[llvm] [llvm-exegesis] Add in snippet address annotation (PR #74218)
Aiden Grossman via llvm-commits
llvm-commits at lists.llvm.org
Sat Dec 2 18:05:57 PST 2023
https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/74218
This patch adds in a LLVM-EXEGESIS-SNIPPET-ADDRESS annotation that can be used in snippets executed by llvm-exegesis. This moves over the code that exegesis runs (including the setup) to start at the address specified. This allows for the execution of snippets that perform actions like RIP-relative variable referencing.
>From c9cd49b76066da6dee7d98e8fceccdd4f018886e Mon Sep 17 00:00:00 2001
From: Aiden Grossman <agrossman154 at yahoo.com>
Date: Sat, 2 Dec 2023 17:59:02 -0800
Subject: [PATCH] [llvm-exegesis] Add in snippet address annotation
This patch adds in a LLVM-EXEGESIS-SNIPPET-ADDRESS annotation that can
be used in snippets executed by llvm-exegesis. This moves over the code
that exegesis runs (including the setup) to start at the address
specified. This allows for the execution of snippets that perform
actions like RIP-relative variable referencing.
---
.../latency/memory-annotations-unsupported.s | 2 +-
.../snippet-address-annotations-unsupported.s | 9 +++++++
.../latency/subprocess-address-annotation.s | 26 +++++++++++++++++++
.../tools/llvm-exegesis/lib/BenchmarkResult.h | 3 +++
.../llvm-exegesis/lib/BenchmarkRunner.cpp | 12 +++++++--
llvm/tools/llvm-exegesis/lib/SnippetFile.cpp | 6 +++++
llvm/tools/llvm-exegesis/llvm-exegesis.cpp | 6 +++--
.../llvm-exegesis/X86/SnippetFileTest.cpp | 10 +++++++
8 files changed, 69 insertions(+), 5 deletions(-)
create mode 100644 llvm/test/tools/llvm-exegesis/X86/latency/snippet-address-annotations-unsupported.s
create mode 100644 llvm/test/tools/llvm-exegesis/X86/latency/subprocess-address-annotation.s
diff --git a/llvm/test/tools/llvm-exegesis/X86/latency/memory-annotations-unsupported.s b/llvm/test/tools/llvm-exegesis/X86/latency/memory-annotations-unsupported.s
index 5d06a0ceff5c7..c483d28adf0e1 100644
--- a/llvm/test/tools/llvm-exegesis/X86/latency/memory-annotations-unsupported.s
+++ b/llvm/test/tools/llvm-exegesis/X86/latency/memory-annotations-unsupported.s
@@ -2,7 +2,7 @@
# RUN: not llvm-exegesis -mtriple=x86_64-unknown-unknown -snippets-file=%s -mode=latency 2>&1 | FileCheck %s
-# CHECK: llvm-exegesis error: Memory annotations are only supported in subprocess execution mode
+# CHECK: llvm-exegesis error: Memory and snippet address annotations are only supported in subprocess execution mode
# LLVM-EXEGESIS-MEM-DEF test1 4096 ff
diff --git a/llvm/test/tools/llvm-exegesis/X86/latency/snippet-address-annotations-unsupported.s b/llvm/test/tools/llvm-exegesis/X86/latency/snippet-address-annotations-unsupported.s
new file mode 100644
index 0000000000000..c38c41d2aed9b
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/X86/latency/snippet-address-annotations-unsupported.s
@@ -0,0 +1,9 @@
+# REQUIRES: exegesis-can-measure-latency, x86_64-linux
+
+# RUN: not llvm-exegesis -mtriple=x86_64-unknown-unknown -snippets-file=%s -mode=latency 2>&1 | FileCheck %s
+
+# CHECK: llvm-exegesis error: Memory and snippet address annotations are only supported in subprocess execution mode
+
+# LLVM-EXEGESIS-SNIPPET-ADDRESS 10000
+
+movq $0, %rax
diff --git a/llvm/test/tools/llvm-exegesis/X86/latency/subprocess-address-annotation.s b/llvm/test/tools/llvm-exegesis/X86/latency/subprocess-address-annotation.s
new file mode 100644
index 0000000000000..1b104b30bb288
--- /dev/null
+++ b/llvm/test/tools/llvm-exegesis/X86/latency/subprocess-address-annotation.s
@@ -0,0 +1,26 @@
+# REQUIRES: exegesis-can-measure-latency, x86_64-linux
+
+# RUN: llvm-exegesis -mtriple=x86_64-unknown-unknown -mode=latency -snippets-file=%s -execution-mode=subprocess | FileCheck %s
+
+# Check that the code is loaded in at the expected address.
+
+# LLVM-EXEGESIS-SNIPPET-ADDRESS 20000
+# LLVM-EXEGESIS-DEFREG RAX 0
+# LLVM-EXEGESIS-DEFREG R14 127
+# LLVM-EXEGESIS-DEFREG R15 0
+# LLVM-EXEGESIS-DEFREG RDI 0
+
+# Load the instruction pointer and round down to the nearest page as there
+# will be some setup code loaded in before this part begins to execute.
+lea 0(%rip), %rax
+shrq $12, %rax
+shlq $12, %rax
+
+cmpq $0x20000, %rax
+cmovneq %r14, %r15
+
+movq $60, %rax
+movq %r15, %rdi
+syscall
+
+# CHECK-NOT: error: 'Child benchmarking process exited with non-zero exit code: Child process returned with unknown exit code'
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
index 38111519a2c89..0d08febae20cb 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkResult.h
@@ -70,6 +70,9 @@ struct BenchmarkKey {
// An opaque configuration, that can be used to separate several benchmarks of
// the same instruction under different configurations.
std::string Config;
+ // The address that the snippet should be loaded in at if the execution mode
+ // being used supports it.
+ intptr_t SnippetAddress = 0;
};
struct BenchmarkMeasure {
diff --git a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
index 85375dec2a44c..700f9beb962ec 100644
--- a/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
+++ b/llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp
@@ -404,9 +404,17 @@ class SubProcessFunctionExecutorImpl
#endif // GLIBC_INITS_RSEQ
size_t FunctionDataCopySize = this->Function.FunctionBytes.size();
+ void *MapAddress = NULL;
+ int MapFlags = MAP_PRIVATE | MAP_ANONYMOUS;
+
+ if (Key.SnippetAddress != 0) {
+ MapAddress = reinterpret_cast<void *>(Key.SnippetAddress);
+ MapFlags |= MAP_FIXED_NOREPLACE;
+ }
+
char *FunctionDataCopy =
- (char *)mmap(NULL, FunctionDataCopySize, PROT_READ | PROT_WRITE,
- MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
+ (char *)mmap(MapAddress, FunctionDataCopySize, PROT_READ | PROT_WRITE,
+ MapFlags, 0, 0);
if ((intptr_t)FunctionDataCopy == -1)
exit(ChildProcessExitCodeE::FunctionDataMappingFailed);
diff --git a/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp b/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp
index d85a9f190655a..a140f7b2ba77b 100644
--- a/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp
+++ b/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp
@@ -131,6 +131,12 @@ class BenchmarkCodeStreamer : public MCStreamer, public AsmCommentConsumer {
Result->Key.MemoryMappings.push_back(std::move(MemMap));
return;
}
+ if (CommentText.consume_front("SNIPPET-ADDRESS")) {
+ // LLVM-EXEGESIS-SNIPPET-ADDRESS <address>
+ Result->Key.SnippetAddress =
+ std::stol(CommentText.trim().str(), nullptr, 16);
+ return;
+ }
}
unsigned numInvalidComments() const { return InvalidComments; }
diff --git a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
index 261335a817d06..66bc94271756c 100644
--- a/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
+++ b/llvm/tools/llvm-exegesis/llvm-exegesis.cpp
@@ -533,8 +533,10 @@ void benchmarkMain() {
for (const auto &Configuration : Configurations) {
if (ExecutionMode != BenchmarkRunner::ExecutionModeE::SubProcess &&
(Configuration.Key.MemoryMappings.size() != 0 ||
- Configuration.Key.MemoryValues.size() != 0))
- ExitWithError("Memory annotations are only supported in subprocess "
+ Configuration.Key.MemoryValues.size() != 0 ||
+ Configuration.Key.SnippetAddress != 0))
+ ExitWithError("Memory and snippet address annotations are only "
+ "supported in subprocess "
"execution mode");
}
}
diff --git a/llvm/unittests/tools/llvm-exegesis/X86/SnippetFileTest.cpp b/llvm/unittests/tools/llvm-exegesis/X86/SnippetFileTest.cpp
index 2bab3aa15baad..52eb211c37272 100644
--- a/llvm/unittests/tools/llvm-exegesis/X86/SnippetFileTest.cpp
+++ b/llvm/unittests/tools/llvm-exegesis/X86/SnippetFileTest.cpp
@@ -209,6 +209,16 @@ TEST_F(X86SnippetFileTest, MemoryMappingNoDefinition) {
consumeError(std::move(Error));
}
+TEST_F(X86SnippetFileTest, SnippetAddress) {
+ auto Snippets = TestCommon(R"(
+ # LLVM-EXEGESIS-SNIPPET-ADDRESS 0x10000
+ )");
+ ASSERT_TRUE(static_cast<bool>(Snippets));
+ EXPECT_THAT(*Snippets, SizeIs(1));
+ const auto &Snippet = (*Snippets)[0];
+ EXPECT_EQ(Snippet.Key.SnippetAddress, 0x10000);
+}
+
} // namespace
} // namespace exegesis
} // namespace llvm
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