[PATCH] D119278: [LLD] Fix issue in HIP toolchain due to unspecified order of evaluation of the function object

[Alexandre Ganea via Phabricator via llvm-commits]

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This fixes the issue raised in https://reviews.llvm.org/D108850#3303452

Before C++17, the function object is evaluated in a unspecified order. In the following example: https://godbolt.org/z/8ao4vdsr7 the function object is either evaluated before or after the arguments, depending on the compiler. With MSVC and /std:c++14 the function object is evaluated after the arguments; with clang and gcc, it is evaluated before. With C++17, the function object is guaranteed to be evaluated before the arguments, see: https://riptutorial.com/cplusplus/example/19369/evaluation-order-of-function-arguments

In our case, the issue was that the `args` conversion to `ArrayRef` as evaluated before the lambda call `link`, which internally was calling `parseFlavor()`, which in turned modified `args`. We ended with an `ArrayRef` argument that reflected the previous value of `args`.

Add coverage for `-flavor` which we didn't have before.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D119278

Files:
  lld/test/ELF/amdgpu-duplicate-sym.s
  lld/tools/lld/lld.cpp


Index: lld/tools/lld/lld.cpp
===================================================================
--- lld/tools/lld/lld.cpp
+++ lld/tools/lld/lld.cpp
@@ -159,9 +159,9 @@
       die("lld is a generic driver.\n"
           "Invoke ld.lld (Unix), ld64.lld (macOS), lld-link (Windows), wasm-ld"
           " (WebAssembly) instead");
-  };
+  }();
   // Run the driver. If an error occurs, false will be returned.
-  bool r = link()(args, stdoutOS, stderrOS, exitEarly, inTestOutputDisabled);
+  bool r = link(args, stdoutOS, stderrOS, exitEarly, inTestOutputDisabled);
 
   // Call exit() if we can to avoid calling destructors.
   if (exitEarly)
Index: lld/test/ELF/amdgpu-duplicate-sym.s
===================================================================
--- /dev/null
+++ lld/test/ELF/amdgpu-duplicate-sym.s
@@ -0,0 +1,32 @@
+# REQUIRES: amdgpu
+# RUN: llvm-mc -filetype=obj -triple amdgcn-amd-amdhsa -mcpu=gfx1031 --position-independent --relax-relocations %s -o %t.o
+
+# We use lld-link on purpose to excercice -flavor.
+# RUN: lld-link -flavor gnu -shared %t.o
+
+        .text
+        .amdgcn_target "amdgcn-amd-amdhsa--gfx1031"
+        .p2alignl 6, 3214868480
+        .fill 48, 4, 3214868480
+        .protected      xxx                     ; @xxx
+        .type   xxx, at object
+        .data
+        .globl  xxx
+        .p2align        2
+xxx:
+        .long   123                             ; 0x7b
+        .size   xxx, 4
+
+        .ident  "clang version 14.0.0 (git at github.amd.com:Compute-Mirrors/llvm-project.git ce53ba9aaee8d053604883d5befaf07bad60ba84)"
+        .section        ".note.GNU-stack"
+        .addrsig
+        .amdgpu_metadata
+---
+amdhsa.kernels:  []
+amdhsa.target:   amdgcn-amd-amdhsa--gfx1031
+amdhsa.version:
+  - 1
+  - 1
+...
+
+        .end_amdgpu_metadata


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