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Fixes symbol resolution for a function with a tail call because the PC

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for the frame is one past the address range of the calling function.
- Lowers the fix from RegisterContextLLDB for use with disassembly
- Fixes one of three issues in the disassembly test in TestInferiorAssert.py

Also adds documentation that explains the resolution depths and interface.

Note: This change affects the resolution scope for eSymbolContextFunction
without impacting the performance of eSymbolContextSymbol.

Thanks to Matt Kopec for his review.

llvm-svn: 190812
This commit is contained in:
Ashok Thirumurthi
2013-09-16 22:00:17 +00:00
parent 52694e3bb8
commit 3880714172
3 changed files with 79 additions and 34 deletions
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52
lldb/source/Core/Module.cpp
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@@ -468,6 +468,10 @@ Module::ResolveSymbolContextForAddress (const Address& so_addr, uint32_t resolve
sc.module_sp = shared_from_this();
resolved_flags |= eSymbolContextModule;
SymbolVendor* sym_vendor = GetSymbolVendor();
if (!sym_vendor)
return resolved_flags;
// Resolve the compile unit, function, block, line table or line
// entry if requested.
if (resolve_scope & eSymbolContextCompUnit ||
@@ -475,25 +479,51 @@ Module::ResolveSymbolContextForAddress (const Address& so_addr, uint32_t resolve
resolve_scope & eSymbolContextBlock ||
resolve_scope & eSymbolContextLineEntry )
{
SymbolVendor *symbols = GetSymbolVendor ();
if (symbols)
resolved_flags |= symbols->ResolveSymbolContext (so_addr, resolve_scope, sc);
resolved_flags |= sym_vendor->ResolveSymbolContext (so_addr, resolve_scope, sc);
}
// Resolve the symbol if requested, but don't re-look it up if we've already found it.
if (resolve_scope & eSymbolContextSymbol && !(resolved_flags & eSymbolContextSymbol))
{
SymbolVendor* sym_vendor = GetSymbolVendor();
if (sym_vendor)
Symtab *symtab = sym_vendor->GetSymtab();
if (symtab && so_addr.IsSectionOffset())
{
Symtab *symtab = sym_vendor->GetSymtab();
if (symtab)
sc.symbol = symtab->FindSymbolContainingFileAddress(so_addr.GetFileAddress());
if (sc.symbol)
resolved_flags |= eSymbolContextSymbol;
}
}
// For function symbols, so_addr may be off by one. This is a convention consistent
// with FDE row indices in eh_frame sections, but requires extra logic here to permit
// symbol lookup for disassembly and unwind.
if (resolve_scope & eSymbolContextSymbol && !(resolved_flags & eSymbolContextSymbol) &&
resolve_scope & eSymbolContextFunction && !(resolved_flags & eSymbolContextFunction) &&
so_addr.GetOffset() > 0)
{
Address previous_addr = so_addr;
previous_addr.SetOffset(so_addr.GetOffset() - 1);
const uint32_t flags = sym_vendor->ResolveSymbolContext (previous_addr, resolve_scope, sc);
if (flags & eSymbolContextSymbol)
{
AddressRange addr_range;
if (sc.GetAddressRange (eSymbolContextFunction | eSymbolContextSymbol, 0, false, addr_range))
{
if (so_addr.IsSectionOffset())
if (addr_range.GetBaseAddress().GetSection() == so_addr.GetSection())
{
sc.symbol = symtab->FindSymbolContainingFileAddress(so_addr.GetFileAddress());
if (sc.symbol)
resolved_flags |= eSymbolContextSymbol;
// If the requested address is one past the address range of a function (i.e. a tail call),
// or the decremented address is the start of a function (i.e. some forms of trampoline),
// indicate that the symbol has been resolved.
if (so_addr.GetOffset() == addr_range.GetBaseAddress().GetOffset() ||
so_addr.GetOffset() == addr_range.GetBaseAddress().GetOffset() + addr_range.GetByteSize())
{
resolved_flags |= flags;
}
}
else
{
sc.symbol = nullptr; // Don't trust the symbol if the sections didn't match.
}
}
}