This new JIT event listener supports generating profiling data for
the linux 'perf' profiling tool, allowing it to generate function and
instruction level profiles.
Currently this functionality is not enabled by default, but must be
enabled with LLVM_USE_PERF=yes. Given that the listener has no
dependencies, it might be sensible to enable by default once the
initial issues have been shaken out.
I followed existing precedent in registering the listener by default
in lli. Should there be a decision to enable this by default on linux,
that should probably be changed.
Please note that until https://reviews.llvm.org/D47343 is resolved,
using this functionality with mcjit rather than orcjit will not
reliably work.
Disregarding the previous comment, here's an example:
$ cat /tmp/expensive_loop.c
bool stupid_isprime(uint64_t num)
{
if (num == 2)
return true;
if (num < 1 || num % 2 == 0)
return false;
for(uint64_t i = 3; i < num / 2; i+= 2) {
if (num % i == 0)
return false;
}
return true;
}
int main(int argc, char **argv)
{
int numprimes = 0;
for (uint64_t num = argc; num < 100000; num++)
{
if (stupid_isprime(num))
numprimes++;
}
return numprimes;
}
$ clang -ggdb -S -c -emit-llvm /tmp/expensive_loop.c -o
/tmp/expensive_loop.ll
$ perf record -o perf.data -g -k 1 ./bin/lli -jit-kind=mcjit /tmp/expensive_loop.ll 1
$ perf inject --jit -i perf.data -o perf.jit.data
$ perf report -i perf.jit.data
- 92.59% lli jitted-5881-2.so [.] stupid_isprime
stupid_isprime
main
llvm::MCJIT::runFunction
llvm::ExecutionEngine::runFunctionAsMain
main
__libc_start_main
0x4bf6258d4c544155
+ 0.85% lli ld-2.27.so [.] do_lookup_x
And line-level annotations also work:
│ for(uint64_t i = 3; i < num / 2; i+= 2) {
│1 30: movq $0x3,-0x18(%rbp)
0.03 │1 38: mov -0x18(%rbp),%rax
0.03 │ mov -0x10(%rbp),%rcx
│ shr $0x1,%rcx
3.63 │ ┌──cmp %rcx,%rax
│ ├──jae 6f
│ │ if (num % i == 0)
0.03 │ │ mov -0x10(%rbp),%rax
│ │ xor %edx,%edx
89.00 │ │ divq -0x18(%rbp)
│ │ cmp $0x0,%rdx
0.22 │ │↓ jne 5f
│ │ return false;
│ │ movb $0x0,-0x1(%rbp)
│ │↓ jmp 73
│ │ }
3.22 │1 5f:│↓ jmp 61
│ │ for(uint64_t i = 3; i < num / 2; i+= 2) {
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D44892
llvm-svn: 337789
deprecating SymbolResolver and AsynchronousSymbolQuery.
Both lookup overloads take a VSO search order to perform the lookup. The first
overload is non-blocking and takes OnResolved and OnReady callbacks. The second
is blocking, takes a boolean flag to indicate whether to wait until all symbols
are ready, and returns a SymbolMap. Both overloads take a RegisterDependencies
function to register symbol dependencies (if any) on the query.
llvm-svn: 337595
This discards the unresolved symbols set and returns the flags map directly
(rather than mutating it via the first argument).
The unresolved symbols result made it easy to chain lookupFlags calls, but such
chaining should be rare to non-existant (especially now that symbol resolvers
are being deprecated) so the simpler method signature is preferable.
llvm-svn: 337594
A search order is a list of VSOs to be searched linearly to find symbols. Each
VSO now has a search order that will be used when fixing up definitions in that
VSO. Each VSO's search order defaults to just that VSO itself.
This is a first step towards removing symbol resolvers from ORC altogether. In
practice symbol resolvers tended to be used to implement a search order anyway,
sometimes with additional programatic generation of symbols. Now that VSOs
support programmatic generation of definitions via fallback generators, search
orders provide a cleaner way to achieve the desired effect (while removing a lot
of boilerplate).
llvm-svn: 337593
delegate method (and unit test).
The name 'replace' better captures what the old delegate method did: it
returned materialization responsibility for a set of symbols to the VSO.
The new delegate method delegates responsibility for a set of symbols to a new
MaterializationResponsibility instance. This can be used to split responsibility
between multiple threads, or multiple materialization methods.
llvm-svn: 336603
Summary:
CompileOnDemandLayer.cpp uses function in these libraries, and builds
with `-DSHARED_LIB=ON` fail without this.
Reviewers: lhames
Subscribers: mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D48995
llvm-svn: 336389
writing them to a buffer and re-loading them.
Also introduces a multithreaded variant of SimpleCompiler
(MultiThreadedSimpleCompiler) for compiling IR concurrently on multiple
threads.
These changes are required to JIT IR on multiple threads correctly.
No test case yet. I will be looking at how to modify LLI / LLJIT to test
multithreaded JIT support soon.
llvm-svn: 336385
The verifier identified several modules that were broken due to incorrect
linkage on declarations. To fix this, CompileOnDemandLayer2::extractFunction
has been updated to change decls to external linkage.
llvm-svn: 336150
LLJIT is a prefabricated ORC based JIT class that is meant to be the go-to
replacement for MCJIT. Unlike OrcMCJITReplacement (which will continue to be
supported) it is not API or bug-for-bug compatible, but targets the same
use cases: Simple, non-lazy compilation and execution of LLVM IR.
LLLazyJIT extends LLJIT with support for function-at-a-time lazy compilation,
similar to what was provided by LLVM's original (now long deprecated) JIT APIs.
This commit also contains some simple utility classes (CtorDtorRunner2,
LocalCXXRuntimeOverrides2, JITTargetMachineBuilder) to support LLJIT and
LLLazyJIT.
Both of these classes are works in progress. Feedback from JIT clients is very
welcome!
llvm-svn: 335670
AsynchronousSymbolQuery::canStillFail checks the value of the callback to
prevent sending it redundant error notifications, so we need to reset it after
running it.
llvm-svn: 335664
CompileOnDemandLayer2 is a replacement for CompileOnDemandLayer built on the ORC
Core APIs. Functions in added modules are extracted and compiled lazily.
CompileOnDemandLayer2 supports multithreaded JIT'd code, and compilation on
multiple threads.
llvm-svn: 334967
materializing weak symbols as strong.
This removes some elaborate flag tweaking and plays nicer with RuntimeDyld,
which relies of weak/common flags to determine whether it should emit a given
weak definition. (Switching to strong up-front makes it appear as if there is
already an overriding definition, which would require an extra back-channel to
override).
llvm-svn: 334966
symbols in debug mode.
The MaterializationResponsibility class hijacks the Materializing flag to track
symbols that have not yet been resolved in order to guard against redundant
resolution. Since this is an API contract check and only enforced in debug mode
there is no reason to maintain the flag state in release mode.
llvm-svn: 334909
Add support for the "@high" and "@higha" symbol modifiers in powerpc64 assembly.
The modifiers represent accessing the segment consiting of bits 16-31 of a
64-bit address/offset.
Differential Revision: https://reviews.llvm.org/D47729
llvm-svn: 334855
Once a symbol has been selected for materialization it can no longer be
overridden. Stripping the weak flag guarantees this (override attempts will
then be treated as duplicate definitions and result in a DuplicateDefinition
error).
llvm-svn: 334771
If WaitUntilReady is set to true then blockingLookup will return once all
requested symbols are ready. If WaitUntilReady is set to false then
blockingLookup will return as soon as all requested symbols have been
resolved. In the latter case, if any error occurs in finalizing the symbols it
will be reported to the ExecutionSession, rather than returned by
blockingLookup.
llvm-svn: 334722
If a VSO has a fallback definition generator attached it will be called during
lookup (and lookupFlags) for any unresolved symbols. The definition generator
can add new definitions to the VSO for any unresolved symbol. This allows VSOs
to generate new definitions on demand.
The immediate use case for this code is supporting VSOs that can import
definitions found via dlsym on demand.
llvm-svn: 334538
Resolvers are required to find results for all requested symbols or return an
error, but if a resolver fails to adhere to this contract (by returning results
for only a subset of the requested symbols) then this code will infinite loop.
This assertion catches resolvers that fail to adhere to the contract.
llvm-svn: 334536
This only affects modules with lazy GVMaterializers attached (usually modules
read off disk using the lazy bitcode reader). For such modules, materializing
before compiling prevents crashes due to missing function bodies /
initializers.
llvm-svn: 334535
pre-existing SymbolFlags and SymbolToDefinition maps.
This constructor is useful when delegating work from an existing
IRMaterialiaztionUnit to a new one, as it avoids the cost of re-computing these
maps.
llvm-svn: 333852
This method returns the set of symbols in the target VSO that have queries
waiting on them. This can be used to make decisions about which symbols to
delegate to another MaterializationUnit (typically this will involve
delegating all symbols that have *not* been requested to another
MaterializationUnit so that materialization of those symbols can be
deferred until they are requested).
llvm-svn: 333684
and make it protected rather than private.
The new name reflects the actual information in the map, and this information
can be useful to derived classes (for example, to quickly look up the IR
definition of a requested symbol).
llvm-svn: 333683
The relocation for branch instructions in the dynamic loader of ExecutionEngine assumes branch instructions with R_PPC64_REL24 relocation type are only bl. However, with the tail call optimization, b instructions can be also used to jump into another function.
This patch makes the relocation to keep bits in the branch instruction other than the jump offset to avoid relocation rewrites a b instruction into bl.
Differential Revision: https://reviews.llvm.org/D47456
llvm-svn: 333502
