[yaml2obj] - Verify that sections are sorted by their file offsets wh…

…en creating segments. This validates that sections listed for a segment in the YAML declaration are ordered by their file offsets. It might help to simplify the file size computation, but also is useful by itself as helps to avoid issues in test cases and to maintain their readability. Differential revision: https://reviews.llvm.org/D78361
llvm · Apr 21, 2020 · 3471ae9 · 3471ae9
1 parent c3a2929
commit 3471ae9
Show file tree

Hide file tree

Showing 7 changed files with 68 additions and 6 deletions.
diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -753,6 +753,11 @@ void ELFState<ELFT>::setProgramHeaderLayout(std::vector<Elf_Phdr> &PHeaders,
   for (auto &YamlPhdr : Doc.ProgramHeaders) {
     Elf_Phdr &PHeader = PHeaders[PhdrIdx++];
     std::vector<Fragment> Fragments = getPhdrFragments(YamlPhdr, SHeaders);
+    if (!llvm::is_sorted(Fragments, [](const Fragment &A, const Fragment &B) {
+          return A.Offset < B.Offset;
+        }))
+      reportError("sections in the program header with index " +
+                  Twine(PhdrIdx) + " are not sorted by their file offset");
 
     if (YamlPhdr.Offset) {
       PHeader.p_offset = *YamlPhdr.Offset;

diff --git a/llvm/test/tools/llvm-gsymutil/X86/elf-dwarf.yaml b/llvm/test/tools/llvm-gsymutil/X86/elf-dwarf.yaml
@@ -395,8 +395,6 @@ ProgramHeaders:
       - Section: .note.ABI-tag
       - Section: .note.gnu.build-id
       - Section: .gnu.hash
-      - Section: .dynsym
-      - Section: .dynstr
       - Section: .gnu.version
       - Section: .gnu.version_r
       - Section: .rela.dyn
@@ -409,6 +407,8 @@ ProgramHeaders:
       - Section: .rodata
       - Section: .eh_frame_hdr
       - Section: .eh_frame
+      - Section: .dynsym
+      - Section: .dynstr
 Symbols:
   - Name:            .interp
     Type:            STT_SECTION

diff --git a/llvm/test/tools/llvm-readobj/ELF/demangle.test b/llvm/test/tools/llvm-readobj/ELF/demangle.test
@@ -213,8 +213,8 @@ ProgramHeaders:
     Flags: [ PF_R, PF_X ]
     VAddr: 0x0
     Sections:
-      - Section: .dynsym
       - Section: .dynstr
+      - Section: .dynsym
       - Section: .rela.dyn
       - Section: .dynamic
       - Section: .text.foo

diff --git a/llvm/test/tools/llvm-readobj/ELF/hash-symbols.test b/llvm/test/tools/llvm-readobj/ELF/hash-symbols.test
@@ -298,8 +298,8 @@ ProgramHeaders:
     Flags: [ PF_R, PF_X ]
     VAddr: 0x0
     Sections:
-      - Section: .dynsym
       - Section: .dynstr
+      - Section: .dynsym
       - Section: .dynamic
       - Section: .text.foo
   - Type:  PT_DYNAMIC

diff --git a/llvm/test/tools/llvm-readobj/ELF/reloc-negative-addend-no-sym.test b/llvm/test/tools/llvm-readobj/ELF/reloc-negative-addend-no-sym.test
@@ -65,8 +65,8 @@ ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
-      - Section: .rela.dyn
       - Section: .dynamic
+      - Section: .rela.dyn
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:

diff --git a/llvm/test/tools/llvm-readobj/ELF/reloc-zero-name-or-value.test b/llvm/test/tools/llvm-readobj/ELF/reloc-zero-name-or-value.test
@@ -101,8 +101,8 @@ ProgramHeaders:
   - Type: PT_LOAD
     VAddr: 0x1000
     Sections:
-      - Section: .rela.dyn
       - Section: .dynamic
+      - Section: .rela.dyn
   - Type: PT_DYNAMIC
     VAddr: 0x1000
     Sections:

diff --git a/llvm/test/tools/obj2yaml/program-headers.yaml b/llvm/test/tools/obj2yaml/program-headers.yaml
@@ -517,3 +517,60 @@ Sections:
 ## Use an arbitrary size that is different to the size of
 ## the previous section.
     Size:    0x20
+
+## Check that we require sections in a program header
+## declaration to be sorted by their offsets.
+# RUN: not yaml2obj --docnum=6 %s -o %t6 2>&1 | \
+# RUN:   FileCheck %s --check-prefix=UNSORTED --implicit-check-not="error:"
+
+# UNSORTED:      error: sections in the program header with index 1 are not sorted by their file offset
+# UNSORTED-NEXT: error: sections in the program header with index 3 are not sorted by their file offset
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_DYN
+  Machine: EM_X86_64
+ProgramHeaders:
+## Case 1: the .bar section is placed after the .foo section in the file.
+##         Check we report an error about the violation of the order.
+  - Type:  PT_LOAD
+    Flags: [ PF_R ]
+    Sections:
+      - Section: .bar
+      - Section: .foo
+    VAddr:  0x1000
+## There is nothing wrong with this segment. We have it to show that
+## we report correct program header indices in error messages.
+  - Type:  PT_LOAD
+    Flags: [ PF_R ]
+    Sections:
+      - Section: .foo
+      - Section: .bar
+    VAddr:  0x1000
+## Case 2: the .bar section is placed before the .zed section in the file,
+##         but the sh_offset of .zed is less than the sh_offset of
+##         the .bar section because of the "ShOffset" property.
+##         Document we report an error for such a case.
+  - Type:  PT_LOAD
+    Flags: [ PF_R ]
+    Sections:
+      - Section: .bar
+      - Section: .zed
+    VAddr:  0x1001
+Sections:
+  - Name:    .foo
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC ]
+    Size:    0x1
+    Address: 0x1000
+  - Name:    .bar
+    Type:    SHT_PROGBITS
+    Flags:   [ SHF_ALLOC ]
+    Size:    0x1
+  - Name:     .zed
+    Type:     SHT_PROGBITS
+    Flags:    [ SHF_ALLOC ]
+    Size:     0x1
+    ShOffset: 0x0