[PowerPC][clang] Fix triple constructor ambiguity causing "unknown" target triple on AIX

[tonykuttai]

PR #145685 introduced constructor overload ambiguity in the Triple class, causing updateTripleOSVersion() to construct Triple objects with unknown instead of the configured target triple (e.g., powerpc-ibm-aix7.3.0.0). This results in Clang driver errors like error: unknown target triple 'unknown'.

Used Twine constructor with braced initialization to bypass ambiguity.

[arsenm]

Is this testable? The TargetParser really shouldn't depend on the host triple for any reason

[arsenm]

This function shouldn't depend on the host triple in the first place

[tonykuttai]

Added a test file to lock this down.

[hubert-reinterpretcast]

This function shouldn't depend on the host triple in the first place

This function intends to transfer host characteristics (the OS version information) to AIX target triples (which is then used in Clang for predefined macros, among other things). The host characteristics have no reasonable relation to the AIX target triple unless the compiler is hosted on AIX.

[llvmbot]

@llvm/pr-subscribers-clang

Author: Tony Varghese (tonykuttai)

Changes

PR #145685 introduced constructor overload ambiguity in the Triple class, causing updateTripleOSVersion() to construct Triple objects with unknown instead of the configured target triple (e.g., powerpc-ibm-aix7.3.0.0). This results in Clang driver errors like error: unknown target triple 'unknown'.

Used Twine constructor with braced initialization to bypass ambiguity.

---

Full diff: https://github.com/llvm/llvm-project/pull/147488.diff

2 Files Affected:

• (added) clang/test/Driver/aix-default-target-triple.c (+18)
• (modified) llvm/lib/TargetParser/Unix/Host.inc (+1-1)

diff --git a/clang/test/Driver/aix-default-target-triple.c b/clang/test/Driver/aix-default-target-triple.c
new file mode 100644
index 0000000000000..2802e6a60719a
--- /dev/null
+++ b/clang/test/Driver/aix-default-target-triple.c
@@ -0,0 +1,18 @@
+// Test for the Triple constructor ambiguity fix on AIX
+// This test verifies that the default target triple is correctly resolved
+// and doesn't fall back to "unknown" due to constructor ambiguity.
+
+// REQUIRES: system-aix
+// RUN: %clang -v %s -c 2>&1 | FileCheck %s --check-prefix=CHECK-TARGET
+
+// Test that the target triple contains AIX and is not "unknown"
+// The target should be something like "powerpc-ibm-aix7.3.0.0"
+// CHECK-TARGET: Target: {{.*}}aix{{.*}}
+// CHECK-TARGET-NOT: error: unknown target triple 'unknown'
+
+#include <stdio.h>
+
+int main() {
+    printf("Target triple resolution test passed\n");
+    return 0;
+}
diff --git a/llvm/lib/TargetParser/Unix/Host.inc b/llvm/lib/TargetParser/Unix/Host.inc
index ef9e288ee3a01..aeb2f59218700 100644
--- a/llvm/lib/TargetParser/Unix/Host.inc
+++ b/llvm/lib/TargetParser/Unix/Host.inc
@@ -55,7 +55,7 @@ static std::string updateTripleOSVersion(std::string TargetTripleString) {
   // On AIX, the AIX version and release should be that of the current host
   // unless if the version has already been specified.
   if (Triple(LLVM_HOST_TRIPLE).getOS() == Triple::AIX) {
-    Triple TT(std::move(TargetTripleString));
+    Triple TT{TargetTripleString};
     if (TT.getOS() == Triple::AIX && !TT.getOSMajorVersion()) {
       struct utsname name;
       if (uname(&name) != -1) {

[llvmbot]

@llvm/pr-subscribers-clang-driver

Author: Tony Varghese (tonykuttai)

Changes

PR #145685 introduced constructor overload ambiguity in the Triple class, causing updateTripleOSVersion() to construct Triple objects with unknown instead of the configured target triple (e.g., powerpc-ibm-aix7.3.0.0). This results in Clang driver errors like error: unknown target triple 'unknown'.

Used Twine constructor with braced initialization to bypass ambiguity.

---

Full diff: https://github.com/llvm/llvm-project/pull/147488.diff

2 Files Affected:

• (added) clang/test/Driver/aix-default-target-triple.c (+18)
• (modified) llvm/lib/TargetParser/Unix/Host.inc (+1-1)

diff --git a/clang/test/Driver/aix-default-target-triple.c b/clang/test/Driver/aix-default-target-triple.c
new file mode 100644
index 0000000000000..2802e6a60719a
--- /dev/null
+++ b/clang/test/Driver/aix-default-target-triple.c
@@ -0,0 +1,18 @@
+// Test for the Triple constructor ambiguity fix on AIX
+// This test verifies that the default target triple is correctly resolved
+// and doesn't fall back to "unknown" due to constructor ambiguity.
+
+// REQUIRES: system-aix
+// RUN: %clang -v %s -c 2>&1 | FileCheck %s --check-prefix=CHECK-TARGET
+
+// Test that the target triple contains AIX and is not "unknown"
+// The target should be something like "powerpc-ibm-aix7.3.0.0"
+// CHECK-TARGET: Target: {{.*}}aix{{.*}}
+// CHECK-TARGET-NOT: error: unknown target triple 'unknown'
+
+#include <stdio.h>
+
+int main() {
+    printf("Target triple resolution test passed\n");
+    return 0;
+}
diff --git a/llvm/lib/TargetParser/Unix/Host.inc b/llvm/lib/TargetParser/Unix/Host.inc
index ef9e288ee3a01..aeb2f59218700 100644
--- a/llvm/lib/TargetParser/Unix/Host.inc
+++ b/llvm/lib/TargetParser/Unix/Host.inc
@@ -55,7 +55,7 @@ static std::string updateTripleOSVersion(std::string TargetTripleString) {
   // On AIX, the AIX version and release should be that of the current host
   // unless if the version has already been specified.
   if (Triple(LLVM_HOST_TRIPLE).getOS() == Triple::AIX) {
-    Triple TT(std::move(TargetTripleString));
+    Triple TT{TargetTripleString};
     if (TT.getOS() == Triple::AIX && !TT.getOSMajorVersion()) {
       struct utsname name;
       if (uname(&name) != -1) {

[arsenm]

lgtm with test nits

[hubert-reinterpretcast]

@tonykuttai, this is not sufficient. The target also has to be AIX to begin with (as opposed to an AIX-hosted cross-compiling configuration).