[llvm-branch-commits] [llvm] [BOLT] Add binary introspection/JIT manager (PR #81346)

[Rafael Auler via llvm-branch-commits]

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@@ -0,0 +1,99 @@
+#include "bolt/Rewrite/JITRewriteInstance.h"
+#include "bolt/Core/BinaryContext.h"
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/Support/TargetSelect.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace llvm::object;
+using namespace llvm::ELF;
+using namespace bolt;
+
+namespace {
+struct JITRewriteInstanceTester
+    : public testing::TestWithParam<Triple::ArchType> {
+  void SetUp() override {
+    initalizeLLVM();
+    initializeBOLT();
+  }
+
+protected:
+  void initalizeLLVM() {
+    llvm::InitializeAllTargetInfos();
+    llvm::InitializeAllTargetMCs();
+    llvm::InitializeAllAsmParsers();
+    llvm::InitializeAllDisassemblers();
+    llvm::InitializeAllTargets();
+    llvm::InitializeAllAsmPrinters();
+  }
+
+  void initializeBOLT() {
+    BOLTJIT = cantFail(bolt::JITRewriteInstance::createJITRewriteInstance(
+        {llvm::outs(), llvm::errs()}, /*IsPIC*/ false));
+    ASSERT_FALSE(!BOLTJIT);
+  }
+
+  std::unique_ptr<JITRewriteInstance> BOLTJIT;
+};
+} // namespace
+
+#ifdef X86_AVAILABLE
+
+// clang-format off
+extern "C" __attribute((naked)) int fib(int n)
+{
+  __asm__ __volatile__(
+    "pushq   %%r14\n"
+    "pushq   %%rbx\n"
+    "pushq   %%rax\n"
+    "movl    %%edi, %%r14d\n"
+    "xorl    %%ebx, %%ebx\n"
+    "cmpl    $0x2, %%edi\n"
+    "jge     .Ltmp0\n"
+    "movl    %%r14d, %%ecx\n"
+    "jmp     .Ltmp1\n"
+    ".Ltmp0:\n"
+    "xorl    %%ebx, %%ebx\n"
+    "nopw    %%cs:(%%rax,%%rax)\n"
+    ".Ltmp2:\n"
+    "leal    -0x1(%%r14), %%edi\n"
+    "callq   fib\n"
+    "leal    -0x2(%%r14), %%ecx\n"
+    "addl    %%eax, %%ebx\n"
+    "cmpl    $0x3, %%r14d\n"
+    "movl    %%ecx, %%r14d\n"
+    "ja      .Ltmp2\n"
+    ".Ltmp1:\n"
+    "addl    %%ecx, %%ebx\n"
+    "movl    %%ebx, %%eax\n"
+    "addq    $0x8, %%rsp\n"
+    "popq    %%rbx\n"
+    "popq    %%r14\n"
+    "retq\n"
+    :::);
+}
+// clang-format on
+
+INSTANTIATE_TEST_SUITE_P(X86, JITRewriteInstanceTester,
+                         ::testing::Values(Triple::x86_64));
+
+TEST_P(JITRewriteInstanceTester, DisassembleFib) {
+  EXPECT_EQ(fib(7), 13);
+
+  // BOLT JIT test/example
+  // Analyze fib function in this binary
+  // Disassemble 63 bytes
+  uint64_t Address = reinterpret_cast<uint64_t>(&fib);
+  StringRef Data = StringRef(reinterpret_cast<const char *>(&fib), 63);
----------------
rafaelauler wrote:

The rewriter object will only get knowledge about the symbol size after a call to to registerJITFunction. Not sure if I answered the question, but does it make sense to you? The user calling registerJITSection function will first make a section visible to the Rewriter, and then the user can partition this section in different functions using registerJITFunction, so the user passes the size down to the rewriter instead of the opposite.

https://github.com/llvm/llvm-project/pull/81346