labath created this revision.
labath added reviewers: clayborg, krytarowski, joerg.
Herald added subscribers: arichardson, emaste.
Herald added a reviewer: espindola.
The first section header does not define a real section. Instead it is
used for various elf extensions. This patch skips creation of a section
for index 0.
This has one furtunate side-effect, as it allows us to use the section
header index as the Section ID (where 0 is also invalid), and allows us
to get rid of a lot of spurious +1s in the ObjectFileELF code.
https://reviews.llvm.org/D55757
Files:
lit/Modules/ELF/many-sections.s
lit/Modules/MachO/subsections.yaml
source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
source/Plugins/ObjectFile/ELF/ObjectFileELF.h
tools/lldb-test/lldb-test.cpp
Index: tools/lldb-test/lldb-test.cpp
===================================================================
--- tools/lldb-test/lldb-test.cpp
+++ tools/lldb-test/lldb-test.cpp
@@ -732,6 +732,7 @@
assert(S);
AutoIndent Indent(Printer, 2);
Printer.formatLine("Index: {0}", I);
+ Printer.formatLine("ID: {0}", S->GetID());
Printer.formatLine("Name: {0}", S->GetName().GetStringRef());
Printer.formatLine("Type: {0}", S->GetTypeAsCString());
Printer.formatLine("Permissions: {0}", GetPermissionsAsCString(S->GetPermissions()));
Index: source/Plugins/ObjectFile/ELF/ObjectFileELF.h
===================================================================
--- source/Plugins/ObjectFile/ELF/ObjectFileELF.h
+++ source/Plugins/ObjectFile/ELF/ObjectFileELF.h
@@ -220,10 +220,10 @@
/// The address class for each symbol in the elf file
FileAddressToAddressClassMap m_address_class_map;
- /// Returns a 1 based index of the given section header.
+ /// Returns the index of the given section header.
size_t SectionIndex(const SectionHeaderCollIter &I);
- /// Returns a 1 based index of the given section header.
+ /// Returns the index of the given section header.
size_t SectionIndex(const SectionHeaderCollConstIter &I) const;
// Parses the ELF program headers.
Index: source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
===================================================================
--- source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -889,11 +889,11 @@
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollIter &I) {
- return std::distance(m_section_headers.begin(), I) + 1u;
+ return std::distance(m_section_headers.begin(), I);
}
size_t ObjectFileELF::SectionIndex(const SectionHeaderCollConstIter &I) const {
- return std::distance(m_section_headers.begin(), I) + 1u;
+ return std::distance(m_section_headers.begin(), I);
}
bool ObjectFileELF::ParseHeader() {
@@ -1081,7 +1081,7 @@
return 0;
// sh_link: section header index of string table used by entries in the
// section.
- Section *dynstr = section_list->FindSectionByID(header->sh_link + 1).get();
+ Section *dynstr = section_list->FindSectionByID(header->sh_link).get();
if (!dynstr)
return 0;
@@ -1717,10 +1717,10 @@
const ObjectFileELF::ELFSectionHeaderInfo *
ObjectFileELF::GetSectionHeaderByIndex(lldb::user_id_t id) {
- if (!id || !ParseSectionHeaders())
+ if (!ParseSectionHeaders())
return NULL;
- if (--id < m_section_headers.size())
+ if (id < m_section_headers.size())
return &m_section_headers[id];
return NULL;
@@ -1853,7 +1853,7 @@
m_sections_ap.reset(new SectionList());
VMAddressProvider address_provider(CalculateType());
- for (SectionHeaderCollIter I = m_section_headers.begin();
+ for (SectionHeaderCollIter I = std::next(m_section_headers.begin());
I != m_section_headers.end(); ++I) {
const ELFSectionHeaderInfo &header = *I;
@@ -2000,7 +2000,7 @@
symbol_type = eSymbolTypeUndefined;
break;
default:
- symbol_section_sp = section_list->GetSectionAtIndex(section_idx);
+ symbol_section_sp = section_list->FindSectionByID(section_idx);
break;
}
@@ -2282,9 +2282,8 @@
assert(symtab_hdr->sh_type == SHT_SYMTAB ||
symtab_hdr->sh_type == SHT_DYNSYM);
- // sh_link: section header index of associated string table. Section ID's are
- // ones based.
- user_id_t strtab_id = symtab_hdr->sh_link + 1;
+ // sh_link: section header index of associated string table.
+ user_id_t strtab_id = symtab_hdr->sh_link;
Section *strtab = section_list->FindSectionByID(strtab_id).get();
if (symtab && strtab) {
@@ -2494,10 +2493,6 @@
if (!symtab_id || !plt_id)
return 0;
- // Section ID's are ones based;
- symtab_id++;
- plt_id++;
-
const ELFSectionHeaderInfo *plt_hdr = GetSectionHeaderByIndex(plt_id);
if (!plt_hdr)
return 0;
@@ -2523,7 +2518,7 @@
return 0;
// sh_link points to associated string table.
- Section *strtab = section_list->FindSectionByID(sym_hdr->sh_link + 1).get();
+ Section *strtab = section_list->FindSectionByID(sym_hdr->sh_link).get();
if (!strtab)
return 0;
@@ -2651,9 +2646,8 @@
if (!section_list)
return 0;
- // Section ID's are ones based.
- user_id_t symtab_id = rel_hdr->sh_link + 1;
- user_id_t debug_id = rel_hdr->sh_info + 1;
+ user_id_t symtab_id = rel_hdr->sh_link;
+ user_id_t debug_id = rel_hdr->sh_info;
const ELFSectionHeader *symtab_hdr = GetSectionHeaderByIndex(symtab_id);
if (!symtab_hdr)
Index: lit/Modules/MachO/subsections.yaml
===================================================================
--- lit/Modules/MachO/subsections.yaml
+++ lit/Modules/MachO/subsections.yaml
@@ -3,6 +3,7 @@
#CHECK: Showing 2 sections
#CHECK-NEXT: Index: 0
+#CHECK-NEXT: ID: 256
#CHECK-NEXT: Name: __PAGEZERO
#CHECK-NEXT: Type: container
#CHECK-NEXT: Permissions: ---
@@ -13,6 +14,7 @@
#CHECK-NEXT: There are no subsections
#CHECK-EMPTY:
#CHECK-NEXT: Index: 1
+#CHECK-NEXT: ID: 512
#CHECK-NEXT: Name: __TEXT
#CHECK-NEXT: Type: container
#CHECK-NEXT: Permissions: r-x
@@ -22,6 +24,7 @@
#CHECK-NEXT: File size: 4096
#CHECK-NEXT: Showing 3 subsections
#CHECK-NEXT: Index: 0
+#CHECK-NEXT: ID: 1
#CHECK-NEXT: Name: __text
#CHECK-NEXT: Type: code
#CHECK-NEXT: Permissions: r-x
@@ -31,6 +34,7 @@
#CHECK-NEXT: File size: 22
#CHECK-EMPTY:
#CHECK-NEXT: Index: 1
+#CHECK-NEXT: ID: 2
#CHECK-NEXT: Name: __unwind_info
#CHECK-NEXT: Type: compact-unwind
#CHECK-NEXT: Permissions: r-x
@@ -40,6 +44,7 @@
#CHECK-NEXT: File size: 76
#CHECK-EMPTY:
#CHECK-NEXT: Index: 2
+#CHECK-NEXT: ID: 3
#CHECK-NEXT: Name: __eh_frame
#CHECK-NEXT: Type: eh-frame
#CHECK-NEXT: Permissions: r-x
Index: lit/Modules/ELF/many-sections.s
===================================================================
--- lit/Modules/ELF/many-sections.s
+++ lit/Modules/ELF/many-sections.s
@@ -7,7 +7,7 @@
## aaaaaaaa..dddddddd, plus a couple of standard ones (.strtab, etc.)
## Check the number is correct plus the names of a couple of chosen sections.
-# CHECK: Showing 65541 sections
+# CHECK: Showing 65540 sections
# CHECK: Name: aaaaaaaa
# CHECK: Name: bbbbbbbb
# CHECK: Name: cccccccc
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