On Sat, Nov 26, 2016 at 07:03:44AM +0000, Wang Nan wrote:
> PerfModule::doJIT JIT compile perfhook functions and saves result into
> a map. Add a test case for it.
>
> At this stage perfhook functions can do no useful things because they
> can't invoke external functions and can't return value. Following
> commits are going to make improvment.
>
> Don't hook functions right after jitted because bpf_object is unavailable
> during jitting but it should be the context of jitted functions.
>
> Signed-off-by: Wang Nan <wangn...@huawei.com>
...
> + for (Function *F : JITFunctions) {
> + JITSymbol sym = CompileLayer.findSymbol(F->getName().str(),
> true);
> +
> + /*
> + * Type of F->getSection() is moving from
> + * const char * to StringRef.
> + * Convert it to std::string so we don't need
> + * consider this API change.
> + */
> + std::string sec(F->getSection());
> + std::string hook(&sec.c_str()[sizeof("perfhook:") - 1]);
> + perf_hook_func_t func =
> (perf_hook_func_t)(intptr_t)sym.getAddress();
> +
> + if (JITResult[hook])
> + llvm::errs() << "Warning: multiple functions on hook "
> + << hook << ", only one is used\n";
> + JITResult[hook] = func;
> + }
> + return 0;
> +}
> +
> class ClangOptions {
> llvm::SmallString<PATH_MAX> FileName;
> llvm::SmallString<64> KVerDef;
> @@ -292,6 +359,10 @@ void perf_clang__init(void)
> LLVMInitializeBPFTarget();
> LLVMInitializeBPFTargetMC();
> LLVMInitializeBPFAsmPrinter();
> +
> + llvm::InitializeNativeTarget();
> + llvm::InitializeNativeTargetAsmPrinter();
> + llvm::InitializeNativeTargetAsmParser();
Looks great. I bet a lot of people reading perf code
won't be able to understand what you're doing here.
Could you please add a design doc on how perf<->clang/llvm interaction
is done.
Acked-by: Alexei Starovoitov <a...@kernel.org>
