[llvm] 27f37db - [llvm-exegesis] Use MCJIT only for execution
Pavel Kosov via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 16 00:39:31 PDT 2023
Author: Pavel Kosov
Date: 2023-06-16T10:38:52+03:00
New Revision: 27f37db76a79e746561ad2545ff6ccf0d50cc38c
URL: https://github.com/llvm/llvm-project/commit/27f37db76a79e746561ad2545ff6ccf0d50cc38c
DIFF: https://github.com/llvm/llvm-project/commit/27f37db76a79e746561ad2545ff6ccf0d50cc38c.diff
LOG: [llvm-exegesis] Use MCJIT only for execution
Initially, llvm-exegesis was generating the benchmark code for the
host CPU to execute it inside its own process. Thus, MCJIT was reused
for fetching function's bytes to fill the assembled_snippet field in
the benchmark report.
Later, the --mtriple and --benchmark-phase command line options were
introduced that are handy for testing snippet generation even if
snippet execution is not possible. In that setup, MCJIT is asked to
parse an object file for a foreign CPU or operating system that is
probably not guaranteed to succeed and was actually observed to fail
in https://reviews.llvm.org/D145763.
This commit implements a much simplified function's code fetching,
assuming the benchmark function is the only function in the object file
and it spans across the entire text section (note that MCJIT-based code
has more or less the same assumption - see TrackingSectionMemoryManager
class).
~~~
Huawei RRI, OS Lab
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D148921
Added:
llvm/test/tools/llvm-exegesis/AArch64/print-assembled-snippet.s
llvm/test/tools/llvm-exegesis/Mips/print-assembled-snippet.s
llvm/test/tools/llvm-exegesis/PowerPC/print-assembled-snippet.s
llvm/test/tools/llvm-exegesis/X86/print-assembled-snippet.s
Modified:
llvm/tools/llvm-exegesis/lib/Assembler.cpp
llvm/tools/llvm-exegesis/lib/Assembler.h
llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
Removed:
################################################################################
diff --git a/llvm/test/tools/llvm-exegesis/AArch64/print-assembled-snippet.s b/llvm/test/tools/llvm-exegesis/AArch64/print-assembled-snippet.s
new file mode 100644
index 0000000000000..e8b312d7a6ae9
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/AArch64/print-assembled-snippet.s
@@ -0,0 +1,31 @@
+# Check that "assembled_snippet" is fetched correctly from object file.
+# Feel free to update the snippet in this test if the code generated by the
+# snippet repetitor was changed intentionally and it is still fetched correctly.
+
+# RUN: llvm-exegesis --mtriple=aarch64-linux-gnu --mcpu=generic --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-LINUX
+
+# RUN: llvm-exegesis --mtriple=aarch64-windows-gnu --mcpu=generic --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-WINDOWS-GNU
+
+# RUN: llvm-exegesis --mtriple=aarch64-windows-msvc --mcpu=generic --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-WINDOWS-MSVC
+
+# LLVM-EXEGESIS-DEFREG X0 0
+# LLVM-EXEGESIS-DEFREG X1 0
+add x0, x0, x1
+
+# CHECK-LINUX: cpu_name: generic
+# CHECK-LINUX: llvm_triple: aarch64-unknown-linux-gnu
+# CHECK-LINUX: assembled_snippet: 000080D2010080D20000018B0000018B0000018B0000018BC0035FD6{{$}}
+
+# CHECK-WINDOWS-GNU: cpu_name: generic
+# CHECK-WINDOWS-GNU: llvm_triple: aarch64-unknown-windows-gnu
+# CHECK-WINDOWS-GNU: assembled_snippet: 000080D2010080D20000018B0000018B0000018B0000018BC0035FD6{{$}}
+
+# CHECK-WINDOWS-MSVC: cpu_name: generic
+# CHECK-WINDOWS-MSVC: llvm_triple: aarch64-unknown-windows-msvc
+# CHECK-WINDOWS-MSVC: assembled_snippet: 000080D2010080D20000018B0000018B0000018B0000018BC0035FD6{{$}}
diff --git a/llvm/test/tools/llvm-exegesis/Mips/print-assembled-snippet.s b/llvm/test/tools/llvm-exegesis/Mips/print-assembled-snippet.s
new file mode 100644
index 0000000000000..f0844c4145a2b
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/Mips/print-assembled-snippet.s
@@ -0,0 +1,23 @@
+# Check that "assembled_snippet" is fetched correctly from object file.
+# Feel free to update the snippet in this test if the code generated by the
+# snippet repetitor was changed intentionally and it is still fetched correctly.
+
+# RUN: llvm-exegesis --mtriple=mips-linux-gnu --mcpu=generic --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-LINUX
+
+# RUN: llvm-exegesis --mtriple=mips64-linux-gnu --mcpu=generic --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-LINUX-64
+
+# LLVM-EXEGESIS-DEFREG A0 0
+# LLVM-EXEGESIS-DEFREG A1 0
+add $2, $5, $4
+
+# CHECK-LINUX: cpu_name: generic
+# CHECK-LINUX: llvm_triple: mips-unknown-linux-gnu
+# CHECK-LINUX: assembled_snippet: 340400003405000000A4102000A4102000A4102000A4102003E00008{{$}}
+
+# CHECK-LINUX-64: cpu_name: generic
+# CHECK-LINUX-64: llvm_triple: mips64-unknown-linux-gnu
+# CHECK-LINUX-64: assembled_snippet: 340400003405000000A4102000A4102000A4102000A4102003E00008{{$}}
diff --git a/llvm/test/tools/llvm-exegesis/PowerPC/print-assembled-snippet.s b/llvm/test/tools/llvm-exegesis/PowerPC/print-assembled-snippet.s
new file mode 100644
index 0000000000000..75cad37a768eb
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/PowerPC/print-assembled-snippet.s
@@ -0,0 +1,15 @@
+# Check that "assembled_snippet" is fetched correctly from object file.
+# Feel free to update the snippet in this test if the code generated by the
+# snippet repetitor was changed intentionally and it is still fetched correctly.
+
+# RUN: llvm-exegesis --mtriple=powerpc64le-linux-gnu --mcpu=pwr8 --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-LINUX-64-LE
+
+# LLVM-EXEGESIS-DEFREG R3 0
+# LLVM-EXEGESIS-DEFREG R4 0
+add 3, 4, 3
+
+# CHECK-LINUX-64-LE: cpu_name: pwr8
+# CHECK-LINUX-64-LE: llvm_triple: powerpc64le-unknown-linux-gnu
+# CHECK-LINUX-64-LE: assembled_snippet: 0000603800008038141A647C141A647C141A647C141A647C2000804E000000000000000000000000{{$}}
diff --git a/llvm/test/tools/llvm-exegesis/X86/print-assembled-snippet.s b/llvm/test/tools/llvm-exegesis/X86/print-assembled-snippet.s
new file mode 100644
index 0000000000000..532901d0e0430
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/X86/print-assembled-snippet.s
@@ -0,0 +1,32 @@
+# Check that "assembled_snippet" is fetched correctly from object file.
+# Feel free to update the snippet in this test if the code generated by the
+# snippet repetitor was changed intentionally and it is still fetched correctly.
+
+# RUN: llvm-exegesis --mtriple=x86_64-linux-gnu --mcpu=x86-64 --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-LINUX
+
+# RUN: llvm-exegesis --mtriple=x86_64-windows-gnu --mcpu=x86-64 --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-WINDOWS-GNU
+
+# RUN: llvm-exegesis --mtriple=x86_64-windows-msvc --mcpu=x86-64 --benchmark-phase=prepare-and-assemble-snippet \
+# RUN: --snippets-file=%s --mode=latency --repetition-mode=duplicate \
+# RUN: | FileCheck %s --check-prefix=CHECK-WINDOWS-MSVC
+
+# LLVM-EXEGESIS-DEFREG RDI 0
+# LLVM-EXEGESIS-DEFREG RSI 0
+# LLVM-EXEGESIS-DEFREG RAX 0
+leaq (%rdi,%rsi), %rax
+
+# CHECK-LINUX: cpu_name: x86-64
+# CHECK-LINUX: llvm_triple: x86_64-unknown-linux-gnu
+# CHECK-LINUX: assembled_snippet: 48BF000000000000000048BE000000000000000048B80000000000000000488D0437488D0437488D0437488D0437C3{{$}}
+
+# CHECK-WINDOWS-GNU: cpu_name: x86-64
+# CHECK-WINDOWS-GNU: llvm_triple: x86_64-unknown-windows-gnu
+# CHECK-WINDOWS-GNU: assembled_snippet: 565748BF000000000000000048BE000000000000000048B80000000000000000488D0437488D0437488D0437488D04375F5EC3{{$}}
+
+# CHECK-WINDOWS-MSVC: cpu_name: x86-64
+# CHECK-WINDOWS-MSVC: llvm_triple: x86_64-unknown-windows-msvc
+# CHECK-WINDOWS-MSVC: assembled_snippet: 565748BF000000000000000048BE000000000000000048B80000000000000000488D0437488D0437488D0437488D04375F5EC3{{$}}
diff --git a/llvm/tools/llvm-exegesis/lib/Assembler.cpp b/llvm/tools/llvm-exegesis/lib/Assembler.cpp
index 07465c71afc70..8e561f587cc2a 100644
--- a/llvm/tools/llvm-exegesis/lib/Assembler.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Assembler.cpp
@@ -27,6 +27,7 @@
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/Support/Alignment.h"
#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
namespace llvm {
namespace exegesis {
@@ -323,5 +324,38 @@ ExecutableFunction::ExecutableFunction(
StringRef(reinterpret_cast<const char *>(FunctionAddress), CodeSize);
}
+Error getBenchmarkFunctionBytes(const StringRef InputData,
+ std::vector<uint8_t> &Bytes) {
+ const auto Holder = getObjectFromBuffer(InputData);
+ const auto *Obj = Holder.getBinary();
+ // See RuntimeDyldImpl::loadObjectImpl(Obj) for much more complete
+ // implementation.
+
+ // Find the only function in the object file.
+ SmallVector<object::SymbolRef, 1> Functions;
+ for (auto &Sym : Obj->symbols()) {
+ auto SymType = Sym.getType();
+ if (SymType && *SymType == object::SymbolRef::Type::ST_Function)
+ Functions.push_back(Sym);
+ }
+ if (Functions.size() != 1)
+ return make_error<Failure>("Exactly one function expected");
+
+ // Find the containing section - it is assumed to contain only this function.
+ auto SectionOrErr = Functions.front().getSection();
+ if (!SectionOrErr || *SectionOrErr == Obj->section_end())
+ return make_error<Failure>("Section not found");
+
+ auto Address = Functions.front().getAddress();
+ if (!Address || *Address != SectionOrErr.get()->getAddress())
+ return make_error<Failure>("Unexpected layout");
+
+ auto ContentsOrErr = SectionOrErr.get()->getContents();
+ if (!ContentsOrErr)
+ return ContentsOrErr.takeError();
+ Bytes.assign(ContentsOrErr->begin(), ContentsOrErr->end());
+ return Error::success();
+}
+
} // namespace exegesis
} // namespace llvm
diff --git a/llvm/tools/llvm-exegesis/lib/Assembler.h b/llvm/tools/llvm-exegesis/lib/Assembler.h
index 2a83344b751e5..cd1e398e4a564 100644
--- a/llvm/tools/llvm-exegesis/lib/Assembler.h
+++ b/llvm/tools/llvm-exegesis/lib/Assembler.h
@@ -121,6 +121,10 @@ struct ExecutableFunction {
StringRef FunctionBytes;
};
+// Copies benchmark function's bytes from benchmark object.
+Error getBenchmarkFunctionBytes(const StringRef InputData,
+ std::vector<uint8_t> &Bytes);
+
// Creates a void(int8*) MachineFunction.
MachineFunction &createVoidVoidPtrMachineFunction(StringRef FunctionID,
Module *Module,
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index e1df2940a9b7e..f934b8ec4c6cc 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -174,10 +174,10 @@ BenchmarkRunner::getRunnableConfiguration(
LoopBodySizeForSnippet);
if (Error E = Snippet.takeError())
return std::move(E);
- const ExecutableFunction EF(State.createTargetMachine(),
- getObjectFromBuffer(*Snippet));
- const auto FnBytes = EF.getFunctionBytes();
- llvm::append_range(InstrBenchmark.AssembledSnippet, FnBytes);
+
+ if (auto Err = getBenchmarkFunctionBytes(*Snippet,
+ InstrBenchmark.AssembledSnippet))
+ return std::move(Err);
}
// Assemble NumRepetitions instructions repetitions of the snippet for
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