Databases
StackOverflow2013
Postsdbo
POWhy does sun C++ compiler change symbol names when compiling with debug infos?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
    primarykey
    data
    text
    <p>I have this source file:</p> <pre><code>// ConstPointer.cpp const short * const const_short_p_const = 0; const short * const_short_p = 0; </code></pre> <p>and compiled it with and without debug infos (SUN C++ Compiler 5.10):</p> <pre><code># CC ConstPointer.cpp -c -o ConstPointer.o # CC -g ConstPointer.cpp -c -o ConstPointer-debug.o </code></pre> <p>Here are the symbol names of the object file <strong>without</strong> debug information:</p> <pre><code># nm -C ConstPointer.o ConstPointer.o: [Index] Value Size Type Bind Other Shndx Name [2] | 0| 0|SECT |LOCL |0 |10 | [3] | 0| 0|SECT |LOCL |0 |9 | [4] | 0| 0|OBJT |LOCL |0 |6 |Bbss.bss [1] | 0| 0|FILE |LOCL |0 |ABS |ConstPointer.cpp [5] | 0| 0|OBJT |LOCL |0 |3 |Ddata.data [6] | 0| 0|OBJT |LOCL |0 |5 |Dpicdata.picdata [7] | 0| 0|OBJT |LOCL |0 |4 |Drodata.rodata [9] | 4| 4|OBJT |GLOB |0 |3 |const_short_p [8] | 0| 4|OBJT |LOCL |0 |3 |const_short_p_const </code></pre> <p>Here are the symbol names of the object file <strong>with</strong> debug information:</p> <pre><code># nm -C ConstPointer-debug.o ConstPointer-debug.o: [Index] Value Size Type Bind Other Shndx Name [4] | 0| 0|SECT |LOCL |0 |9 | [2] | 0| 0|SECT |LOCL |0 |8 | [3] | 0| 0|SECT |LOCL |0 |10 | [10] | 0| 4|OBJT |GLOB |0 |3 |$XAHMCqApZlqO37H.const_short_p_const [5] | 0| 0|NOTY |LOCL |0 |6 |Bbss.bss [1] | 0| 0|FILE |LOCL |0 |ABS |ConstPointer.cpp [6] | 0| 0|NOTY |LOCL |0 |3 |Ddata.data [7] | 0| 0|NOTY |LOCL |0 |5 |Dpicdata.picdata [8] | 0| 0|NOTY |LOCL |0 |4 |Drodata.rodata [9] | 4| 4|OBJT |GLOB |0 |3 |const_short_p </code></pre> <p>Why has the variable <code>const_short_p_const</code> another symbol name? <code>g++</code> does not change it, when compiling with debug information. It looks like a compiler bug to me. What do you think? The second <code>const</code> (constant pointer) leads to this.</p> <p><strong>EDIT for Drew Hall's comment:</strong> For example you have two files:</p> <pre><code>// ConstPointer.cpp const short * const const_short_p_const = 0; void foo(); int main(int argc, const char *argv[]) { foo(); return 0; } </code></pre> <p>and</p> <pre><code>// ConstPointer2.cpp extern const short * const const_short_p_const; void foo() { short x = *const_short_p_const; } </code></pre> <p>Compiling is fine:</p> <pre><code># CC ConstPointer2.cpp -g -c -o ConstPointer2.o # CC ConstPointer.cpp -g -c -o ConstPointer.o </code></pre> <p>but linking does not work because the symbols differ! The symbol name in ConstPointer2.o is <code>const_short_p_const</code>, but the symbol name in ConstPointer.o is <code>$XAHMCqApZlqO37H.const_short_p_const</code>.</p> <pre><code># CC ConstPointer.o ConstPointer2.o -o ConstPointer Undefined first referenced symbol in file const_short_p_const ConstPointer2.o </code></pre>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USmichael.kebe
    1. USmichael.kebe
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThis is purely an implementation detail--why are you concerned with the generated symbol names?
      singulars
      1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
      1. USDrew Hall
    2. CO@DrewHall See the edit.
      singulars
      1. POWhy does sun C++ compiler change symbol names when compiling with debug infos?
      1. USmichael.kebe
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload