[WebAssembly] Add -i128:128 to the datalayout string.

Clang [defaults to aligning `__int128_t` to 16 bytes], while LLVM `datalayout` strings [default to aligning `i128` to 8 bytes]. Wasm is currently using the defaults for both, so it's inconsistent. Fix this by adding `-i128:128` to Wasm's `datalayout` string so that it aligns `i28` to 16 bytes too. This is similar to dbad963 for SPARC. This fixes rust-lang/rust#133991; see that issue for further discussion. [defaults to aligning `__int128_t` to 16 bytes]: https://github.com/llvm/llvm-project/blob/f8b4182f076f8fe55f9d5f617b5a25008a77b22f/clang/lib/Basic/TargetInfo.cpp#L77 [default to aligning `i128` to 8 bytes]: https://llvm.org/docs/LangRef.html#langref-datalayout
sunfishcode · Dec 9, 2024 · 337b104 · 337b104
1 parent 00b07aa
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Showing 6 changed files with 55 additions and 15 deletions.
diff --git a/clang/lib/Basic/Targets/WebAssembly.h b/clang/lib/Basic/Targets/WebAssembly.h
@@ -183,11 +183,12 @@ class LLVM_LIBRARY_VISIBILITY WebAssembly32TargetInfo
                                    const TargetOptions &Opts)
       : WebAssemblyTargetInfo(T, Opts) {
     if (T.isOSEmscripten())
-      resetDataLayout("e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-f128:64-n32:64-"
-                      "S128-ni:1:10:20");
-    else
       resetDataLayout(
-          "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20");
+          "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-f128:64-n32:64-"
+          "S128-ni:1:10:20");
+    else
+      resetDataLayout("e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-"
+                      "S128-ni:1:10:20");
   }
 
 protected:
@@ -207,11 +208,12 @@ class LLVM_LIBRARY_VISIBILITY WebAssembly64TargetInfo
     PtrDiffType = SignedLong;
     IntPtrType = SignedLong;
     if (T.isOSEmscripten())
-      resetDataLayout("e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-f128:64-n32:64-"
-                      "S128-ni:1:10:20");
-    else
       resetDataLayout(
-          "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20");
+          "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-i128:128-f128:64-n32:64-"
+          "S128-ni:1:10:20");
+    else
+      resetDataLayout("e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-"
+                      "S128-ni:1:10:20");
   }
 
 protected:

diff --git a/clang/test/CodeGen/target-data.c b/clang/test/CodeGen/target-data.c
@@ -108,11 +108,11 @@
 
 // RUN: %clang_cc1 -triple wasm32-unknown-unknown -o - -emit-llvm %s | \
 // RUN: FileCheck %s -check-prefix=WEBASSEMBLY32
-// WEBASSEMBLY32: target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
+// WEBASSEMBLY32: target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20"
 
 // RUN: %clang_cc1 -triple wasm64-unknown-unknown -o - -emit-llvm %s | \
 // RUN: FileCheck %s -check-prefix=WEBASSEMBLY64
-// WEBASSEMBLY64: target datalayout = "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
+// WEBASSEMBLY64: target datalayout = "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20"
 
 // RUN: %clang_cc1 -triple lanai-unknown-unknown -o - -emit-llvm %s | \
 // RUN: FileCheck %s -check-prefix=LANAI

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
@@ -5559,7 +5559,7 @@ std::string llvm::UpgradeDataLayoutString(StringRef DL, StringRef TT) {
     return Res;
   }
 
-  if (T.isSPARC() || (T.isMIPS64() && !DL.contains("m:m"))) {
+  if (T.isSPARC() || (T.isMIPS64() && !DL.contains("m:m")) || T.isWasm()) {
     // Mips64 with o32 ABI did not add "-i128:128".
     // Add "-i128:128"
     std::string I64 = "-i64:64";

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -118,13 +118,13 @@ WebAssemblyTargetMachine::WebAssemblyTargetMachine(
           T,
           TT.isArch64Bit()
               ? (TT.isOSEmscripten() ? "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-"
-                                       "f128:64-n32:64-S128-ni:1:10:20"
+                                       "i128:128-f128:64-n32:64-S128-ni:1:10:20"
                                      : "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-"
-                                       "n32:64-S128-ni:1:10:20")
+                                       "i128:128-n32:64-S128-ni:1:10:20")
               : (TT.isOSEmscripten() ? "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-"
-                                       "f128:64-n32:64-S128-ni:1:10:20"
+                                       "i128:128-f128:64-n32:64-S128-ni:1:10:20"
                                      : "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-"
-                                       "n32:64-S128-ni:1:10:20"),
+                                       "i128:128-n32:64-S128-ni:1:10:20"),
           TT, CPU, FS, Options, getEffectiveRelocModel(RM, TT),
           getEffectiveCodeModel(CM, CodeModel::Large), OL),
       TLOF(new WebAssemblyTargetObjectFile()),

diff --git a/llvm/test/CodeGen/WebAssembly/data-align.ll b/llvm/test/CodeGen/WebAssembly/data-align.ll
@@ -0,0 +1,26 @@
+; RUN: llc < %s -march=wasm32 | FileCheck %s
+; RUN: llc < %s -march=wasm64 | FileCheck %s
+
+; CHECK:      .Li8:
+; CHECK-DAG: .size .Li8, 1
+@i8 = private constant i8 42
+
+; CHECK:      .p2align 1
+; CHECK-NEXT: .Li16:
+; CHECK-DAG:  .size .Li16, 2
+@i16 = private constant i16 42
+
+; CHECK:      .p2align 2
+; CHECK-NEXT: .Li32:
+; CHECK-DAG:  .size .Li32, 4
+@i32 = private constant i32 42
+
+; CHECK:      .p2align 3
+; CHECK-NEXT: .Li64:
+; CHECK-DAG:  .size .Li64, 8
+@i64 = private constant i64 42
+
+; CHECK:      .p2align 4
+; CHECK-NEXT: .Li128:
+; CHECK-DAG:  .size .Li128, 16
+@i128 = private constant i128 42
diff --git a/llvm/unittests/Bitcode/DataLayoutUpgradeTest.cpp b/llvm/unittests/Bitcode/DataLayoutUpgradeTest.cpp
@@ -92,6 +92,18 @@ TEST(DataLayoutUpgradeTest, ValidDataLayoutUpgrade) {
                 "e-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64", "mips64el"),
             "e-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64");
 
+  // Check that WebAssembly targets add -i128:128.
+  EXPECT_EQ(
+      UpgradeDataLayoutString(
+          "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20",
+          "wasm32"),
+      "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20");
+  EXPECT_EQ(
+      UpgradeDataLayoutString(
+          "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20",
+          "wasm64"),
+      "e-m:e-p:64:64-p10:8:8-p20:8:8-i64:64-i128:128-n32:64-S128-ni:1:10:20");
+
   // Check that SPIR && SPIRV targets add -G1 if it's not present.
   EXPECT_EQ(UpgradeDataLayoutString("e-p:32:32", "spir"), "e-p:32:32-G1");
   EXPECT_EQ(UpgradeDataLayoutString("e-p:32:32", "spir64"), "e-p:32:32-G1");