Native backtrace implementation

Better string handling in LLVM IR generator

Author: grendello

src/Xamarin.Android.Build.Tasks/Tasks/LinkApplicationSharedLibraries.cs

@@ -16,6 +16,8 @@ namespace Xamarin.Android.Tasks
 {
 	public class LinkApplicationSharedLibraries : AndroidAsyncTask
 	{
+		const int NDK_API_LEVEL = 21; // TODO: don't hardcode the API level
+
 		public override string TaskPrefix => "LAS";
 
 		sealed class Config
@@ -118,16 +120,38 @@ void RunLinker (Config config)
 		IEnumerable<Config> GetLinkerConfigs ()
 		{
 			NdkTools ndk = null;
+			string clangRuntimeDirTop = null;
+
 			if (EnableMarshalMethodTracing) {
 				ndk = NdkTools.Create (AndroidNdkDirectory, logErrors: false, log: Log);
+
+				// Doesn't matter for which arch we run the compiler, they all share the same topmost runtime dir
+				string clangPath = ndk.GetToolPath (NdkToolKind.CompilerCPlusPlus, AndroidTargetArch.Arm64, NDK_API_LEVEL);
+				int ret = MonoAndroidHelper.RunProcess (
+					clangPath, "-print-runtime-dir",
+					(object sender, DataReceivedEventArgs e) => { // stdout
+						if (clangRuntimeDirTop == null && !String.IsNullOrEmpty (e.Data)) {
+							clangRuntimeDirTop = e.Data;
+						}
+					},
+					(object sender, DataReceivedEventArgs e) => { // stderr
+						if (!String.IsNullOrEmpty (e.Data)) {
+							Log.LogError (e.Data);
+						}
+					}
+				);
+
+				if (ret != 0) {
+					Log.LogError ($"Failed to obtain clang runtime path from {clangPath}");
+				}
 			}
 
 			string runtimeNativeLibsDir = Path.GetFullPath (Path.Combine (AndroidBinUtilsDirectory, "..", "..", "..", "lib"));
 			var abis = new Dictionary <string, InputFiles> (StringComparer.Ordinal);
 			ITaskItem[] dsos = ApplicationSharedLibraries;
 			foreach (ITaskItem item in dsos) {
 				string abi = item.GetMetadata ("abi");
-				abis [abi] = GatherFilesForABI (item.ItemSpec, abi, ObjectFiles, runtimeNativeLibsDir, ndk);
+				abis [abi] = GatherFilesForABI (item.ItemSpec, abi, ObjectFiles, runtimeNativeLibsDir, ndk, clangRuntimeDirTop);
 			}
 
 			const string commonLinkerArgs =
@@ -205,7 +229,7 @@ IEnumerable<Config> GetLinkerConfigs ()
 			}
 		}
 
-		InputFiles GatherFilesForABI (string runtimeSharedLibrary, string abi, ITaskItem[] objectFiles, string runtimeNativeLibsDir, NdkTools ndk)
+		InputFiles GatherFilesForABI (string runtimeSharedLibrary, string abi, ITaskItem[] objectFiles, string runtimeNativeLibsDir, NdkTools ndk, string clangRuntimeDirTop)
 		{
 			List<string> extraLibraries = null;
 
@@ -214,11 +238,22 @@ InputFiles GatherFilesForABI (string runtimeSharedLibrary, string abi, ITaskItem
 					throw new ArgumentNullException (nameof (ndk));
 				}
 
-				string libPath = ndk.GetDirectoryPath (NdkToolchainDir.PlatformLib, MonoAndroidHelper.AbiToTargetArch (abi), 21); // TODO: don't hardcode the API level
+				AndroidTargetArch targetArch = MonoAndroidHelper.AbiToTargetArch (abi);
+				string clangRuntimeAbi = MonoAndroidHelper.ArchToClangRuntimeAbi (targetArch);
+				string clangLibraryAbi = MonoAndroidHelper.ArchToClangLibraryAbi (targetArch);
+				string unwindLibPath = Path.GetFullPath (Path.Combine (clangRuntimeDirTop, clangRuntimeAbi, "libunwind.a"));
+				string builtinsLibPath = Path.GetFullPath (Path.Combine (clangRuntimeDirTop, $"libclang_rt.builtins-{clangLibraryAbi}-android.a"));
+				string libPath = ndk.GetDirectoryPath (NdkToolchainDir.PlatformLib, targetArch, NDK_API_LEVEL);
+				string cxxAbiLibPath = Path.GetFullPath (Path.Combine (libPath, "..", "libc++abi.a"));
+
 				extraLibraries = new List<string> {
 					Path.Combine (runtimeNativeLibsDir, MonoAndroidHelper.AbiToRid (abi), "libmarshal-methods-tracing.a"),
 					$"-L \"{libPath}\"",
+					$"\"{builtinsLibPath}\"",
+					$"\"{cxxAbiLibPath}\"",
+					$"\"{unwindLibPath}\"",
 					"-lc",
+					"-ldl",
 					"-llog", // tracing uses android logger
 				};
 			}

src/Xamarin.Android.Build.Tasks/Utilities/LlvmIrGenerator/LlvmIrGenerator.Code.cs

@@ -418,6 +418,9 @@ public void EmitLabel (LlvmIrFunction function, string labelName)
 						} else {
 							throw new InvalidOperationException ($"Unexpected pointer type in argument {i}, '{argument.Type}'");
 						}
+					} else if (argument.Value is string str) {
+						StringSymbolInfo info = StringManager.Add (str);
+						WriteGetStringPointer (info.SymbolName, info.Size, indent: false, detectBitness: true, skipPointerType: true);
 					} else {
 						Output.Write (argument.Value.ToString ());
 					}

src/Xamarin.Android.Build.Tasks/Utilities/LlvmIrGenerator/LlvmIrGenerator.cs

@@ -52,18 +52,6 @@ public PackedStructureMember (StructureMemberInfo<T> memberInfo, object? value,
 			}
 		}
 
-		public sealed class StringSymbolInfo
-		{
-			public readonly string SymbolName;
-			public readonly ulong Size;
-
-			public StringSymbolInfo (string symbolName, ulong size)
-			{
-				SymbolName = symbolName;
-				Size = size;
-			}
-		}
-
 		static readonly Dictionary<Type, string> typeMap = new Dictionary<Type, string> {
 			{ typeof (bool), "i8" },
 			{ typeof (byte), "i8" },
@@ -165,11 +153,13 @@ public StringSymbolInfo (string symbolName, ulong size)
 		public AndroidTargetArch TargetArch { get; }
 
 		protected LlvmIrMetadataManager MetadataManager { get; }
+		protected LlvmIrStringManager StringManager { get; }
 
 		protected LlvmIrGenerator (AndroidTargetArch arch, TextWriter output, string fileName)
 		{
 			Output = output;
 			MetadataManager = new LlvmIrMetadataManager ();
+			StringManager = new LlvmIrStringManager ();
 			TargetArch = arch;
 			Is64Bit = arch == AndroidTargetArch.X86_64 || arch == AndroidTargetArch.Arm64;
 			this.fileName = fileName;
@@ -455,7 +445,7 @@ bool MaybeWriteStructureString<T> (StructureInfo<T> info, StructureMemberInfo<T>
 				return false;
 			}
 
-			StringSymbolInfo stringSymbol = WriteUniqueString ($"__{info.Name}_{smi.Info.Name}", str, ref structStringCounter);
+			StringSymbolInfo stringSymbol = StringManager.Add (str, groupName: info.Name, symbolSuffix: smi.Info.Name);//WriteUniqueString ($"__{info.Name}_{smi.Info.Name}", str, ref structStringCounter);
 			instance.AddPointerData (smi, stringSymbol.SymbolName, stringSymbol.Size);
 
 			return true;
@@ -622,12 +612,11 @@ public void WriteArray (IList<string> values, string symbolName, string? initial
 			WriteEOL ();
 			WriteEOL (initialComment ?? symbolName);
 
-			ulong arrayStringCounter = 0;
-			var strings = new List<StringSymbolInfo> ();
+						var strings = new List<StringSymbolInfo> ();
 
 			foreach (string s in values) {
-				StringSymbolInfo symbol = WriteUniqueString ($"__{symbolName}", s, ref arrayStringCounter, LlvmIrVariableOptions.LocalConstexprString);
-				strings.Add (new StringSymbolInfo (symbol.SymbolName, symbol.Size));
+				StringSymbolInfo symbol = StringManager.Add (s, groupName: symbolName);
+				strings.Add (symbol);
 			}
 
 			if (strings.Count > 0) {
@@ -1137,12 +1126,12 @@ void WriteBufferToOutput (TextWriter? writer)
 			}
 		}
 
-		void WriteGetStringPointer (string? variableName, ulong size, bool indent = true, TextWriter? output = null)
+		void WriteGetStringPointer (string? variableName, ulong size, bool indent = true, TextWriter? output = null, bool detectBitness = false, bool skipPointerType = false)
 		{
-			WriteGetBufferPointer (variableName, "i8*", size, indent, output);
+			WriteGetBufferPointer (variableName, "i8*", size, indent, output, detectBitness, skipPointerType);
 		}
 
-		void WriteGetBufferPointer (string? variableName, string irType, ulong size, bool indent = true, TextWriter? output = null)
+		void WriteGetBufferPointer (string? variableName, string irType, ulong size, bool indent = true, TextWriter? output = null, bool detectBitness = false, bool skipPointerType = false)
 		{
 			output = EnsureOutput (output);
 			if (indent) {
@@ -1160,8 +1149,12 @@ void WriteGetBufferPointer (string? variableName, string irType, ulong size, boo
 					irBaseType = irType;
 				}
 
+				string indexType = detectBitness && Is64Bit ? "i64" : "i32";
 				// $"{irType} getelementptr inbounds ([{size} x {irBaseType}], [{size} x {irBaseType}]* @{variableName}, i32 0, i32 0)"
-				output.Write (irType);
+				if (!skipPointerType) {
+					output.Write (irType);
+				}
+
 				output.Write (" getelementptr inbounds ([");
 				output.Write (size);
 				output.Write (" x ");
@@ -1172,7 +1165,11 @@ void WriteGetBufferPointer (string? variableName, string irType, ulong size, boo
 				output.Write (irBaseType);
 				output.Write ("]* @");
 				output.Write (variableName);
-				output.Write (", i32 0, i32 0)");
+				output.Write (", ");
+				output.Write (indexType);
+				output.Write (" 0, ");
+				output.Write (indexType);
+				output.Write (" 0)");
 			}
 		}
 
@@ -1186,7 +1183,6 @@ public void WriteNameValueArray (string symbolName, IDictionary<string, string>
 
 			var strings = new List<StringSymbolInfo> ();
 			long i = 0;
-			ulong arrayStringCounter = 0;
 
 			foreach (var kvp in arrayContents) {
 				string name = kvp.Key;
@@ -1205,8 +1201,8 @@ public void WriteNameValueArray (string symbolName, IDictionary<string, string>
 
 			void WriteArrayString (string str, string symbolSuffix)
 			{
-				StringSymbolInfo symbol = WriteUniqueString ($"__{symbolName}_{symbolSuffix}", str, ref arrayStringCounter, LlvmIrVariableOptions.LocalConstexprString);
-				strings.Add (new StringSymbolInfo (symbol.SymbolName, symbol.Size));
+				StringSymbolInfo symbol = StringManager.Add (str, groupName: symbolName, symbolSuffix: symbolSuffix);
+				strings.Add (symbol);
 			}
 		}
 
@@ -1279,28 +1275,6 @@ public void WriteVariable<T> (string symbolName, T value, LlvmIrVariableOptions
 			Output.WriteLine (size);
 		}
 
-		/// <summary>
-		/// Writes a private string. Strings without symbol names aren't exported, but they may be referenced by other
-		/// symbols
-		/// </summary>
-		public string WriteString (string value)
-		{
-			return WriteString (value, LlvmIrVariableOptions.LocalString);
-		}
-
-		/// <summary>
-		/// Writes a string with automatically generated symbol name and symbol options (writeability, visibility etc) specified in the <paramref name="options"/> parameter.
-		/// </summary>
-		public string WriteString (string value, LlvmIrVariableOptions options)
-		{
-			string name = $"@.str";
-			if (stringCounter > 0) {
-				name += $".{stringCounter}";
-			}
-			stringCounter++;
-			return WriteString (name, value, options);
-		}
-
 		/// <summary>
 		/// Writes a global, C++ constexpr style string
 		/// </summary>
@@ -1317,101 +1291,27 @@ public string WriteString (string symbolName, string value, LlvmIrVariableOption
 			return WriteString (symbolName, value, options, out _);
 		}
 
-		/// <summary>
-		/// Writes a local, constexpr style string and returns its size in <paramref name="stringSize"/>
-		/// </summary>
-		public string WriteString (string symbolName, string value, out ulong stringSize)
-		{
-			return WriteString (symbolName, value, LlvmIrVariableOptions.LocalConstexprString, out stringSize);
-		}
-
 		/// <summary>
 		/// Writes a string with specified <paramref name="symbolName"/>, and symbol options (writeability, visibility etc) specified in the <paramref name="options"/>
 		/// parameter.  Returns string size (in bytes) in <paramref name="stringSize"/>
 		/// </summary>
 		public string WriteString (string symbolName, string value, LlvmIrVariableOptions options, out ulong stringSize)
 		{
-			string strSymbolName;
-			bool global = options.IsGlobal;
-			if (global) {
-				strSymbolName = $"__{symbolName}";
-			} else {
-				strSymbolName = symbolName;
-			}
-
-			string quotedString = QuoteString (value, out stringSize);
-
-			// It might seem counter-intuitive that when we're requested to write a global string, here we generate a **local** one,
-			// but global strings are actually pointers to local storage.
-			WriteGlobalSymbolStart (strSymbolName, global ? LlvmIrVariableOptions.LocalConstexprString : options);
-
-			// WriteLine $"[{stringSize} x i8] c{quotedString}, align {GetAggregateAlignment (1, stringSize)}"
-			Output.Write ('[');
-			Output.Write (stringSize);
-			Output.Write (" x i8] c");
-			Output.Write (quotedString);
-			Output.Write (", align ");
-			Output.WriteLine (GetAggregateAlignment (1, stringSize));
-
-			if (!global) {
+			StringSymbolInfo info = StringManager.Add (value, groupName: symbolName);
+			stringSize = info.Size;
+			if (!options.IsGlobal) {
 				return symbolName;
 			}
 
 			string indexType = Is64Bit ? "i64" : "i32";
 			WriteGlobalSymbolStart (symbolName, LlvmIrVariableOptions.GlobalConstantStringPointer);
-
-			// WriteLine $"i8* getelementptr inbounds ([{stringSize} x i8], [{stringSize} x i8]* @{strSymbolName}, {indexType} 0, {indexType} 0), align {GetAggregateAlignment (PointerSize, stringSize)}"
-			Output.Write ("i8* getelementptr inbounds ([");
-			Output.Write (stringSize);
-			Output.Write (" x i8], [");
-			Output.Write (stringSize);
-			Output.Write (" x i8]* @");
-			Output.Write (strSymbolName);
-			Output.Write (", ");
-			Output.Write (indexType);
-			Output.Write (" 0, ");
-			Output.Write (indexType);
-			Output.Write (" 0), align ");
+			WriteGetStringPointer (info.SymbolName, info.Size, indent: false, detectBitness: true);
+			Output.Write (", align ");
 			Output.WriteLine (GetAggregateAlignment (PointerSize, stringSize));
 
 			return symbolName;
 		}
 
-		/// <summary>
-		/// Writes a string, creating a new symbol if the <paramref name="value"/> is unique or returns name of a previously created symbol with the same
-		/// string value.  If a new symbol is written, its name is constructed by combining prefix (<paramref name="potentialSymbolNamePrefix"/>) with value
-		/// of a string counter referenced by the <paramref name="counter"/> parameter.  Symbol is created as a local, C++ constexpr style string.
-		/// </summary>
-		public StringSymbolInfo WriteUniqueString (string potentialSymbolName, string value, ref ulong counter)
-		{
-			return WriteUniqueString (potentialSymbolName, value, ref counter, LlvmIrVariableOptions.LocalConstexprString);
-		}
-
-		/// <summary>
-		/// Writes a string, creating a new symbol if the <paramref name="value"/> is unique or returns name of a previously created symbol with the same
-		/// string value.  If a new symbol is written, its name is constructed by combining prefix (<paramref name="potentialSymbolNamePrefix"/>) with value
-		/// of a string counter referenced by the <paramref name="counter"/> parameter.  Symbol options (writeability, visibility etc) are specified in the <paramref
-		/// name="options"/> parameter.  String size (in bytes) is returned in <paramref name="stringSize"/>.
-		/// </summary>
-		public StringSymbolInfo WriteUniqueString (string potentialSymbolNamePrefix, string value, ref ulong counter, LlvmIrVariableOptions options)
-		{
-			if (value == null) {
-				return null;
-			}
-
-			StringSymbolInfo info;
-			if (stringSymbolCache.TryGetValue (value, out info)) {
-				return info;
-			}
-
-			string newSymbolName = $"{potentialSymbolNamePrefix}.{counter++}";
-			WriteString (newSymbolName, value, options, out ulong stringSize);
-			info = new StringSymbolInfo (newSymbolName, stringSize);
-			stringSymbolCache.Add (value, info);
-
-			return info;
-		}
-
 		public virtual void WriteFileTop ()
 		{
 			WriteCommentLine ($"ModuleID = '{fileName}'");
@@ -1423,7 +1323,9 @@ public virtual void WriteFileTop ()
 		public virtual void WriteFileEnd ()
 		{
 			Output.WriteLine ();
+			StringManager.Flush (this);
 
+			Output.WriteLine ();
 			WriteAttributeSets ();
 
 			foreach (LlvmIrMetadataItem metadata in MetadataManager.Items) {