[PATCH] [llvm-symbolizer] Introduce the -dsym-hint option.

[Alexander Potapenko]

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Comment at: tools/llvm-symbolizer/LLVMSymbolize.cpp:320
@@ +319,3 @@
+  DsymPaths.push_back(getDarwinDWARFResourceForPath(ExePath, Filename));
+  for (const auto &path : Opts.DsymHints) {
+    DsymPaths.push_back(getDarwinDWARFResourceForPath(path, Filename));
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samsonov wrote:
> s/path/Path
Done

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Comment at: tools/llvm-symbolizer/LLVMSymbolize.cpp:356
@@ +355,3 @@
+    if (!Obj)
+      return std::make_pair(nullptr, nullptr);
+    addOwningBinary(std::move(B));
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samsonov wrote:
> We still need to cache (nullptr, nullptr) pair in ObjectPairForPathArch. For example, if the path is invalid and provided 50 times, we don't want to print diagnostics 50 times in error() function. So, at least in the way the code is structured now, we'll have to increase the indentation.
Added code that puts (nullptr, nullptr) into the map. Don't think increasing the indentation is better here.

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Comment at: tools/llvm-symbolizer/LLVMSymbolize.cpp:358
@@ -310,1 +357,3 @@
+    addOwningBinary(std::move(B));
     if (Bin->isMachO() || Bin->isMachOUniversalBinary()) {
+      if (auto MachObj = dyn_cast<const MachOObjectFile>(Obj))
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samsonov wrote:
> Do you need this check now? Looks like it's enough to check that Obj is a MachOObjectFile (and you won't need "Bin" variable in this case).
Removed the check.

http://reviews.llvm.org/D5705