From 6099e6ce9ac499719f4360d34a4c8841d01c02e7 Mon Sep 17 00:00:00 2001
From: Jason Ekstrand <jason.ekstrand@collabora.com>
Date: Wed, 13 Apr 2022 16:16:30 -0500
Subject: [PATCH] clc: Rework logging a bit

First, separate out the LLVM context logging to make it take a
clc_logger instead of passing in a string stream.  Currently, the LLVM
context may outlive the string stream which we assign which may lead to
use-after-free errors.  Second, use a separate string stream for clang
diagnosticl logging which we intentionally declare before the compiler
so the compiler can't outlive it.

Reviewed-by: Jesse Natalie <jenatali@microsoft.com>
Reviewed-by: Icecream95 <ixn@disroot.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15937>
---
 src/compiler/clc/clc_helpers.cpp | 35 +++++++++++++++++++++-----------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/src/compiler/clc/clc_helpers.cpp b/src/compiler/clc/clc_helpers.cpp
index 1a7f0c19f6a..7e4ae62b440 100644
--- a/src/compiler/clc/clc_helpers.cpp
+++ b/src/compiler/clc/clc_helpers.cpp
@@ -73,9 +73,14 @@ using ::llvm::raw_string_ostream;
 
 static void
 llvm_log_handler(const ::llvm::DiagnosticInfo &di, void *data) {
-   raw_string_ostream os { *reinterpret_cast<std::string *>(data) };
+   const clc_logger *logger = static_cast<clc_logger *>(data);
+
+   std::string log;
+   raw_string_ostream os { log };
    ::llvm::DiagnosticPrinterRawOStream printer { os };
    di.print(printer);
+
+   clc_error(logger, "%s", log.c_str());
 }
 
 class SPIRVKernelArg {
@@ -748,15 +753,21 @@ clc_compile_to_llvm_module(const struct clc_compile_args *args,
 {
    clc_initialize_llvm();
 
-   std::string log;
    std::unique_ptr<LLVMContext> llvm_ctx { new LLVMContext };
-   llvm_ctx->setDiagnosticHandlerCallBack(llvm_log_handler, &log);
+   llvm_ctx->setDiagnosticHandlerCallBack(llvm_log_handler,
+                                          const_cast<clc_logger *>(logger));
+
+   std::string diag_log_str;
+   raw_string_ostream diag_log_stream { diag_log_str };
 
    std::unique_ptr<clang::CompilerInstance> c { new clang::CompilerInstance };
-   clang::DiagnosticsEngine diag { new clang::DiagnosticIDs,
-         new clang::DiagnosticOptions,
-         new clang::TextDiagnosticPrinter(*new raw_string_ostream(log),
-                                          &c->getDiagnosticOpts(), true)};
+
+   clang::DiagnosticsEngine diag {
+      new clang::DiagnosticIDs,
+      new clang::DiagnosticOptions,
+      new clang::TextDiagnosticPrinter(diag_log_stream,
+                                       &c->getDiagnosticOpts())
+   };
 
    std::vector<const char *> clang_opts = {
       args->source.name,
@@ -786,13 +797,13 @@ clc_compile_to_llvm_module(const struct clc_compile_args *args,
                                                   clang_opts.data() + clang_opts.size(),
 #endif
                                                   diag)) {
-      clc_error(logger, "%sCouldn't create Clang invocation.\n", log.c_str());
+      clc_error(logger, "Couldn't create Clang invocation.\n");
       return {};
    }
 
    if (diag.hasErrorOccurred()) {
       clc_error(logger, "%sErrors occurred during Clang invocation.\n",
-                log.c_str());
+                diag_log_str.c_str());
       return {};
    }
 
@@ -802,8 +813,8 @@ clc_compile_to_llvm_module(const struct clc_compile_args *args,
    c->getDiagnosticOpts().ShowCarets = false;
 
    c->createDiagnostics(new clang::TextDiagnosticPrinter(
-                           *new raw_string_ostream(log),
-                           &c->getDiagnosticOpts(), true));
+                           diag_log_stream,
+                           &c->getDiagnosticOpts()));
 
    c->setTarget(clang::TargetInfo::CreateTargetInfo(
                    c->getDiagnostics(), c->getInvocation().TargetOpts));
@@ -870,7 +881,7 @@ clc_compile_to_llvm_module(const struct clc_compile_args *args,
    clang::EmitLLVMOnlyAction act(llvm_ctx.get());
    if (!c->ExecuteAction(act)) {
       clc_error(logger, "%sError executing LLVM compilation action.\n",
-                log.c_str());
+                diag_log_str.c_str());
       return {};
    }