From 439389ae19108f2ecb11c93a2f31a58768c18a8c Mon Sep 17 00:00:00 2001
From: Krystian Chmielewski <krystian.chmielewski@intel.com>
Date: Mon, 7 Mar 2022 12:50:37 +0000
Subject: [PATCH] Do not resolve external functions when none passed

This commit adds check in Linker::resolveExternalFunctions checking
if external functions are present before trying to resolve dependencies
and adds default values for ExternalFunctionInfo.

Signed-off-by: Krystian Chmielewski <krystian.chmielewski@intel.com>
---
 .../compiler_interface/external_functions.h   |  8 ++++----
 shared/source/compiler_interface/linker.cpp   |  4 ++++
 .../compiler_interface/linker_tests.cpp       | 20 ++++++++++++++++++-
 3 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/shared/source/compiler_interface/external_functions.h b/shared/source/compiler_interface/external_functions.h
index 74c717c37b..78d5f19243 100644
--- a/shared/source/compiler_interface/external_functions.h
+++ b/shared/source/compiler_interface/external_functions.h
@@ -22,10 +22,10 @@ enum ExternalFunctionResolveError : uint32_t {
 };
 
 struct ExternalFunctionInfo {
-    std::string functionName;
-    uint8_t barrierCount;
-    uint16_t numGrfRequired;
-    uint8_t simdSize;
+    std::string functionName = "";
+    uint8_t barrierCount = 0U;
+    uint16_t numGrfRequired = 0U;
+    uint8_t simdSize = 0U;
 };
 
 struct ExternalFunctionUsageKernel {
diff --git a/shared/source/compiler_interface/linker.cpp b/shared/source/compiler_interface/linker.cpp
index 63e03cb8bb..1a4d997164 100644
--- a/shared/source/compiler_interface/linker.cpp
+++ b/shared/source/compiler_interface/linker.cpp
@@ -504,6 +504,10 @@ void Linker::applyDebugDataRelocations(const NEO::Elf::Elf<NEO::Elf::EI_CLASS_64
 }
 
 bool Linker::resolveExternalFunctions(const KernelDescriptorsT &kernelDescriptors, std::vector<ExternalFunctionInfo> &externalFunctions) {
+    if (externalFunctions.size() == 0U) {
+        return true;
+    }
+
     ExternalFunctionInfosT externalFunctionsPtrs;
     FunctionDependenciesT functionDependenciesPtrs;
     KernelDependenciesT kernelDependenciesPtrs;
diff --git a/shared/test/unit_test/compiler_interface/linker_tests.cpp b/shared/test/unit_test/compiler_interface/linker_tests.cpp
index 25f996418c..8f0a2808e5 100644
--- a/shared/test/unit_test/compiler_interface/linker_tests.cpp
+++ b/shared/test/unit_test/compiler_interface/linker_tests.cpp
@@ -2357,10 +2357,28 @@ TEST(LinkerTests, givenDependencyOnMissingExternalFunctionWhenLinkingThenFail) {
     NEO::Linker::PatchableSegments patchableInstructionSegments;
     NEO::Linker::UnresolvedExternals unresolvedExternals;
     NEO::Linker::KernelDescriptorsT kernelDescriptors;
-    NEO::Linker::ExternalFunctionsT externalFunctions;
+    NEO::Linker::ExternalFunctionsT externalFunctions = {{"fun1", 0U, 128U, 8U}};
     auto linkResult = linker.link(
         globalVar, globalConst, exportedFunc, {},
         patchableGlobalVarSeg, patchableConstVarSeg, patchableInstructionSegments,
         unresolvedExternals, nullptr, nullptr, nullptr, kernelDescriptors, externalFunctions);
     EXPECT_EQ(LinkingStatus::Error, linkResult);
 }
+
+TEST(LinkerTests, givenDependencyOnMissingExternalFunctionAndNoExternalFunctionInfosWhenLinkingThenDoNotResolveDependenciesAndReturnSuccess) {
+    WhiteBox<NEO::LinkerInput> linkerInput;
+    linkerInput.extFunDependencies.push_back({"fun0", "fun1"});
+    NEO::Linker linker(linkerInput);
+    NEO::Linker::SegmentInfo globalVar, globalConst, exportedFunc;
+    NEO::GraphicsAllocation *patchableGlobalVarSeg = nullptr;
+    NEO::GraphicsAllocation *patchableConstVarSeg = nullptr;
+    NEO::Linker::PatchableSegments patchableInstructionSegments;
+    NEO::Linker::UnresolvedExternals unresolvedExternals;
+    NEO::Linker::KernelDescriptorsT kernelDescriptors;
+    NEO::Linker::ExternalFunctionsT externalFunctions;
+    auto linkResult = linker.link(
+        globalVar, globalConst, exportedFunc, {},
+        patchableGlobalVarSeg, patchableConstVarSeg, patchableInstructionSegments,
+        unresolvedExternals, nullptr, nullptr, nullptr, kernelDescriptors, externalFunctions);
+    EXPECT_EQ(LinkingStatus::LinkedFully, linkResult);
+}