<div dir="ltr"><div>Sure, here you go:</div><div><br></div><div>$ cat tmp/debug_ranges/a.cc</div><div>int global = 2;</div><div>int foo(int bar) { return bar; }</div><div>int foo2(int bar2) { return bar2; }</div><div><br></div>
<div>int main() {</div><div> return foo(2) + foo2(1) + global;</div><div>}</div><div>$ ./bin/clang++ -g -O1 tmp/debug_ranges/a.cc<br></div><div><div>$ readelf -wr a.out</div><div>Contents of the .debug_aranges section:</div>
<div><br></div><div> Length: 92</div><div> Version: 2</div><div> Offset into .debug_info: 0x0</div><div> Pointer Size: 8</div><div> Segment Size: 0</div><div>
<br></div><div> Address Length</div><div> 0000000000000000 0000000000000001 <----- huh?</div><div> 0000000000000036 0000000000000001 <----- hm?</div><div> 0000000000402018 0000000000000004 </div>
<div> 0000000000400510 0000000000000041 </div><div> 0000000000000000 0000000000000000 </div></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Wed, Oct 2, 2013 at 10:23 PM, Richard Mitton <span dir="ltr"><<a href="mailto:richard@codersnotes.com" target="_blank">richard@codersnotes.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">How would I go about reproducing this bug? I'd really like to see a test case.<span class="HOEnZb"><font color="#888888"><br>
<br>
Richard Mitton<br>
<a href="mailto:richard@codersnotes.com" target="_blank">richard@codersnotes.com</a></font></span><div class="HOEnZb"><div class="h5"><br>
<br>
On 10/02/2013 07:10 AM, Alexey Samsonov wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi echristo,<br>
<br>
r191052 added emitting .debug_aranges to Clang, but this<br>
functionality is broken: it uses all MC labels added in DWARF Asm<br>
printer, including the labels for build relocations between<br>
different DWARF sections, like .Lsection_line or .Ldebug_loc0.<br>
<br>
As a result, if any DIE .debug_info would contain "DW_AT_location=0x123"<br>
attribute, .debug_aranges would also contain a range starting from 0x123,<br>
breaking tools that rely on this section.<br>
<br>
I'm not sure this is the correct fix, please take a look.<br>
<br>
<a href="http://llvm-reviews.chandlerc.com/D1809" target="_blank">http://llvm-reviews.chandlerc.<u></u>com/D1809</a><br>
<br>
Files:<br>
lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.cpp<br>
lib/CodeGen/AsmPrinter/<u></u>DwarfCompileUnit.cpp<br>
lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.h<br>
<br>
Index: lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.cpp<br>
==============================<u></u>==============================<u></u>=======<br>
--- lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.cpp<br>
+++ lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.cpp<br>
@@ -1110,8 +1110,8 @@<br>
void DwarfDebug::endSections() {<br>
// Filter labels by section.<br>
- for (size_t n = 0; n < Labels.size(); n++) {<br>
- const SymbolCU &SCU = Labels[n];<br>
+ for (size_t n = 0; n < ArangeLabels.size(); n++) {<br>
+ const SymbolCU &SCU = ArangeLabels[n];<br>
if (SCU.Sym->isInSection()) {<br>
// Make a note of this symbol and it's section.<br>
const MCSection *Section = &SCU.Sym->getSection();<br>
@@ -1138,10 +1138,7 @@<br>
}<br>
// Insert a final terminator.<br>
- SymbolCU Entry;<br>
- Entry.CU = NULL;<br>
- Entry.Sym = Sym;<br>
- SectionMap[Section].push_back(<u></u>Entry);<br>
+ SectionMap[Section].push_back(<u></u>SymbolCU(NULL, Sym));<br>
}<br>
}<br>
Index: lib/CodeGen/AsmPrinter/<u></u>DwarfCompileUnit.cpp<br>
==============================<u></u>==============================<u></u>=======<br>
--- lib/CodeGen/AsmPrinter/<u></u>DwarfCompileUnit.cpp<br>
+++ lib/CodeGen/AsmPrinter/<u></u>DwarfCompileUnit.cpp<br>
@@ -181,26 +181,15 @@<br>
const MCSymbol *Label) {<br>
DIEValue *Value = new (DIEValueAllocator) DIELabel(Label);<br>
Die->addValue(Attribute, Form, Value);<br>
-<br>
- SymbolCU Entry;<br>
- Entry.CU = this;<br>
- Entry.Sym = Label;<br>
-<br>
- DD->addLabel(Entry);<br>
}<br>
/// addLabelAddress - Add a dwarf label attribute data and value using<br>
/// DW_FORM_addr or DW_FORM_GNU_addr_index.<br>
///<br>
void CompileUnit::addLabelAddress(<u></u>DIE *Die, uint16_t Attribute,<br>
MCSymbol *Label) {<br>
- if (Label) {<br>
- SymbolCU Entry;<br>
- Entry.CU = this;<br>
- Entry.Sym = Label;<br>
-<br>
- DD->addLabel(Entry);<br>
- }<br>
+ if (Label)<br>
+ DD->addArangeLabel(SymbolCU(<u></u>this, Label));<br>
if (!DD->useSplitDwarf()) {<br>
if (Label != NULL) {<br>
@@ -221,6 +210,7 @@<br>
/// form given and an op of either DW_FORM_addr or DW_FORM_GNU_addr_index.<br>
///<br>
void CompileUnit::addOpAddress(DIE *Die, const MCSymbol *Sym) {<br>
+ DD->addArangeLabel(SymbolCU(<u></u>this, Sym));<br>
if (!DD->useSplitDwarf()) {<br>
addUInt(Die, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);<br>
addLabel(Die, 0, dwarf::DW_FORM_udata, Sym);<br>
Index: lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.h<br>
==============================<u></u>==============================<u></u>=======<br>
--- lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.h<br>
+++ lib/CodeGen/AsmPrinter/<u></u>DwarfDebug.h<br>
@@ -303,6 +303,7 @@<br>
/// \brief Helper used to pair up a symbol and it's DWARF compile unit.<br>
struct SymbolCU {<br>
+ SymbolCU(CompileUnit *CU, const MCSymbol *Sym) : Sym(Sym), CU(CU) {}<br>
const MCSymbol *Sym;<br>
CompileUnit *CU;<br>
};<br>
@@ -363,8 +364,8 @@<br>
// separated by a zero byte, mapped to a unique id.<br>
StringMap<unsigned, BumpPtrAllocator&> SourceIdMap;<br>
- // List of all labels used in the output.<br>
- std::vector<SymbolCU> Labels;<br>
+ // List of all labels used in aranges generation.<br>
+ std::vector<SymbolCU> ArangeLabels;<br>
// Size of each symbol emitted (for those symbols that have a specific size).<br>
DenseMap <const MCSymbol *, uint64_t> SymSize;<br>
@@ -731,7 +732,7 @@<br>
void addTypeUnitType(DIE *Die) { TypeUnits.push_back(Die); }<br>
/// \brief Add a label so that arange data can be generated for it.<br>
- void addLabel(SymbolCU SCU) { Labels.push_back(SCU); }<br>
+ void addArangeLabel(SymbolCU SCU) { ArangeLabels.push_back(SCU); }<br>
/// \brief For symbols that have a size designated (e.g. common symbols),<br>
/// this tracks that size.<br>
</blockquote>
<br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div>Alexey Samsonov, MSK</div>
</div>