be possible to add a test like

void kernel3(void) {
  if constexpr (false)
    kernel3();
  if (false)
    kernel3();
}

and verify it does not fire?

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Hi, @keryell
I am afraid current implementation can't handle this as we are analyzing the call graph to recognize all recursions and don't know whether the recursive call is in a "dead" branch.
Thanks very much.

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I think it's reasonable to not diagnose recursion in dead branches, but we should still have test coverage (with comments) that show we've explicitly considered this case.

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This comment is still unaddressed, btw.

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@AaronBallman :Note that my patch adds a test for this. See: #3475

// expected-error@+1 {{SYCL kernel cannot allocate storage}}
int *ip = new int;
// expected-warning@+1 {{SYCL kernel cannot call a recursive function}}
// expected-error@+1 {{SYCL kernel cannot call a recursive function}}
kernel2();
}

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