[llvm-branch-commits] [llvm] a981a4f - [X86] Always use 64-bit relocations in no-PIC large code model (#89101)

[Tom Stellard via llvm-branch-commits]

Author: Arthur Eubanks
Date: 2024-04-23T08:59:40-07:00
New Revision: a981a4f7653c112277817da3b661e9e6b24389ac

URL: https://github.com/llvm/llvm-project/commit/a981a4f7653c112277817da3b661e9e6b24389ac
DIFF: https://github.com/llvm/llvm-project/commit/a981a4f7653c112277817da3b661e9e6b24389ac.diff

LOG: [X86] Always use 64-bit relocations in no-PIC large code model (#89101)

This matches other types of relocations, e.g. to constant pool. And
makes things more consistent with PIC large code model.

Some users of the large code model may not place small data in the lower
2GB of the address space (e.g.
https://github.com/ClangBuiltLinux/linux/issues/2016), so just
unconditionally use 64-bit relocations in the large code model.

So now functions in a section not marked large will use 64-bit
relocations to reference everything when using the large code model.

This also fixes some lldb tests broken by #88172
(https://lab.llvm.org/buildbot/#/builders/68/builds/72458).

(cherry picked from commit 6cea7c491f4c4c68aa0494a9b18f36ff40c22c81)

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
    llvm/test/CodeGen/X86/code-model-elf.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 833f058253d880..553d338b77904a 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2923,11 +2923,10 @@ bool X86DAGToDAGISel::selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
 }
 
 bool X86DAGToDAGISel::selectMOV64Imm32(SDValue N, SDValue &Imm) {
-  // Cannot use 32 bit constants to reference objects in kernel code model.
-  // Cannot use 32 bit constants to reference objects in large PIC mode since
-  // GOTOFF is 64 bits.
+  // Cannot use 32 bit constants to reference objects in kernel/large code
+  // model.
   if (TM.getCodeModel() == CodeModel::Kernel ||
-      (TM.getCodeModel() == CodeModel::Large && TM.isPositionIndependent()))
+      TM.getCodeModel() == CodeModel::Large)
     return false;
 
   // In static codegen with small code model, we can get the address of a label

diff  --git a/llvm/test/CodeGen/X86/code-model-elf.ll b/llvm/test/CodeGen/X86/code-model-elf.ll
index afcffb3a7adeda..b6634403dc1d05 100644
--- a/llvm/test/CodeGen/X86/code-model-elf.ll
+++ b/llvm/test/CodeGen/X86/code-model-elf.ll
@@ -346,7 +346,7 @@ define dso_local ptr @lea_forced_small_data() #0 {
 ;
 ; LARGE-STATIC-LABEL: lea_forced_small_data:
 ; LARGE-STATIC:       # %bb.0:
-; LARGE-STATIC-NEXT:    movl $forced_small_data, %eax
+; LARGE-STATIC-NEXT:    movabsq $forced_small_data, %rax
 ; LARGE-STATIC-NEXT:    retq
 ;
 ; SMALL-PIC-LABEL: lea_forced_small_data:
@@ -399,7 +399,7 @@ define dso_local i32 @load_forced_small_data() #0 {
 ;
 ; LARGE-STATIC-LABEL: load_forced_small_data:
 ; LARGE-STATIC:       # %bb.0:
-; LARGE-STATIC-NEXT:    movl $forced_small_data+8, %eax
+; LARGE-STATIC-NEXT:    movabsq $forced_small_data+8, %rax
 ; LARGE-STATIC-NEXT:    movl (%rax), %eax
 ; LARGE-STATIC-NEXT:    retq
 ;