[win][arm64ec] More fixes for building and testing Arm64EC Windows

[dpaoliello]

• tools/llvm-objcopy/MachO/update-section-object.test was failing on Windows since the input file (macho_sections.s) might be checked out with the wrong line ending, resulting in difference in the size of sections being checked.
• Removed the check for Windows in AArch64Arm64ECCallLowering: when llc is run without an explicit target, the module's target triple is unknown so this assert fires.
• Expect llvm/test/CodeGen/Generic/allow-check.ll to fail for Arm64EC: Global ISel is not supported.

[llvmbot]

@llvm/pr-subscribers-llvm-ir

@llvm/pr-subscribers-backend-aarch64

Author: Daniel Paoliello (dpaoliello)

Changes

• tools/llvm-objcopy/MachO/update-section-object.test was failing on Windows since the input file (macho_sections.s) might be checked out with the wrong line ending, resulting in difference in the size of sections being checked.
• The Arm64EC mangler would crash if an empty name was passed in. Trying to mangle to # resulted in downstream errors (LLVM permits empty names, but not referring to an empty name?), so added an explicit error.
• Removed the check for Windows in AArch64Arm64ECCallLowering: when llc is run without an explicit target, the module's target triple is unknown so this assert fires.
• In AArch64Arm64ECCallLowering, don't set COMDATs for functions that are declarations for the linker. These are not permitted to have COMDATs.
• Expect llvm/test/CodeGen/Generic/allow-check.ll to fail for Arm64EC: Global ISel is not supported.
• Don't use an empty function name in llvm/test/CodeGen/Generic/vector-constantexpr.ll, that's not what we're testing and it's not supported on Arm64EC.

---

Full diff: https://github.com/llvm/llvm-project/pull/151409.diff

5 Files Affected:

• (modified) llvm/.gitattributes (+1)
• (modified) llvm/lib/IR/Mangler.cpp (+3)
• (modified) llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp (+1-4)
• (modified) llvm/test/CodeGen/Generic/allow-check.ll (+1)
• (modified) llvm/test/CodeGen/Generic/vector-constantexpr.ll (+1-1)

diff --git a/llvm/.gitattributes b/llvm/.gitattributes
index fc3afb28a8d52..9f4ed8a24ecd0 100644
--- a/llvm/.gitattributes
+++ b/llvm/.gitattributes
@@ -32,3 +32,4 @@ test/tools/split-file/basic.test text eol=lf
 test/tools/split-file/Inputs/basic-*.txt eol=lf
 test/tools/split-file/basic.crlf.test text eol=crlf
 test/tools/split-file/Inputs/basic-*.crlf eol=crlf
+test/tools/llvm-objcopy/MachO/Inputs/macho_sections.s text eol=lf
diff --git a/llvm/lib/IR/Mangler.cpp b/llvm/lib/IR/Mangler.cpp
index 010bd15e256dc..894cd2dab599a 100644
--- a/llvm/lib/IR/Mangler.cpp
+++ b/llvm/lib/IR/Mangler.cpp
@@ -292,6 +292,9 @@ void llvm::emitLinkerFlagsForUsedCOFF(raw_ostream &OS, const GlobalValue *GV,
 }
 
 std::optional<std::string> llvm::getArm64ECMangledFunctionName(StringRef Name) {
+  if (Name.empty())
+    reportFatalUsageError("ARM64EC does not support empty function names");
+
   if (Name[0] != '?') {
     // For non-C++ symbols, prefix the name with "#" unless it's already
     // mangled.
diff --git a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
index 509cbb092705d..5b5c8aa1d6503 100644
--- a/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64Arm64ECCallLowering.cpp
@@ -727,9 +727,6 @@ AArch64Arm64ECCallLowering::buildPatchableThunk(GlobalAlias *UnmangledAlias,
 
 // Lower an indirect call with inline code.
 void AArch64Arm64ECCallLowering::lowerCall(CallBase *CB) {
-  assert(CB->getModule()->getTargetTriple().isOSWindows() &&
-         "Only applicable for Windows targets");
-
   IRBuilder<> B(CB);
   Value *CalledOperand = CB->getCalledOperand();
 
@@ -872,7 +869,7 @@ bool AArch64Arm64ECCallLowering::runOnModule(Module &Mod) {
     if (!F.isDeclaration() && (!F.hasLocalLinkage() || F.hasAddressTaken()) &&
         F.getCallingConv() != CallingConv::ARM64EC_Thunk_Native &&
         F.getCallingConv() != CallingConv::ARM64EC_Thunk_X64) {
-      if (!F.hasComdat())
+      if (!F.hasComdat() && !F.isDeclarationForLinker())
         F.setComdat(Mod.getOrInsertComdat(F.getName()));
       ThunkMapping.push_back(
           {&F, buildEntryThunk(&F), Arm64ECThunkType::Entry});
diff --git a/llvm/test/CodeGen/Generic/allow-check.ll b/llvm/test/CodeGen/Generic/allow-check.ll
index 148ee811ea806..97719a7af6229 100644
--- a/llvm/test/CodeGen/Generic/allow-check.ll
+++ b/llvm/test/CodeGen/Generic/allow-check.ll
@@ -6,6 +6,7 @@
 ; XFAIL: target=nvptx{{.*}}
 ; XFAIL: target=sparc{{.*}}
 ; XFAIL: target=hexagon-{{.*}}
+; XFAIL: target=arm64ec-{{.*}}
 
 ; RUN: llc < %s -O3 -global-isel=0 -fast-isel=0
 ; RUN: llc < %s -O3 -global-isel=1 -fast-isel=0
diff --git a/llvm/test/CodeGen/Generic/vector-constantexpr.ll b/llvm/test/CodeGen/Generic/vector-constantexpr.ll
index 416367fa3b52a..6e6a0c18d92d5 100644
--- a/llvm/test/CodeGen/Generic/vector-constantexpr.ll
+++ b/llvm/test/CodeGen/Generic/vector-constantexpr.ll
@@ -1,6 +1,6 @@
 ; RUN: llc < %s
 	
-define void @""(ptr %inregs, ptr %outregs) {
+define void @test(ptr %inregs, ptr %outregs) {
         %a_addr.i = alloca <4 x float>          ; <ptr> [#uses=1]
         store <4 x float> < float undef, float undef, float undef, float undef >, ptr %a_addr.i
         ret void

[efriedma-quic]

LLVM supports unnamed global variables and function; if such a function actually needs a name, we invent one later. (See Mangler::getNameWithPrefix.) Not really that useful, or frequently used, but it's there. I guess we can make AArch64Arm64ECCallLowering introduce names if they're necessary. If you're not going to fix it, please open a bug.

Please split out the available_externally fix, with an appropriate testcase.

[dpaoliello]

LLVM supports unnamed global variables and function; if such a function actually needs a name, we invent one later. (See Mangler::getNameWithPrefix.) Not really that useful, or frequently used, but it's there. I guess we can make AArch64Arm64ECCallLowering introduce names if they're necessary. If you're not going to fix it, please open a bug.

Please split out the available_externally fix, with an appropriate testcase.

Both of these have been fixed in other PRs, so this PR is ready to land now.