[openmp][wasm] Fix microtask type mismatch (#84355)

When OpenMP is compiled for WebAssembly (see #71297), it invokes a
microtask via a `switch` statement that dispatches to the `void *`
microtask pointer with spelled-out arguments (not varargs). As #83329
points out, however, this can result in a type mismatch when the
indirect call is executed by WebAssembly; WebAssembly expects the called
pointer to have the precise type of the call site. This change fixes the
issue by bringing back the approach in [D142593] of type-casting all the
`switch` arms to the precise type. This fixes #83329.

[D142593]: https://reviews.llvm.org/D142593

1 files changed, 77 insertions, 30 deletions

diff --git a/openmp/runtime/src/z_Linux_util.cpp b/openmp/runtime/src/z_Linux_util.cpp
index 3f831d6..d751a41 100644
--- a/openmp/runtime/src/z_Linux_util.cpp
+++ b/openmp/runtime/src/z_Linux_util.cpp
@@ -2610,6 +2610,43 @@ finish: // Clean up and exit.
       KMP_ARCH_PPC64 || KMP_ARCH_RISCV64 || KMP_ARCH_LOONGARCH64 ||            \
       KMP_ARCH_ARM || KMP_ARCH_VE || KMP_ARCH_S390X || KMP_ARCH_PPC_XCOFF)
 
+// Because WebAssembly will use `call_indirect` to invoke the microtask and
+// WebAssembly indirect calls check that the called signature is a precise
+// match, we need to cast each microtask function pointer back from `void *` to
+// its original type.
+typedef void (*microtask_t0)(int *, int *);
+typedef void (*microtask_t1)(int *, int *, void *);
+typedef void (*microtask_t2)(int *, int *, void *, void *);
+typedef void (*microtask_t3)(int *, int *, void *, void *, void *);
+typedef void (*microtask_t4)(int *, int *, void *, void *, void *, void *);
+typedef void (*microtask_t5)(int *, int *, void *, void *, void *, void *,
+                             void *);
+typedef void (*microtask_t6)(int *, int *, void *, void *, void *, void *,
+                             void *, void *);
+typedef void (*microtask_t7)(int *, int *, void *, void *, void *, void *,
+                             void *, void *, void *);
+typedef void (*microtask_t8)(int *, int *, void *, void *, void *, void *,
+                             void *, void *, void *, void *);
+typedef void (*microtask_t9)(int *, int *, void *, void *, void *, void *,
+                             void *, void *, void *, void *, void *);
+typedef void (*microtask_t10)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *);
+typedef void (*microtask_t11)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *,
+                              void *);
+typedef void (*microtask_t12)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *,
+                              void *, void *);
+typedef void (*microtask_t13)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *,
+                              void *, void *, void *);
+typedef void (*microtask_t14)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *,
+                              void *, void *, void *, void *);
+typedef void (*microtask_t15)(int *, int *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *, void *,
+                              void *, void *, void *, void *, void *);
+
 // we really only need the case with 1 argument, because CLANG always build
 // a struct of pointers to shared variables referenced in the outlined function
 int __kmp_invoke_microtask(microtask_t pkfn, int gtid, int tid, int argc,
@@ -2629,66 +2666,76 @@ int __kmp_invoke_microtask(microtask_t pkfn, int gtid, int tid, int argc,
     fflush(stderr);
     exit(-1);
   case 0:
-    (*pkfn)(&gtid, &tid);
+    (*(microtask_t0)pkfn)(&gtid, &tid);
     break;
   case 1:
-    (*pkfn)(&gtid, &tid, p_argv[0]);
+    (*(microtask_t1)pkfn)(&gtid, &tid, p_argv[0]);
     break;
   case 2:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1]);
+    (*(microtask_t2)pkfn)(&gtid, &tid, p_argv[0], p_argv[1]);
     break;
   case 3:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2]);
+    (*(microtask_t3)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2]);
     break;
   case 4:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3]);
+    (*(microtask_t4)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3]);
     break;
   case 5:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4]);
+    (*(microtask_t5)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3], p_argv[4]);
     break;
   case 6:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5]);
+    (*(microtask_t6)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3], p_argv[4], p_argv[5]);
     break;
   case 7:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6]);
+    (*(microtask_t7)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3], p_argv[4], p_argv[5], p_argv[6]);
     break;
   case 8:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7]);
+    (*(microtask_t8)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                          p_argv[7]);
     break;
   case 9:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8]);
+    (*(microtask_t9)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                          p_argv[3], p_argv[4], p_argv[5], p_argv[6], p_argv[7],
+                          p_argv[8]);
     break;
   case 10:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9]);
+    (*(microtask_t10)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9]);
     break;
   case 11:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10]);
+    (*(microtask_t11)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9], p_argv[10]);
     break;
   case 12:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
-            p_argv[11]);
+    (*(microtask_t12)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+                           p_argv[11]);
     break;
   case 13:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
-            p_argv[11], p_argv[12]);
+    (*(microtask_t13)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+                           p_argv[11], p_argv[12]);
     break;
   case 14:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
-            p_argv[11], p_argv[12], p_argv[13]);
+    (*(microtask_t14)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+                           p_argv[11], p_argv[12], p_argv[13]);
     break;
   case 15:
-    (*pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2], p_argv[3], p_argv[4],
-            p_argv[5], p_argv[6], p_argv[7], p_argv[8], p_argv[9], p_argv[10],
-            p_argv[11], p_argv[12], p_argv[13], p_argv[14]);
+    (*(microtask_t15)pkfn)(&gtid, &tid, p_argv[0], p_argv[1], p_argv[2],
+                           p_argv[3], p_argv[4], p_argv[5], p_argv[6],
+                           p_argv[7], p_argv[8], p_argv[9], p_argv[10],
+                           p_argv[11], p_argv[12], p_argv[13], p_argv[14]);
     break;
   }