[llvm] e1babfc - Revert "[MC][ELF] Work around R_MIPS_LO16 relocation handling problem"

[Dimitry Andric via llvm-commits]

Author: Dimitry Andric
Date: 2021-05-03T23:08:04+02:00
New Revision: e1babfc2233bf725b7c3c4e1a5af2ba79bfaddd5

URL: https://github.com/llvm/llvm-project/commit/e1babfc2233bf725b7c3c4e1a5af2ba79bfaddd5
DIFF: https://github.com/llvm/llvm-project/commit/e1babfc2233bf725b7c3c4e1a5af2ba79bfaddd5.diff

LOG: Revert "[MC][ELF] Work around R_MIPS_LO16 relocation handling problem"

This reverts commit ab40c027f0ce9492919a72ad339de40bdb84b354.

Some additional test cases are influenced by the workaround, and I need
to do a complete test run to identify and check them all.

Added: 
    

Modified: 
    llvm/lib/MC/ELFObjectWriter.cpp

Removed: 
    llvm/test/MC/Mips/mips_lo16.s


################################################################################
diff  --git a/llvm/lib/MC/ELFObjectWriter.cpp b/llvm/lib/MC/ELFObjectWriter.cpp
index 534c263d735c..dd36aec112e5 100644
--- a/llvm/lib/MC/ELFObjectWriter.cpp
+++ b/llvm/lib/MC/ELFObjectWriter.cpp
@@ -1381,17 +1381,6 @@ bool ELFObjectWriter::shouldRelocateWithSymbol(const MCAssembler &Asm,
       if (TargetObjectWriter->getEMachine() == ELF::EM_386 &&
           Type == ELF::R_386_GOTOFF)
         return true;
-
-      // ld.lld handles R_MIPS_HI16/R_MIPS_LO16 separately, not as a whole, so
-      // it doesn't know that an R_MIPS_HI16 with implicit addend 1 and an
-      // R_MIPS_LO16 with implicit addend -32768 represents 32768, which is in
-      // range of a MergeInputSection. We could introduce a new RelExpr member
-      // (like R_RISCV_PC_INDIRECT for R_RISCV_PCREL_HI20 / R_RISCV_PCREL_LO12)
-      // but the complexity is unnecessary given that GNU as keeps the original
-      // symbol for this case as well.
-      if (TargetObjectWriter->getEMachine() == ELF::EM_MIPS &&
-          !hasRelocationAddend())
-        return true;
     }
 
     // Most TLS relocations use a got, so they need the symbol. Even those that

diff  --git a/llvm/test/MC/Mips/mips_lo16.s b/llvm/test/MC/Mips/mips_lo16.s
deleted file mode 100644
index a400f9206116..000000000000
--- a/llvm/test/MC/Mips/mips_lo16.s
+++ /dev/null
@@ -1,22 +0,0 @@
-# PR49821: Check that R_MIPS_LO16 relocs do not wrap around with large addends.
-
-# RUN: llvm-mc %s -triple mips-unknown-unknown -filetype=obj | \
-# RUN:	 llvm-objdump -d -r --no-show-raw-insn - | \
-# RUN:   FileCheck -check-prefix=MIPS32 %s
-
-# RUN: llvm-mc %s -triple mips64-unknown-unknown -filetype=obj | \
-# RUN:	 llvm-objdump -d -r --no-show-raw-insn - | \
-# RUN:   FileCheck -check-prefix=MIPS64 %s
-
-	.text
-foo:
-	lui	$2, %hi(bar)
-# MIPS32: 00000000:  R_MIPS_HI16  bar
-# MIPS64: 0000000000000000:  R_MIPS_HI16/R_MIPS_NONE/R_MIPS_NONE	.rodata.str1.1+0x8000
-	addiu	$2, $2, %lo(bar)
-# MIPS32: 00000004:  R_MIPS_LO16  bar
-# MIPS64: 0000000000000004:  R_MIPS_LO16/R_MIPS_NONE/R_MIPS_NONE	.rodata.str1.1+0x8000
-	.section	.rodata.str1.1,"aMS", at progbits,1
-	.zero 0x8000
-bar:
-	.asciz	"hello"