[llvm-objcopy] Fix bug in how segment alignment was being handled

Just aligning segment offsets to segment alignment is incorrect and also
wastes more space than is needed. The requirement is that p_offset ==
p_addr modulo p_align *not* that p_offset == 0 modulo p_align. Generally
speaking we've been using p_addr == 0 modulo p_align. In fact yaml2obj
can't even produce a valid situation which causes llvm-objcopy to
produce incorrect results because alignment and offset were both
inherited from the sections the program header covers. This change fixes
this bad behavior in llvm-objcopy.

Differential Revision: https://reviews.llvm.org/D39132

llvm-svn: 317284

1 files changed, 40 insertions, 0 deletions

diff --git a/llvm/test/tools/llvm-objcopy/check-addr-offset-align-binary.test b/llvm/test/tools/llvm-objcopy/check-addr-offset-align-binary.test
new file mode 100644
index 00000000000..755acceeda2
--- /dev/null
+++ b/llvm/test/tools/llvm-objcopy/check-addr-offset-align-binary.test
@@ -0,0 +1,40 @@
+# RUN: yaml2obj %s -o %t
+# RUN: llvm-objcopy -O binary %t %t2
+# RUN: od -t x1 %t2 | FileCheck %s
+
+!ELF
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  Type:            ET_EXEC
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    Address:         0x1000
+    AddressAlign:    0x0000000000001000
+    Content:         "c3c3c3c3"
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC ]
+    Address:         0x1008
+    AddressAlign:    0x0000000000000008
+    Content:         "3232"
+ProgramHeaders:
+  - Type: PT_LOAD
+    Flags: [ PF_X, PF_R ]
+    VAddr: 0x1000
+    PAddr: 0x1000
+    Align: 0x1000
+    Sections:
+      - Section: .text
+  - Type: PT_LOAD
+    Flags: [ PF_R, PF_W ]
+    VAddr: 0x1008
+    PAddr: 0x1008
+    Align: 0x1000
+    Sections:
+      - Section: .data
+
+# CHECK: 0000000 c3 c3 c3 c3 00 00 00 00 32 32