[clang] 24c68ea - Reland "[X86][MS-InlineAsm] Use exact conditions to recognize MS global variables"

[Phoebe Wang via cfe-commits]

Author: Phoebe Wang
Date: 2021-12-24T17:42:51+08:00
New Revision: 24c68ea1eb4fc0d0e782424ddb02da9e8c53ddf5

URL: https://github.com/llvm/llvm-project/commit/24c68ea1eb4fc0d0e782424ddb02da9e8c53ddf5
DIFF: https://github.com/llvm/llvm-project/commit/24c68ea1eb4fc0d0e782424ddb02da9e8c53ddf5.diff

LOG: Reland "[X86][MS-InlineAsm] Use exact conditions to recognize MS global variables"

This reverts commit a954558e878ed9e97e99036229e99af8c6b6c881.

Thanks Yuanfang's help. I think I found the root cause of the buildbot
fail.

The failed test has both Memory and Immediate X86Operand. All data of
different operand kinds share the same memory space by a union
definition. So it has chance we get the wrong result if we don't check
the operand kind.

It's probably it happen to be the correct value in my local environment
so that I can't reproduce the fail.

Differential Revision: https://reviews.llvm.org/D116090

Added: 
    

Modified: 
    clang/test/CodeGen/ms-inline-asm-functions.c
    llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
    llvm/lib/Target/X86/AsmParser/X86Operand.h

Removed: 
    


################################################################################
diff  --git a/clang/test/CodeGen/ms-inline-asm-functions.c b/clang/test/CodeGen/ms-inline-asm-functions.c
index c958d88038716..1a6ead9286dff 100644
--- a/clang/test/CodeGen/ms-inline-asm-functions.c
+++ b/clang/test/CodeGen/ms-inline-asm-functions.c
@@ -39,7 +39,7 @@ int bar() {
 int baz() {
   // CHECK-LABEL: _baz:
   __asm mov eax, k;
-  // CHECK: movl    k, %eax
+  // CHECK: movl    _k, %eax
   __asm mov eax, kptr;
   // CHECK: movl    _kptr, %eax
 }

diff  --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 6bae55695f3d8..2ba0b97229cc6 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -1759,7 +1759,8 @@ bool X86AsmParser::CreateMemForMSInlineAsm(
   // registers in a mmory expression, and though unaccessible via rip/eip.
   if (IsGlobalLV && (BaseReg || IndexReg)) {
     Operands.push_back(X86Operand::CreateMem(getPointerWidth(), Disp, Start,
-                                             End, Size, Identifier, Decl));
+                                             End, Size, Identifier, Decl,
+                                             FrontendSize));
     return false;
   }
   // Otherwise, we set the base register to a non-zero value

diff  --git a/llvm/lib/Target/X86/AsmParser/X86Operand.h b/llvm/lib/Target/X86/AsmParser/X86Operand.h
index 6d20c6af5fd2c..67b1244708a8c 100644
--- a/llvm/lib/Target/X86/AsmParser/X86Operand.h
+++ b/llvm/lib/Target/X86/AsmParser/X86Operand.h
@@ -286,10 +286,9 @@ struct X86Operand final : public MCParsedAsmOperand {
   bool isOffsetOfLocal() const override { return isImm() && Imm.LocalRef; }
 
   bool isMemPlaceholder(const MCInstrDesc &Desc) const override {
-    // Add more restrictions to avoid the use of global symbols. This helps
-    // with reducing the code size.
-    return !Desc.isRematerializable() && !Desc.isCall() && isMem() &&
-           !Mem.BaseReg && !Mem.IndexReg;
+    // Only MS InlineAsm uses global variables with registers rather than
+    // rip/eip.
+    return isMem() && !Mem.DefaultBaseReg && Mem.FrontendSize;
   }
 
   bool needAddressOf() const override { return AddressOf; }