From ca7aa99f983390f2997f478c86819a4dc69487be Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Wed, 12 Jan 2011 12:43:13 +0000
Subject: [PATCH] * Added SymbolLookupInfo::requestingSymbol which is passed in
 by   resolve_symbol(). * find_undefined_symbol_beos(): Does now check whether
   SymbolLookupInfo::requestingSymbol is defined, and, if so, returns it  
 directly. This saves the time for the hash table lookup and also works  
 around broken files like SoundPlay. Fixes the runtime loader part of #7094.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@40211 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../runtime_loader/elf_symbol_lookup.cpp       | 18 +++++++++++++++---
 src/system/runtime_loader/elf_symbol_lookup.h  | 13 +++++++++----
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/src/system/runtime_loader/elf_symbol_lookup.cpp b/src/system/runtime_loader/elf_symbol_lookup.cpp
index 9d4788e87d..8716db1d41 100644
--- a/src/system/runtime_loader/elf_symbol_lookup.cpp
+++ b/src/system/runtime_loader/elf_symbol_lookup.cpp
@@ -109,7 +109,7 @@ find_symbol(image_t* image, const SymbolLookupInfo& lookupInfo)
 		Elf32_Sym* symbol = &image->syms[i];
 
 		if (symbol->st_shndx != SHN_UNDEF
-			&& ((ELF32_ST_BIND(symbol->st_info)== STB_GLOBAL)
+			&& ((ELF32_ST_BIND(symbol->st_info) == STB_GLOBAL)
 				|| (ELF32_ST_BIND(symbol->st_info) == STB_WEAK))
 			&& !strcmp(SYMNAME(image, symbol), lookupInfo.name)) {
 
@@ -300,13 +300,25 @@ find_undefined_symbol_beos(image_t* rootImage, image_t* image,
 {
 	// BeOS style symbol resolution: It is sufficient to check the image itself
 	// and its direct dependencies. The linker would have complained, if the
-	// symbol wasn't there.
+	// symbol wasn't there. First we check whether the requesting symbol is
+	// defined already -- then we can simply return it, since, due to symbolic
+	// linking, that's the one we'd find anyway.
+	if (Elf32_Sym* symbol = lookupInfo.requestingSymbol) {
+		if (symbol->st_shndx != SHN_UNDEF
+			&& ((ELF32_ST_BIND(symbol->st_info) == STB_GLOBAL)
+				|| (ELF32_ST_BIND(symbol->st_info) == STB_WEAK))) {
+			return symbol;
+		}
+	}
+
+	// lookup in image
 	Elf32_Sym* symbol = find_symbol(image, lookupInfo);
 	if (symbol != NULL) {
 		*foundInImage = image;
 		return symbol;
 	}
 
+	// lookup in dependencies
 	for (uint32 i = 0; i < image->num_needed; i++) {
 		if (image->needed[i]->dynamic_ptr) {
 			symbol = find_symbol(image->needed[i], lookupInfo);
@@ -479,7 +491,7 @@ resolve_symbol(image_t* rootImage, image_t* image, struct Elf32_Sym* sym,
 
 		// search the symbol
 		sharedSym = rootImage->find_undefined_symbol(rootImage, image,
-			SymbolLookupInfo(symName, type, versionInfo), &sharedImage);
+			SymbolLookupInfo(symName, type, versionInfo, 0, sym), &sharedImage);
 	}
 
 	enum {
diff --git a/src/system/runtime_loader/elf_symbol_lookup.h b/src/system/runtime_loader/elf_symbol_lookup.h
index e9117d4740..3f2791317f 100644
--- a/src/system/runtime_loader/elf_symbol_lookup.h
+++ b/src/system/runtime_loader/elf_symbol_lookup.h
@@ -25,26 +25,31 @@ struct SymbolLookupInfo {
 	uint32					hash;
 	uint32					flags;
 	const elf_version_info*	version;
+	Elf32_Sym*				requestingSymbol;
 
 	SymbolLookupInfo(const char* name, int32 type, uint32 hash,
-		const elf_version_info* version = NULL, uint32 flags = 0)
+		const elf_version_info* version = NULL, uint32 flags = 0,
+		Elf32_Sym* requestingSymbol = NULL)
 		:
 		name(name),
 		type(type),
 		hash(hash),
 		flags(flags),
-		version(version)
+		version(version),
+		requestingSymbol(requestingSymbol)
 	{
 	}
 
 	SymbolLookupInfo(const char* name, int32 type,
-		const elf_version_info* version = NULL, uint32 flags = 0)
+		const elf_version_info* version = NULL, uint32 flags = 0,
+		Elf32_Sym* requestingSymbol = NULL)
 		:
 		name(name),
 		type(type),
 		hash(elf_hash(name)),
 		flags(flags),
-		version(version)
+		version(version),
+		requestingSymbol(requestingSymbol)
 	{
 	}
 };