[hsa-runtime] Add support to hsa-runtime to find symbols from ".dynsym" section.

Earlier, hsa-runtime was unable to find symbols from a stripped ELF-image becasue
no support to find symbols from ".dynsym" section.

Looking for symbols in .dynsym is enabled by LOADER_USE_DYNSYM=1
environment variable

Change-Id: I4f0e8dd0eb053a6066d4d49b670c52e51149531a


[ROCm/ROCR-Runtime commit: 4142a77375]

projects/rocr-runtime/runtime/hsa-runtime/core/inc/amd_elf_image.hpp

@@ -183,6 +183,10 @@ namespace elf {
       virtual StringTable* strtab() = 0;
       virtual SymbolTable* symtab() = 0;
       virtual SymbolTable* getSymtab(uint16_t index) = 0;
+      virtual SymbolTable* dynsym() = 0;
+      virtual SymbolTable* getDynsym(uint16_t index) = 0;
+      virtual SymbolTable* getSymbolTable() = 0;
+      virtual SymbolTable* getSymbolTable(uint16_t index) = 0;
 
       virtual StringTable* addStringTable(const std::string& name) = 0;
       virtual StringTable* getStringTable(uint16_t index) = 0;

projects/rocr-runtime/runtime/hsa-runtime/libamdhsacode/amd_elf_image.cpp

@@ -713,7 +713,24 @@ namespace elf {
       GElfStringTable* strtab() override;
       GElfSymbolTable* getSymtab(uint16_t index) override
       {
-        return static_cast<GElfSymbolTable*>(section(index));
+        if (section(index)->type() == SHT_SYMTAB)
+          return static_cast<GElfSymbolTable*>(section(index));
+        return nullptr;
+      }
+      GElfSymbolTable* getDynsym(uint16_t index) override
+      {
+        if (section(index)->type() == SHT_DYNSYM)
+          return static_cast<GElfSymbolTable*>(section(index));
+        return nullptr;
+      }
+
+      GElfSymbolTable* getSymbolTable() override;
+      GElfSymbolTable* getSymbolTable(uint16_t index) override
+      {
+        const char *UseDynsym = getenv("LOADER_USE_DYNSYM");
+        if (UseDynsym && std::strncmp(UseDynsym, "0", 1) != 0)
+          return getDynsym(index);
+        return getSymtab(index);
       }
 
       GElfStringTable* addStringTable(const std::string& name) override;
@@ -721,6 +738,7 @@ namespace elf {
 
       GElfSymbolTable* addSymbolTable(const std::string& name, StringTable* stab = 0) override;
       GElfSymbolTable* symtab() override;
+      GElfSymbolTable* dynsym() override;
 
       GElfSegment* segment(size_t i) override { return segments[i].get(); }
       Segment* segmentByVAddr(uint64_t vaddr) override;
@@ -759,6 +777,7 @@ namespace elf {
       GElfStringTable* shstrtabSection;
       GElfStringTable* strtabSection;
       GElfSymbolTable* symtabSection;
+      GElfSymbolTable* dynsymSection;
       GElfNoteSection* noteSection;
       std::vector<std::unique_ptr<GElfSegment>> segments;
       std::vector<std::unique_ptr<GElfSection>> sections;
@@ -1261,6 +1280,7 @@ namespace elf {
         e(0),
         shstrtabSection(0), strtabSection(0),
         symtabSection(0),
+        dynsymSection(0),
         noteSection(0)
     {
       if (EV_NONE == elf_version(EV_CURRENT)) {
@@ -1436,6 +1456,7 @@ namespace elf {
         if (section->type() == SHT_STRTAB) { strtabSection = static_cast<GElfStringTable*>(section.get()); }
         if (section->type() == SHT_SYMTAB) { symtabSection = static_cast<GElfSymbolTable*>(section.get()); }
         if (section->type() == SHT_NOTE) { noteSection = static_cast<GElfNoteSection*>(section.get()); }
+        if (section->type() == SHT_DYNSYM) { dynsymSection = static_cast<GElfSymbolTable*>(section.get()); }
       }
 
       size_t phnum;
@@ -1553,7 +1574,7 @@ namespace elf {
       }
     }
 
-    GElfStringTable* GElfImage::addStringTable(const std::string& name) 
+    GElfStringTable* GElfImage::addStringTable(const std::string& name)
     {
       GElfStringTable* stab = new GElfStringTable(this);
       sections.push_back(std::unique_ptr<GElfStringTable>(stab));
@@ -1597,6 +1618,21 @@ namespace elf {
       return symtabSection;
     }
 
+    GElfSymbolTable* GElfImage::dynsym()
+    {
+      if (!dynsymSection) {
+        dynsymSection = addSymbolTable(".dynsym", strtab());
+      }
+      return dynsymSection;
+    }
+
+    GElfSymbolTable* GElfImage::getSymbolTable()
+    {
+      const char *UseDynsym = getenv("LOADER_USE_DYNSYM");
+      if (UseDynsym && std::strncmp(UseDynsym, "0", 1) != 0)
+        return dynsym();
+      return symtab();
+    }
 
     GElfNoteSection* GElfImage::note()
     {

projects/rocr-runtime/runtime/hsa-runtime/libamdhsacode/amd_hsa_code.cpp

@@ -1765,8 +1765,8 @@ namespace code {
           hsatext = sec;
         }
       }
-      for (size_t i = 0; i < img->symtab()->symbolCount(); ++i) {
-        amd::elf::Symbol* elfsym = img->symtab()->symbol(i);
+      for (size_t i = 0; i < img->getSymbolTable()->symbolCount(); ++i) {
+        amd::elf::Symbol* elfsym = img->getSymbolTable()->symbol(i);
         Symbol* sym = 0;
         switch (elfsym->type()) {
         case STT_AMDGPU_HSA_KERNEL: {